Progress 10/01/09 to 09/30/14
Outputs
Target Audience: Animal nutritionists. Feedlot cattle industry. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Dried sugar beets. Substitution of steam-flaked corn with chopped dried sugar beets did not affect ADG or carcass quality. The NE value of the dried beet was 2.15 and 1.48 Mcal/kg for maintenance and gain, respectively (comparable to wheat grain Oyster shell and limestone as alkalizing agents. Notwithstanding the greater reactivity of oyster shell vs. limestone, increasing supplemental levels of these alkalizing agents beyond that required to meet Ca requirements for maintenance and tissue growth had minimal effects on ruminal pH and digestive function. Zilpaterol effects on Holstein meat quality. Results illustrate that supplementation with the beta agonist zilpaterol in diets for calf-fed Holstein steers during the final 20 to 40 d on feed has minimal effects on purge, thaw, or cooking loss. Percentage of intramuscular fat will decrease, especially when fed for longer durations. Steaks from zilpaterol treated steers were less tender than steaks from control animals at all aging times, but treatment effects were ameliorated following postmortem aging. White corn evaluation. Characteristics of ruminal, postruminal and total tract digestion of OM, starch, and N were similar steam-flaked yellow and white corn treatments. Decreasing flake density of white corn did not affect ruminal OM digestion, but increased total tract OM digestion. Compared with dry rolling, steam flaking white corn increased ruminal, postruminal and total tract OM digestion, reflecting corresponding increases in ruminal, postruminal and total tract starch digestion. Apparent postruminal and total-tract N digestion also were greater for steam-flaked white corn than for dry rolled white corn. The DE value of steam-flaked white and yellow corn were similar. Compared with dry rolling, steam flaking markedly enhances the feeding value of white corn, optimal flake density being less than 0.36 kg/L. Although white corn has greater vitreous endosperm content, characteristics of ruminal starch digestion and UIP are similar to conventional yellow dent corn when processed to a similar flake density (0.31 kg/L). However, postruminal and total tract starch digestion tends to be slightly lower for flaked white corn than for yellow corn. Surfactant supplementation and fat digestion. There were no surfactant by supplemental fat interactions. Surfactant did not affect site and extent of OM, starch, N, ADF, and fatty acid digestion, or DE value of diet. Supplemental fat decreased ruminal and total tract digestion of OM and ADF and increased the DE value of diet. The decrease in postruminal FA digestion was mainly due to decreased digestion of C18:0. Digestible energy of supplemental fat averaged 6.87Mcal/kg. Independent of method of addition, supplementing high-fat diets with surfactant Tween 80 does enhance intestinal digestion of fat in Holstein steers fed a high-fat finishing diets. Fungal infested corn. There were no treatment effects on ruminal pH or volatile fatty acids molar proportions. Ruminal digestion of organic matter, and feed N decreased with increasing levels of fungal infested flaked corn in the diet. There were no treatment effects on net microbial N synthesis. Total tract digestion of OM, N and energy decreased with increasing fungal infested corn. Ruminal and total tract digestion of ADF and starch were not affected by treatments. It is concluded that mold infestation diminishes the feeding value of steam-flaked corn. The consequence was not related to effects of fungal growth on characteristics of digestion, but rather, to loss of readily digestible nutrients (starch) through the spoilage process, and to a lesser extent, decreased N digestibility. Dried distillers grains for calf-fed Holstein steers. Study reveals that the NEm and NEg values for DDGS in SF corn-based diets for the calf-fed Holstein are consistent with current tabular standards (2.18 and 1.50 Mcal/kg, respectively. Extra-caloric value of DDGS as a metabolizable amino acid source is apparent in light-weight calves during the initial growing phase, with maximal overall responses occurring at the 20% level of supplementation. The UIP value of DDGS used in this study (35%) was considerably less than current tabular estimates (52%; NRC, 2000). Intestinal digestion of DDGS fatty acids diminishes as a predictable function of total dietary fatty acid intake, placing upper constraints on levels of DDGS supplementation. Partial replacement of SF corn with DDGS may increase ruminal acetate:propionate ratio, and hence, estimated methane production. Optimal forage NDF for calf-fed Holstein steers. Study reveals that differences among forage sources are minimized when forages are compared at similar levels of forage NDF concentration. Compared to ground, pelleted rice straw in finishing diets may produce lower ruminal pH and growth-performance of calf-fed Holstein steers. Vitamin A and E supplementation of calf-fed Holstein steers. Vitamin E supplemented above basal requirements during long-term growing-finishing period in Holstein calves results in slight to no effect on animal performance or carcass characteristics. Form vitamin affected plasma retinol concentration with no effects on growth performance or carcass characteristics. Vitamin A supplementation increased ADG. However, this effect was due to enhanced feed intake. Supplemental vitamin A did not affect gain efficiency or dietary net energy. Growth performance responses to ester forms of vitamin A (retinyl propionate vs retinyl palmitate) were comparable. Based on plasma tocopherol levels, the basal non-supplemented growing-finishing diet was not deficient in vitamin E.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
J. Salinas-Chavira, A. A. Arrizon, A. Barreras, C. Z. Chen , A. Plascencia , and R. A. Zinn. 2014. Evaluation of supplemental vitamin A and E on 56-day growth performance, dietary net energy, and plasma retinol and tocopherol concentrations in Holstein steer calves. Prof. Anim. Sci. 30:510-514.
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: Animal nutritionists. Feedlot cattle industry. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? Evaluate vitamin A and E supplementation.
Impacts
What was accomplished under these goals?
Study reveals that differences among forage sources are minimized when forages are compared at similar levels of forage NDF concentration. Compared to ground, pelleted rice straw in finishing diets may produce lower ruminal pH and growth-performance of calf-fed Holstein steers.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Salinas-Chaveria, J., E. Alverez, M. F. Montano, and R. A. Zinn. 2013. INfluence of forage NDF level, source and pelletizing on growth performance, dietary energetics, and characteristics of digestive function for feedlot Cattle. Anim. Feed Sci. Techol. 183(3):106-115
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Two experiments were conducted to examine the effect of level of dried distillers grains plus solubles (DDGS) supplementation (0, 10, 20, and 30%, DM basis), replacing steam-flaked (SF) corn in finishing diets, on characteristics of digestion (Exp. 1) and growth performance (Exp. 2) in calf-fed Holstein steers fed. In Exp.1, four cannulated Holstein steers (349 kg) were used to evaluate treatment effects on characteristics of digestion. In Exp.2, 144 Holsteins steer (112 kg) were used in a 305-d trial to evaluate treatment effects on growth performance and carcass characteristics. PARTICIPANTS: Two students ( Angel Arrizon, Ramses Carrasco) and two collaborating scientist (Alejandro Plascencia and Noemi Torrentera) from UABC, Mexicali, Mexico (the UABC campus is located about 10 miles south of the UC, DREC research facility where this work is conducted). TARGET AUDIENCES: Research is designed to enhance knowledge, and address practical immediate concerns regarding nutrition, management and health of feedlot cattle, particularly the calf-fed Holstein. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Study reveals that the NEm and NEg values for DDGS in SF corn-based diets for the calf-fed Holstein are consistent with current tabular standards (2.18 and 1.50 Mcal/kg, respectively. Extra-caloric value of DDGS as a metabolizable amino acid source is apparent in light-weight calves during the initial growing phase, with maximal overall responses occurring at the 20% level of supplementation. The UIP value of DDGS used in this study (35%) was considerably less than current tabular estimates (52%; NRC, 2000). Intestinal digestion of DDGS fatty acids diminishes as a predictable function of total dietary fatty acid intake, placing upper constraints on levels of DDGS supplementation. Partial replacement of SF corn with DDGS may increase ruminal acetate:propionate ratio, and hence, estimated methane production.
