Source: LOUISIANA STATE UNIVERSITY submitted to
ENHANCING PRODUCTION AND REPRODUCTIVE PERFORMANCE OF HEAT-STRESSED DAIRY CATTLE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0187618
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
S-299
Project Start Date
Oct 1, 2000
Project End Date
Sep 30, 2005
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Project Director
Ward, J. D.
Recipient Organization
LOUISIANA STATE UNIVERSITY
202 HIMES HALL
BATON ROUGE,LA 70803-0100
Performing Department
SOUTHEAST RESEARCH STATION
Non Technical Summary
Dairy cattle have lower feed intake during periods of hot humid weather. This reduces production and reproductive performance lowering profitability of the dairy. This project will investigate the effects of heat stress on dairy cattle in a hot humid climate and develop nutritional and managment stategies to minimize the negative effects of heat stress on milk production, reproductive performance, profitability and heat tolerance of these animals.
Animal Health Component
60%
Research Effort Categories
Basic
40