Publications
- R. Carrasco, A. A. Arrizon, A. Plascencia, N. G. Torrentera, R. A. Zinn. 2013. Comparative feeding value of distillers dried grains plus solubles as a partial replacement for steam-flaked corn in diets for calf-fed Holstein steers: characteristics of digestion, growth-performance, and dietary energetics. J. Anim. Sci 91: in press
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Two experiments were conducted to evaluate the comparative feeding value of dried shredded sugarbeets (DSSB; 0, 20, and 40% of diet DM) as a replacement for steam-flaked corn in finishing diets for feedlot cattle. In experiment one, sixty calf-fed Holstein steers (476 plus minus 6.3 kg) were used in a 97-d finishing trial. In experiment two, six cannulated Holstein steers (205 kg) were used in a replicated 3x3 Latin square design to evaluate treatment effects on digestion. PARTICIPANTS: Two students ( Angel Arrizon, Ramses Carrasco) and three collaborating scientist (Martin Montano , Noemi Torrentera, and Jaime Salinas) from UABC, Mexicali, Mexico (the UABC campus is located about 10 miles south of the UC, DREC research facility where this work is conducted). TARGET AUDIENCES: Research is designed to enhance knowledge, and address practical immediate concerns regarding nutrition, management and health of feedlot cattle, particularly the calf-fed Holstein. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Increasing level of dried shredded sugar beet replacement for steam-flaked corn decreased gain efficiency (ADG:DMI) and dietary net energy. Given that flaked corn has a NEm value of 2.38 Mcal/kg, the replacement NEm and NEg values for dried shredded sugar beets were 1.94 and 1.29 Mcal/kg, respectively. There were no treatment effects on carcass characteristics. Ruminal digestion of starch, NDF, and feed N were not affected, although ruminal OM digestion tended to increase with increasing level of sugar beet substitution. Replacing flaked corn with dried shredded sugar beets decreased flow of starch to the small intestine, but increased flow of microbial N. There were no treatment effects on postruminal digestion of OM, NDF, starch or feed N, or total tract digestion of OM, starch and N. Substitution of dried shredded sugar beets for flaked corn increased total tract NDF digestion, and decreased dietary DE. Given that steam-flaked corn has a DE value of 4.19 Mcal/kg, the replacement DE value of dried shredded sugar beets was 3.68 Mcal/kg. There were no treatment effects on ruminal pH or total VFA; however, substitution with dried shredded sugar beets decreased propionate, increased acetate, butyrate, valerate, and estimated methane production. It was concluded that dried shredded sugar beets may replace flaked corn in finishing diets at levels of up to 40% without detrimental effects on ADG and carcass characteristics. The NE value of dried shredded sugar beets is 82% that of flaked corn (DM basis). Partial replacement of steam-flaked corn with dried shredded sugar beets alters ruminal VFA patterns, increasing estimated methane energy loss; slightly decreasing the efficiency of DE utilization.
Publications
- Arrizon, A., R. Carrasco, J. Salinas, M. Montano, N. Torrentera, R.A. Zinn. 2012. Feeding value of dried shredded sugarbeets as a partial replacement for steam-flaked corn in finishing diets for feedlot cattle. J. Anim. Sci 90: in press
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: White corn evaluation Four Holstein steers (137 kg) with cannulas in the rumen and proximal duodenum were used in a 4x4 Latin square design to evaluate the influence of processing method on comparative digestion of white corn. Treatments consisted of a basal finishing diet containing 80% corn grain (DM basis) as: 1) dry-rolled white corn, 2) steam-flaked white corn, 0.36 kg/L flake density, 3) steam-flaked white corn, 0.31 kg/L flake density, and 4) steam-flaked yellow corn, 0.31 kg/L flake density. Surfactant supplementation and fat digestion in Holstein steers Four Holstein steers (271kg) with cannulae in the rumen and proximal duodenum were used to study the influence of method of surfactant (Tween 80) supplementation on characteristics of digestion and feeding value of fat. Treatments consisted of a steam-flaked corn-based finishing diet supplemented with: 1) no supplemental fat, no surfactant; 2) 6% supplemental fat (yellow grease, no surfactant; 3) 5.75% supplemental fat plus 0.25% Tween 80 added to the diet as part of the premix (surfactant was mixed with premix before incorporation with grain in the mixer, as second step in diet preparation), and 4) 5.75% supplemental fat plus 0.25% surfactant combined directly with the supplemental fat (surfactant was mixed with supplemental fat before incorporation into the feed 56 mix as penultimate step in diet preparation). Fungal infested corn evaluation Four Holstein steers (407 kg) with cannulas in the rumen and proximal duodenum were used in a 4 X 4 Latin Square design experiment. Treatments consisted of a 755 g/kg steam-flaked corn-based finishing diet in which fungal infested steam-flaked corn replaced 0, 150, 300, and 450 g/kg of the control flaked corn. The yeast and mold counts averaged 290, and 12,000/g, respectively, for control flaked corn, and 700,000, and 6,200,000 CFU/g, respectively, for fungal infested flaked corn. PARTICIPANTS: Three visiting scholar (Jaime Salinas, Ruben Barajas, and Luis Corona), eight students ( Angel Arrizon, Ramses Carrasco, Rosa Bermudez, Horacio Davila, Dixie May, Alejandro Gonzalez, Alfredo Estrada, Jose Macias) and nine collaborating scientist (Enrique Alvarez , Alberto Barreras, Fernando Calderon, Victor Gonzalez, Martin Montano , Alejandro Plascencia, Miguel Cervantes, Noemi Torrentera, and Alberto Barreras) from UABC, Mexicali, Mexico (the UABC campus is located about 10 miles south of the UC, DREC research facility where this work is conducted). TARGET AUDIENCES: Research is designed to enhance knowledge, and address practical immediate concerns regarding nutrition, management and health of feedlot cattle, particularly the calf-fed Holstein. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
White corn evaluation: Characteristics of ruminal, postruminal and total tract digestion of OM, starch, and N were similar steam-flaked yellow and white corn treatments. Decreasing flake density of white corn did not affect ruminal OM digestion, but increased total tract OM digestion. Compared with dry rolling, steam flaking white corn increased ruminal, postruminal and total tract OM digestion, reflecting corresponding increases in ruminal, postruminal and total tract starch digestion. Apparent postruminal and total-tract N digestion also were greater for steam-flaked white corn than for dry rolled white corn. The DE value of steam-flaked white and yellow corn were similar. Compared with dry rolling, steam flaking markedly enhances the feeding value of white corn, optimal flake density being less than 0.36 kg/L. Although white corn has greater vitreous endosperm content, characteristics of ruminal starch digestion and UIP are similar to conventional yellow dent corn when processed to a similar flake density (0.31 kg/L). However, postruminal and total tract starch digestion tends to be slightly lower for flaked white corn than for yellow corn. Surfactant supplementation and fat digestion: There were no surfactant by supplemental fat interactions. Surfactant did not affect site and extent of OM, starch, N, ADF, and fatty acid digestion, or DE value of diet. Supplemental fat decreased ruminal and total tract digestion of OM and ADF and increased the DE value of diet. The decrease in postruminal FA digestion was mainly due to decreased digestion of C18:0. Digestible energy of supplemental fat averaged 6.87Mcal/kg. Independent of method of addition, supplementing high-fat diets with surfactant Tween 80 does enhance intestinal digestion of fat in Holstein steers fed a high-fat finishing diets. Fungal infested corn. There were no treatment effects on ruminal pH or volatile fatty acids molar proportions. Ruminal digestion of organic matter, and feed N decreased with increasing levels of fungal infested flaked corn in the diet. There were no treatment effects on net microbial N synthesis. Total tract digestion of OM, N and energy decreased with increasing fungal infested corn. Ruminal and total tract digestion of ADF and starch were not affected by treatments. It is concluded that mold infestation diminishes the feeding value of steam-flaked corn. The consequence was not related to effects of fungal growth on characteristics of digestion, but rather, to loss of readily digestible nutrients (starch) through the spoilage process, and to a lesser extent, decreased N digestibility.
Publications
- A. Plascencia, R. M. Bermudez, M. Cervantes, L. Corona, H. Davila-Ramos, M. A. Lopez-Soto, D. May, N. G. Torrentera, and R. A. Zinn. 2011. Influence of processing method on comparative digestion of white corn versus conventional steam-flaked yellow dent corn in finishing diets for feedlot cattle. J. Anim. Sci. 89:136-141.
- H. Davila-Ramos, A. Gonzalez-Castellon, A. Barreras-Serrano, A. Estrada-Angulo, M.A. Lopez-Soto, J.V. Macias-Zamora, A. Plascencia, S. H. Vega, R.A. Zinn. 2011. Influence of method of surfactant supplementation on characteristics of digestion and feeding value of fat in Holstein steers fed a high-energy finishing diet. J. of Appl. Anim. Res.39: in press
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Dried sugar beet evaluation Trial 1. Sixty calf-fed Holstein steer (475 kg) were used in a 96--d trial to evaluate the comparative feeding value of sun-dried chopped sugar beet roots with respect to growth performance, dietary NE, and carcass characteristics. Treatments were: 0, 20, and 40% sugar beets (DM basis). Sugar beets replaced steam-flaked corn in the finishing diet. Steers were blocked by weight and assigned within weight grouping to 15 pens (4 steers/pen). Fresh feed was provided twice daily. Trial 2. Six Holstein steers with cannulas in the rumen and proximal duodenum will be used in a replicated 3 x 3 Latin square experiment to evaluate treatment effects on digestive function. This study is completed and a manuscript is being prepared for submission for publication in the J Anim Sci. Zilpaterol effects on Holstein meat quality Three hundred-twenty Holstein steers (8 steers/pen) were used to determine the effects of feeding Zilpaterol hydrochloride at 7.56 g/ton (100% DMB) during the final 20 30 and 40 days of the feeding period on feedlot carcass characteristics and meat quality. Results of the study were published in J. Anim. Sci, and J Food Protection. Oyster Shell and limestone as potential alkalizing agents Four Holstein steers with ruminal and duodenal cannulas were used in a 4 x 4 Latin square design to evaluate ground oyster shell and limestone as ruminal alkalizing agents. Dietary treatments consisted of a steam-flaked corn finishing diets supplement with either oyster shell or limestone to provide dietary Ca levels of 0.50 (NRC 1996 calcium requirement) vs. 0.90% in a 2 x 2 factorial arrangement. Results of this study were published in In Experiment 2, ninety-six heifers (354 kg) were used in a 149-d finishing trial to evaluate oyster shell and limestone as Ca sources at dietary Ca levels of 0.50 vs. 0.9%, in a 2 x 2 factorial arrangement. In Experiment 3, four steers (399 kg) with cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design to evaluate treatment effects on characteristics of digestion. Results of this study were published in J. Anim. Vet. Advances PARTICIPANTS: One visiting scholars (Jaime Salinas), Four students ( Angel Arrizon, Jose Lenin, Eduardo Ponce, and Ulises Sanchez) and six collaborating scientist (Enrique Alvarez , Alberto Barreras, Fernando Calderon, Victor Gonzalez, Martin Montano , Alejandro Plascencia, and Noemi Torrentera) from UABC, Mexicali, Mexico (the UABC campus is located about 10 miles south of the UC, DREC research facility where this work is conducted). TARGET AUDIENCES: The target audience is the feedlot cattle industry. Research is designed to enhance knowledge, and address practical immediate concerns regarding nutrition, management and health of feedlot cattle, particularly the calf-fed Holstein. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Dried sugar beets. Substitution of steam-flaked corn with chopped dried sugar beets did not affect ADG or carcass quality. The NE value of the dried beet was 2.15 and 1.48 Mcal/kg for maintenance and gain, respectively (comparable to wheat grain). At current market prices (raw beets priced as sold to sugar factory), the use of dried sugar beet would save feeders $39/ton as compared with local corn grain. Oyster shell and limestone as alkalizing agents. Notwithstanding the greater reactivity of oyster shell vs. limestone, increasing supplemental levels of these alkalizing agents beyond that required to meet Ca requirements for maintenance and tissue growth had minimal effects on ruminal pH and digestive function. Zilpaterol effects on Holstein meat quality. Results illustrate that supplementation with the beta agonist zilpaterol in diets for calf-fed Holstein steers during the final 20 to 40 d on feed has minimal effects on purge, thaw, or cooking loss. Percentage of intramuscular fat will decrease, especially when fed for longer durations. Steaks from zilpaterol treated steers were less tender than steaks from control animals at all aging times, but treatment effects were ameliorated following postmortem aging.
Publications
- J. Salinas-Chavira, J. Lenin, E. Ponce, U. Sanchez, N. Torrentera, and R. A. Zinn. 2009. Comparative effects of virginiamycin supplementation on characteristics of growth-performance, dietary energetics, and digestion of calf-fed Holstein steers. J Anim Sci 2009 87: 4101-4108.
- Edrington, T. S. Farrow, R. L. Loneragan, G. H. Ives, S. E. Engler, M. J. Wagner, J. J. Corbin, M. J. Platter, W. J. Yates, D. Hutcheson, J. P. Zinn, R. A. Callaway, T. R. Anderson, R. C. Nisbet, D. J. 2009. Influence of beta -agonists (ractopamine HCl and zilpaterol HCl) on fecal shedding of Escherichia coli O157:H7 in feedlot cattle. Journal of Food Protection. 2009. 72: 12, 2587-2591
- Holmer, S. F. Fernandez-Duenas, D. M. Scramlin, S. M. Souza, C. M. Boler, D. D. McKeith, F. K. Killefer, J. Delmore, R. J. Beckett, J. L. Lawrence, T. E. VanOverbeke, D. L. Hilton, G. G. Dikeman, M. E. Brooks, J. C. Zinn, R. A. Streeter, M. N. Hutcheson, J. P. Nichols, W. T. Allen, D. M. Yates, D. A. 2009. The effect of zilpaterol hydrochloride on meat quality of calf-fed Holstein steers. Journal of Animal Science. 2009. 87: 11, 3730-3738.
- Zinn, R. A. Salinas-Chavira, J. Lenin, J. Montano, M. F. Sanchez, U. 2009. A comparison of ground oyster shell and limestone as potential alkalizing agents when fed at extra-nutritional levels for enhancement of growth-performance and digestive function in feedlot cattle fed steam-flaked corn-based finishing diets. Journal of Animal and Veterinary Advances. 2009. 8: 6, 1116-1123.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: DDG evaluation Trial 1. One hundred forty-four Holstein steer calves (112 kg) were used in a 305-d trial to evaluate the comparative feeding value of distillers dried grains plus soluble (DDG) with respect to growth performance, dietary NE, and carcass characteristics. Treatments were: 0, 10, 20, and 30% DDG (DM baisis). DDG replaced steam-flaked corn in the growing-finishing diet. Steers were blocked by weight and assigned within weight grouping to 24 pens (6 steers/pen). Fresh feed was provided twice daily. Trial 2. Four Holstein steers with cannulas in the rumen and proximal duodenum will be used in a 4 X 4 Latin square experiment to evaluate treatment effects on digestive function, including the metabolizable protein and amino acid value of DDG. This study is completed and a manuscript is being prepared for submission for publication in the Journal of Animal Science. Virginiamycin evaluation Four Holstein steers with cannulas in the rumen and proximal duodenum will be used in a 4 X 4 Latin square experiment to evaluate the influence of virginiamycin supplementation on digestive function. Treatments consisted of a steam-flaked corn-based growing-finishing diet supplemented with: 1) no antibiotic (control); 2) 16 ppm virginiamycin; 3) 22.5 ppm virginiamycin; and 4) 28 ppm monensin (positive control). Findings of this study were presented at the 2008 National meetings of the American Society of Animal Science. A manuscript was submitted to the Journal of Animal Science. Jersey steer growth-performance evaluation Eighty Jersey steer calves (101 kg) were used in a 383-d trial to evaluate the influence of dietary energy density on growth performance, dietary NE, and carcass characteristics. Treatments consisted of steam-flaked corn-based growing and finishing diets supplemented with 12 vs. 24% forage (DM basis. Steers were blocked by weight and assigned within weight grouping to 16 pens (5 steers/pen). Fresh feed was provided twice daily. PARTICIPANTS: Two visiting scholars (Ruben Barajas and Leopoldo Flores) and six collaborating scientist (Fernando Calderon, Victor Gonzalez, Alejandro Plascencia, Noemi Torrentera, Martin Montano, and Enrique Alvarez) from UABC, Mexicali, Mexico (the UABC campus is located about 10 miles south of the UC, DREC research facility where this work is conducted). TARGET AUDIENCES: The target audience is the feedlot cattle industry. Research is designed to enhance knowledge, and address practical immediate concerns regarding nutrition, management and health of feedlot cattle, particularly the calf-fed Holstein. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
DDG Substitution of DDG for steam-flaked corn enhanced 305-d ADG. The improvement was most pronounced at the 20% level of substitution where ADG was enhanced 5.3%. This improvement was especially apparent during the initial 126 d of the feeding period, probably reflecting the replacement value of DDG as a source of UIP in addition to NE. There were no treatment effects on 305-d DMI or gain efficiency. During the initial 126-d period DDG substitution markedly enhanced gain efficiency, again being optimal at the 20% level of replacement. However, subsequently the response diminished, and during the late finishing phase substitution of DDG for steam-flaked corn diminished gain efficiency. DDG substitution did not affect dressing percentage, fat thickness or yield grade, but increased KPH, marbling score, and LM area. DDG substitution decreased (linearly) ruminal digestion of OM and N, and total tract digestion of OM. DDG substitution tended to increase apparent total tract digestion of N. Results of the metabolism study reinforce the extracaloric value of DDG during the early growing phase (first 126 d) as a consequence of helping to meet the steers metabolizable amino acid requirements. Virginiamycin There were no treatment effects on ruminal digestion of OM, NDF, starch and N, and microbial efficiency. Virginiamycin increased ruminal N efficiency. Virginiamycin supplementation did not affect postruminal and total tract digestion of OM, starch, NDF, and N. In contrast, monensin supplementation depressed total tract digestion of OM (4.2%) and NDF (29.5%). Ruminal lactic acid concentration was low, accounting for only 1.4% of total organic acids, and not affected by treatments. Variation in ruminal pH was associated with ruminal organic acid molar concentration. There were no treatment effects on ruminal VFA molar concentration. We concluded that virginiamycin supplementation effects on site and extent of nutrient digestion are minimal, and do not explain the marked enhancements in feedlot growth-performance and dietary energetic efficiency of calf-fed Holstein steers observed in the feedlot growth-performance trial. Jersey steer growth-performance Growth-performance of calf-fed Jersey steers was evaluated during a 383-d growing-finishing phase. A challenge for the smaller frame Jersey is its very low rate of gain (0.96 vs 1.58 kg per day for Holstein steers), and hence poor gain efficiency (0.156 vs .202 kg ADG per kd DMI for Holstein steers). Increasing dietary forage level from 12% to 24% decreased ADG (4.2%), gain efficiency (7.4%) and dietary NEm (6.2%). The decrease in dietary NE was in close (99.9%) agreement with expected due to energy dilution of the diet. However, consistent with our previous trial, steers consumed 15% more feed than was expected for the observed weight gain. Initial weight of calves entering the feedlot had a pronounced effect on growth performance. This study describes Jersey growth characteristics and their relationship to ultimate carcass traits and economics.
Publications
- Plascencia, A. N. G. Torrentera, and R. A. Zinn. 2008. Influence of the Beta -Agonist, Zilpaterol, on Growth Performance and Carcass Characteristics of Feedlot Steers. J. Anim. Vet. Adv. 7 (10): 1257-1260.
- Barajas, R., E. G. Alvarez, M. F. Montano and R. A. Zinn. 2008. Influence of day-to-day fluctuations in feed intake on feedlot cattle growth-performance and digestive function. J of Anim and Vet Adv. 7:716-821.
- Montano, M. F., L. R. Flores, J. F. Calderon, V.M. Gonzalez, J. Salinas, and R. A. Zinn. 2008. Influence of level of addition on the feeding value of cane molasses in growing-finishing diets for feedlot cattle. J. Anim and Vet Adv. 8:190-194.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: One hundred forty-four Holstein steer calves (119 kg) were used in a 340-d trial to evaluate effects of virginiamycin supplementation on growth performance, dietary NE, and carcass characteristics. Treatments were: Control (no antibiotic) 2) 16 ppm virginiamycin; 3) 22.5 ppm virginiamycin; and 4) 28 ppm monensin (positive control). Calves received a steam-flaked corn-based growing diet, formulated to meet average nutrient requirements for the first 112 d , and thereafter were fed a finishing diet formulated to meet average nutrient requirements from d 112 until slaughter. Steers were divided into two weight groups (light and heavy) assigned within weight grouping to 24 pens (6 steers/pen). Fresh feed was provided twice daily. Virginiamycin supplementation did not affect (P > 0.10) ADG, but increased (linear component, P = .03) 340-d gain efficiency. Improvement in gain efficiency is largely attributable to enhanced energetic efficiency (linear component, P = 0.06).
Improvements in dietary NE were most pronounced during the final 116 d of the feeding period (linear component, P = 0.06) that comprised the hot summer months (June through September). Monensin supplementation did not affect (P > 0.10) growth performance. There were no treatment effects (P > 0.10) on carcass dressing percentage, KPH, fat thickness, and marbling score. Virginiamycin supplementation increased (linear component, P = 0.07) LM area. Monensin supplementation also increased (P = 0.10) LM area. Both virginiamycin (linear component, P = 0.01) and monensin (P = 0.03) supplementation reduced morbidity. However, there were no dietary treatment effects (P > 0.10) on mortality. Although average initial weight for the light and heavy grouping differed by only 4 kg, the "heavy" grouping had greater ADG (4.3%, P = 0.03), and gain efficiency (2.3%, P = 0.10). The improvement in gain efficiency was due largely to increased (3.2%, P = 0.02) dietary NE. The heavy weight group had greater
carcass weight (3.7%, P = 0.04), and LM area (5.4%, P = 0.003). Morbidity tended to be greater (P = 0.12) in the heavy group. We concluded that virginiamycin (an antibiotic that limits ruminal lactic acid production) will markedly enhance feedlot growth-performance and dietary energetic efficiency of calf-fed Holstein steers. As has been noted in poultry and swine studies, virginiamycin supplementation had a notable beneficial effect on growth performance and energetic efficiency of calves during the late finishing phase, a period of heat stress. Calves that are lighter than group average for initial weight will have slightly slower growth rates as well as slightly reduced dietary energetic efficiency. Four Holstein steers with cannulas in the rumen and proximal duodenum will be used in a 4 x 4 Latin square experiment to evaluate treatment effects on digestive function. This trial is not yet completed.
PARTICIPANTS: Participants in this project include a student intern (Cristina Hough), a MS student (Eduardo Ponce), two Ph D students (Jose Lenin and Ulises Sanchez), a visiting scholar (Leopoldo Flores) and five collaborating scientist (Alejandro Plascencia, Noemi Torrentera, Martin Montano, Alberto Barreras, and Enrique Alvarez) from UABC, Mexicali, Mexico (the UABC campus is located about 10 miles south of the UC, DREC research facility where this work is conducted).
TARGET AUDIENCES: The target audience is the feedlot cattle industry. Research is designed to enhance knowledge, and address practical immediate concerns regarding nutrition, management and health of feedlot cattle, particularly the calf-fed Holstein.
PROJECT MODIFICATIONS: No major modification.
Impacts
Digestive disfunctions are primary causes of lost performance in calf-fed Holsteins. Due to their very large frame size and mature weight, Holstein steers are maintained on very high concentrate growing-finishing diets throughout the feedlot period (330 to 360 d). This greatly increases the probability of occasional subacute ruminal lactic acidosis. Virginiamycin is an antibiotic that has been shown to inhibit growth of ruminal lactic acid producing bacteria. This study is the first attempt at evaluating the efficacy of supplementing with virginiamycin as a tool to limit subacute acidosis and promote growth in calf-fed Holstein steers. The results thus far are very promising. Assuming a feed cost of $230/ton, the improvement in gain efficiency by supplementing with 22.5 ppm of virginiamycin was $29.43/steer.
Publications
- Rosales Lopez, J., M. F. Montano Gomez, A. Plascencia Jorquera, J. Salinas Chavira, R. A. Zinn. 2007. Dietary Phosphorus Requirement of Holstein Steers During Early Growing Period. J. Appl. Anim. Res. 31:113-115.
- Plascencia, A., M. A. Lopez-Soto, M. F. Montano, J. G. Serrano, R. A. Ware, and R. A. Zinn Influence of surfactant supplementation and maceration on the feeding value of rice straw in growing-finishing diets for Holstein steers. J Anim Sci. 2007 85: 2575-2581.
- Plascencia A., E. Alvarez, and R.A. Zinn. 2007. Influence of Intraruminal Infusion of Acetate on Ruminal Characteristics and NDF Digestion in Feedlot Steers. J. Anim. Vet. Adv.8:986-990.
- R. A. Zinn, A. Barreras, L. Corona, F. N. Owens, and R. A. Ware. 2007. Starch digestion by feedlot cattle: Predictions from analysis of feed and fecal starch and nitrogen. J. Anim. Sci. 85:1727-1730.
- Alvarez, E. G., and R. A. Zinn. 2007. Influence of Site of Casein Infusion on Voluntary Feed Intake and Digestive Function in Steer Calves Fed a Sudangrass-Based Growing Diet. J. Anim. Vet. Adv. 6:249-256.
- Zinn, R. A., E. G. Alverez, M. Montano, and J. Salinas-Chavira. 2008. Influence of dry rolling and tempering agent addition during the steam-flaking of sorghum grain on the feeding value for feedlot cattle. J. Anim. Sci. jas.2007-0491v1
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Progress 01/01/06 to 12/31/06
Outputs
One hundred ninety-two Holstein steer calves (139 kg) were used in a 331-d trial to evaluate effects of direct-fed microbial supplementation (combination of Propionibacterium freudenreichii and Lactobacillus acidophilus; Bovamine, Nutrition Physiology Corp., Guymon, OK) on growth performance and carcass characteristics. Treatments were: Control (no microbial) 2) 105 NP51 + 109 NP24 /hd/d; 3) 106 NP51 + 109 NP24 /hd/d; 4) 107 NP51 + 109 NP24. Calves received a steam-flaked corn-based growing diet, formulated to meet average nutrient requirements for the first 112 d , and thereafter were fed a finishing diet formulated to meet average nutrient requirements from d 112 until slaughter. Steers were blocked by weight and assigned to 32 pens (6 steers/pen). Fresh feed was provided twice daily. Daily supplementation with 105 NP51 + 109 NP24 (treatment 2) increased ADG (4.6%, P < 0.05) during the first half of the trail (168 d) and tended to increase ADG (4.5%, P = 0.27)
during the last 163 d. Overall, treatment 2 increased ADG 4.6% (P < 0.05). Treatments 2 and 3 did not affect (P > 0.20) ADG. There were no treatment effects (P > 0.20) on DMI, gain efficiency, and dietary NE, although all were numerically greater for treatment 2. Treatment effects on carcass characteristics are not yet available. We concluded that supplementation with direct fed microbial may enhance ADG in calf-fed Holstein steers.
Impacts
One hundred eight Holstein steer calves (229 kg) were used in a 264-d trial to evaluate effects of dietary supplementation with antibodies (RMT; Camas Inc., Le Center, MN) against S. bovis, clostridial, and coliform bacteria on growth performance and carcass characteristics. Calves were fed a steam-flaked corn-based growing-finishing diet. Treatments were 0, 3.5 and 7 mL/hd/d of RMT added to the complete mixed feed. Steers were blocked by weight and assigned to 18 pens (6 steers/pen). Fresh feed was provided twice daily. There were no treatment effects (P > 0.20) on ADG, DMI, gain efficiency, and observed versus expected dietary NE, averaging 1.34, 8.09, 0.165, and 0.997, respectively. There was no apparent digestive dysfunction or morbidity during the course of the trial, possibly explaining the lack of response to treatments.
Publications
- Ware, R. A., Calderon, J. F., Corona, L., and Zinn, R. A. 2005. Case study: comparative feeding value of rice straw in growing-finishing diets for calf-fed Holstein steers: fibrolytic enzyme supplementation. Professional Animal Scientist. 21(5): 416-419.
- Lopez, M. A., E. A. Gonzalez, A. B. Serrano, V. M. Gonzalez, D. M. Garcia, A. Plascencia, and R. A. Zinn. 2006. Influence o fan exogenous fibrolytic enzyme and the maceration process of a lw-quality forage on digestion and ruminal function of dry Holstein cows. Vet. Mex. 37:275-289.
- Corona, L., F. N. Owens, and R. A. Zinn. 2006. Impact of corn vitreousness and processing on site and extent of digestion by feedlot cattle. J. Anim. Sci. 84:3020-3031.
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Progress 01/01/05 to 12/31/05
Outputs
One hundred eight Holstein steer calves (114 kg) were used to evaluate effects of phase feeding metabolizable protein (MP) on growth performance and carcass characteristics. Three strategies were evaluated : 1) from d 1 to finish calves received a steam-flaked corn-based growing-finishing diet, formulated to meet average MP requirements for the 351 d feeding period (urea was the sole source of supplemental N); 2) from d 1 to d 112 steers received a starter diet formulated to meet MP requirements during the initial 112-d feeding period (3.5% fishmeal and 7% canola were source of supplemental N), and thereafter were fed diet 1; 3) from d 1 to d 56 steers received a starter diet formulated to meet the MP requirements during the initial 56-d feeding period (5% fishmeal and 10% canola were source of supplemental N), from d 56 to d 112 steers were fed a diet formulated to meet the MP requirements during the subsequent 56-d period (2.5% fishmeal and 5% canola were source of
supplemental N) and thereafter, steers were fed diet 1. Steers were blocked by weight and assigned to 18 pens (6 steers/pen). Fresh feed was provided twice daily. Differences between phase-feeding strategies (treatments 2 vs 3) on growth-performance were small (P > 0.20). However, compared with control, phase feeding to meet metabolizable amino acid requirements increased ADG (18%, P < 0.01), DMI (4%, P < 0.05), and observed/expected dietary NE (16%, P < 0.01) during the first 112 d of trial. Overall (1-351 d), phase feeding increased ADG (6%, P < 0.01), DMI (4%, P < 0.10), gain efficiency (3%, P < 0.05), and observed/expected dietary NE (4%, P < 0.01). Phase-feeding increased hot carcass weight (5%, P < 0.01), dressing percentage (1%, P < 0.10), fat thickness ( 25%, P < 0.05), and longissimus area (9%, P < 0.05). The first limiting metabolizable amino acid for the control treatment (estimated based on observed DMI; NRC, 2000, level 1) during the initial 112 d were MET, LYS, and HIS.
Whereas, with the phase feeding treatments metabolizable amino acids were marginally deficient only during the first 56-d on feed. We concluded that formulating starting diets to meet the average metabolizable amino acid requirements during the initial 112 d on feed will appreciable enhance overall growth-performance of calf-fed Holstein steers.
Impacts
Holsteins calves are typically fed a single diet throughout the entire growing-finishing period. This diet usually contains between 12 and 13% crude protein, using urea as the sole source of supplemental N. Based on NRC(1996) Level-1 model, this conventional diet meets the average metabolizable protein requirements across the overall (roughly 360-days) feeding period. However, it does not supply metabolizable amino acid requirements of calves during the initial growing phase (112 to 140 days; NRC, 1996; Zinn and Shen, 1998). This study demonstrates that formulating to meet the average metabolizable amino acid requirements during the first 112 day on feed will have an appreciable impact on daily weight gain and energetic efficiency calf-fed Holstein steers.
Publications
- Alvarez, E.G., A. Plascencia and R.A. Zinn. 2005. Partial substitution of alfalfa hay with grass hay (Sudangrass, Elephant Grass) in diets for lactating dairy cattle: Dry Matter intake, lactation performance and digestive function. . J. of Anim. and Vet. Adv. 4:448-452.
- Corona L., A. Plascencia, R. A. Ware, and R. A.Zinn. 2005. Comparative feeding value of palmitate as a substitute for conventional feed fat in cattle. J. of Anim. and Vet. Adv. 4:247-253.
- Corona L., S. Rodriguez, R.A. Ware and R.A. Zinn. 2005. Comparative effect of whole, ground, dry-rolled and steam-flaked corn on digestion and performance in feedlot cattle. Prof. Anim. Sci. 21: 200-206. 2005.
- Plascencia, A., G.D. Mendoza, C. Vazquez, and R.A. Zinn. 2005. Factores que influyen en el valor nutrimental de las grasas utilizadas en las dietas para bovinos de engorda en confinamiento: Una revision. INTERCIENCIA. 30:134-142.
- Torrentera, N.and R.A Zinn. 2005. Predicting Carcass Dressing Percentage in Feedlot Bulls and Heifers. Journal of Animal and Veterinary Advances 4 (7): 663-665
- Ware, R. A., N. Torrentera, and R. A. Zinn. 2005. Influence of Maceration and Fibrolytic Enzymes on the Feeding Value of Rice Straw. J. Anim. and Vet. Sci. Vol. 4(3): 387-392.
- Ware, R. A., L. Corona, N. torrentera, and R. A. Zinn. 2005. Effect of pelletizing on the feeding value of rice straw in steam-flaked corn growing-finishing diets for feedlot cattle. Animal-Feed-Science-and-Technology.; 107: In Press
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Progress 01/01/04 to 12/31/04
Outputs
Ninety-six calf-fed Holsteins (264 +/- 2.8 kg) were used to evaluate effects of delay-implant strategies on growth performance and carcass traits. Calves were purchased as steers (castrated via elastration). They originated from Tulare, California. Treatments were: 1) control (non implanted from birth); 2) implanted with Revalor-S at 264 kg BW; 3) implanted with Rrevalor-S at 295 kg BW and 4) implanted with Revalor -S at 327 BW. All implanted cattle were reimplanted with Revalor-S 90 d before anticipated slaughter date. Results show that implanting increased ADG (9%), NEm (7 %), and longissimus muscle area (9%). Growth performance response was optimal when calves received their first implant at 295 kg BW.
Impacts
Hormonal implants are administered to cattle to augment growth and delay fat deposition. Holsteins are a late-maturing breed of cattle that are placed on high energy diets from birth. Previous studies showed that response to growth implants was appreciable when Holsteins weighed more than 250 kg. This study demonstrates that optimal response is obtained when Holsteins are first implanted at 295 kg. Based on current practices, delay implanting will save producers from $2.5 to $6.00 per head.
Publications
- Zinn, R. A., R. Barrajas, M. Montano, and R. A. Ware. 2003. Influence of dietary urea level on digestive function and growth performance of cattle fed steam-flaked barley-based finishing diets. J. Anim. Sci. 81:2383-2389.
- Plascencia,A., G. D. Mendoza, C. Vasquez, and R. A. Zinn. 2003. Relationship between body weight and level of fat supplementation on fatty acid digestion in feedlot cattle. J. Anim. Sci. 81:2653-2659.
- Zinn, R. A., A. Plascencia. 2004. Influence of level and method of supplementation on the utilization of supplemental fat by feedlot steers. J. Anim. Vet. Advances 3:470-474.
- Alvarez, E. G., J. F. Calderon, M. F. Montano, R. A. Ware, and R. A. Zinn. 2004. Influence of dietary forage level on digestive function and growth performance in cattle fed steam-flaked corn-based growing -finishing diets. 2004. J. Anim. Vet Advances. 3:503-509.
- Plascencia, G. D., C. Mendoza, C. Vasquez, and R. A. Zinn. 2004. Influence of levels of fat supplementation on bile flow and fatty acid digestion in cattle. J. Anim. Vet Advances. 3:763-768.
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Progress 01/01/03 to 12/31/03
Outputs
One hundred eight Holstein steer calves (127 kg) were used to evaluate phase feeding metabolizable protein (MP). Three strategies were evaluated:1) from d 1 to finish calves receive a steam-flaked corn-based growing-finishing diet formulated to meet average MP requirements for the 322 d feeding period (urea was the sole source of supplemental N); 2) calves received starter-grower diets formulated to meet the average MP requirements for each of the first and second 56-d periods; 3) calves received a grower diet formulated to meet the average MP requirements for the first 112-d feeding period. After 112 d on feed all calves received Treatment 1. Calves were blocked by weight and assigned to 18 pens (6 steers/pen). Fresh feed was provided twice daily. This trial is still in progress. During the initial 56-d period there were no treatment effects on DMI. Daily weight gain averaged 1.39, 1.64, and 1.65 kg/d for treatments 1 through 3, respectively. These results are
similar to the previous years study where it was observed that phase feeding to meet MP requirements during the initial 112 d enhanced growth performance during that phase, although the long-term or carryover benefit was not appreciable.
Impacts
Feeding Holstein calves to satisfy metabolizable amino acid requirements during the initial 56 d on feed will enhance daily weight gain by 19 uring that phase.
Publications
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Progress 01/01/02 to 12/31/02
Outputs
Two hundred sixteen Holstein steers (114 kg) were used to evaluate phase feeding metabolizable protein (MP). Four strategies were evaluated: 1) from d 1 to finish steers received a steam-flaked sorghum-based growing-finishing diet, formulated to meet average MP requirements for the 322 d feeding period (urea was the sole source of supplemental N); 2) from d 1 to d 56 steers received a starter diet formulated to meet the MP requirements during the initial 56-d feeding period (10% fishmeal), and thereafter were fed diet 1; 3) from d 1 to d 112 steers received a starter diet formulated to meet MP requirements during the initial 112-d feeding period (6.5% fishmeal), and thereafter were fed diet 1; and 4) from d 1 to d 168 steers received a starter diet formulated to meet MP requirements during the initial 168-d feeding period (4% fishmeal), and thereafter were fed diet 1. Steers were blocked by weight and assigned to 36 pens (6 steers/pen). Fresh feed was provided twice
daily. During the initial 168 d of the trial, increasing duration of the starter phase (0, 56, 112, and 168 d) increased ADG (6%, linear component, P < .01), gain efficiency (8%, quadratic component, P < .01), and dietary NE (6%, linear component, P < .01), and decreased hip height:weight ratio (5%, linear component, P < .01). However, across the entire 322-d feeding period, treatment effects on growth performance were null (P > .10). We conclude that although phase feeding to meet MP requirements during a particular growing phase will enhance growth performance during that phase, the long-term or carryover benefit may be non-appreciable.
Impacts
Although phase feeding calf-fed Holstein steers to meet metabolizable protein requirements during the early growing phase (initial 168 d on feed) will enhance growth performance during that phase, the long-term (>280-d) or carryover benefit may be non-appreciable.
Publications
- M. Machado, Calderon, J.F. and Zinn, R.A. 2002. Phase feeding strategies to meet metabolizable protein requirements of calf-fed Holstein steers. Western Section Vol, 53, 2002.
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Progress 01/01/01 to 12/31/01
Outputs
Summary: Growth characteristics of 255 calf-fed Holstein steers were evaluated. Initial and final shrunk weight averaged 119 and 574 kg, respectively. Carcass specific gravity (SG) decreased with increasing LW (SG = 1.0588 + .00014LW - .000000266LW2; R2 = .77). Empty body fat (EBF) increased in a near linear fashion with LW ( EBF, % = 12.01 + .000003LW2; R2 = .74). Hip height (HH, cm) was very closely associated with LW (LW, kg = 1720 - 34.2HH + .182HH2; R2=.994). However, the nature of the relationship did differ depending on growth implant strategy. For Holsteins that received no implant, the relationship was: LW, kg = 1448.58 - 29.08HH + .158HH2 (R2 = .993). For Holsteins that received a more intensive implant program (Synovex-C on arrival followed by Synovex-S on d-84, and Revalor-S on d-168, the relationship was: LW, kg = 1946.59 - 38.07HH + .199HH2 (R2 =.993). For Holsteins that were delay-implanted (first implanted on d-112 with Revalor-S and reimplanted on
d-196 with Revalor-S) the relationship was: LW, kg = 1783.25 - 35.72HH + .191HH2 (R2 =.995). In all cases, the relationship between HH and LW was similar until cattle reached approximately 140-d on feed. This similarity in HH:LW ratio for implanted and non-implanted calves supports the observation that benefits to implanting Holstein calves early are small. After the initial approximately 140-d in the feedlot, LW increases at a greater rate than HH. The HH:LW ratio is lower per unit weight for implanted steers than that of non-implanted steers, suggesting greater retail yield. Beginning at 160-d, the HH:LW ratio alone can explain 22 to 32 % of the variation in marbling score of Holsteins marketed at an average LW of 572 kg.
Impacts
Hip height of calf-fed Holstein steers is very closely associated with live weight. The hip height:weight ratio of Holsteins is not affected by growth implants until calves reach a live weight of about 300 kg. Thereafter, the nature of the relationship is affected appreciably by growth implants. The growth performance characteristics of Holsteins are consistent with that of other large-frame breeds. They can be taken to very heavy market weights without excessive finish. Although, calf-fed Holsteins will exhibit a high degree of intramuscular fat deposition at comparatively low levels of empty body fat.
Publications
- M. Machado, N. Torrentera, and R.A. Zinn. 2001. Relationship between hip height and live weight on growth characteristics and carcass composition of calf fed Holstein steers. Proc. West. Sect. Am. Soc. Anim. Sci. 52:479-482.
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Progress 01/01/00 to 12/31/00
Outputs
One hundred ninety-two crossbred steers (229 kg) were used evaluate the influence of metabolizable amino acid intake on growth performance and health during the initial 42-d receiving period. Treatments consisted of four levels of metabolizable lysine (23, 24, 25 and 26 g/kg diet DM). Morbidity averaged 36%, and was not affected (P > .20) by treatments. No steers died during the study. Increasing the metabolizable lysine supply increased DMI, ADG, gain efficiency, and dietary NE (linear effect, P < .01). Metabolizable amino acid supply of the basal diet was determined using 6 steers (214 kg) with cannulas in the rumen and proximal duodenum, the result was in very close agreement with expected (R squared = .99; P < .0001) based on NRC (1996) Level 1 model. The metabolizable amino acid supplies for treatments in Trial 1 were estimated by adding tabular metabolizable amino acid values for the supplemental proteins to the observed metabolizable amino acid supply of the
basal diet. Treatment effects on metabolizable lysine supply explained 99% of the variation (P < .01) in ADG, and 91% of the variation in observed versus expected dietary NE. The biological value of intestinal chyme was determined based on the chemical score ratio technique, using bovine tissue as the reference protein. Accordingly, methionine and lysine were closely co-limiting amino acids having ratios of 77 and 79%, respectively. We conclude that current NRC standards reliably predict both requirements and supplies of metabolizable amino acids for feedlot calves. Diet formulations that do not meet the metabolizable amino acid requirements may depress both ADG and the partial efficiency of utilization of metabolizable energy for maintenance and gain.
Impacts
Current NRC standards reliably predicted both requirements and supplies of metabolizable amino acids for feedlot calves. Diet formulations that do not meet the metabolizable amino acid requirements may depress both ADG and the partial efficiency of utilization of metabolizable energy for maintenance and gain.
Publications
- Machado, M.N., M.F. Montano, and R.A. Zinn. 2000. Metabolizable amino acid requirements of feedlot calves. Proc. West. Sect. Am. Soc. Anim. Sci. 51:469-472.
- Zinn R.A., E.G. Alvarez, M.F. Montano, and J.E. Ramirez. 2000. Interaction of protein nutrition and laidlomycin on feedlot growth performance and digestive function in Holstein steers. J. Anim. Sci. 781768-1778.
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Progress 01/01/99 to 12/31/99
Outputs
Two isonitrogenous diets (12.5% CP) containing 20% (20% NPN) vs 40% of the N as non-protein N (40% NPN) were evaluated across 0 vs 10 mg laidlomycin propionate (LP)/kg in a 2 x 2 factorial arrangement. Changes in dietary NPN:N ratio were developed by partial substitution of urea-N for fishmeal-N. In Trial 1, 4 Holstein steers (349 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on digestive function. Total tract OM digestion was slightly greater (1.2%, P < .10) for diets containing 20% of N as NPN, due to greater (3.4%, P < .05) postruminal OM digestion. Supplemental LP decreased passage of microbial N to the small intestine (7.4%, P < .10) and ruminal degradation of dietary CP (DIP, 8.1%, P < .10). Decreasing NPN:N ratio decreased microbial N flow to the small intestine (7.5%, P < .10) , DIP (15%, P < .01), and increased (6%; P < .05) the flow of indispensable amino acids to the small intestine. Supplemental LP increased
(P < .10) ruminal pH. There were no treatment effects (P > .10) on ruminal molar proportions of acetate and propionate. In Trial 2, 120 Holstein steers (122 kg) were used to evaluate treatment effects on growth performance. Decreasing the NPN:N ratio increased ADG (P < .01) by 36, 40, and 16%, respectively, for the initial three 56-d periods of the trial. Overall, ADG was 17% greater (P < .01) for cattle consuming diets containing 20 vs 40% NPN. Decreasing the NPN:N ratio increased (P < .01) gain efficiency by 17 and 14, respectively, for the initial two 56-d periods. Overall, gain efficiency was 6% greater (P < .01) for diets containing 20% NPN. Dietary NPN:N ratio did not influence (P > .10) the NE value of diets. Supplemental LP did not affect DMI (P > .10), but increased ADG (6%, P < .01) and gain efficiency (5%, P < .05), and decreased (11%, P < .05) the maintenance energy requirements. Protein nutrition limited growth performance of calves receiving the 20% NPN diets during the
initial 112 d of the trial. With the 40% NPN diets, protein nutrition limited growth performance throughout most of the trial (d 1 to d 224). We conclude that LP will enhance daily weight gain and gain efficiency of calf-fed Holstein steers. Conventional urea-based diets will not diminish response to LP, although they may not meet the metabolizable amino acid requirements of calf-fed Holsteins during the first three quarters of the feeding period.
Impacts
Meeting metabolizable amino acid requirements will markedly enhance steer performance. The NRC (1996) level 1 model accurately predicts amino acid flow to the small intestine. Supplementation with laidlomycin decreases maintenance energy costs by 12%. Responses to laidlomycin are not diminished by use of diets containing urea as the sole source of supplemental N.
Publications
- No publications reported this period
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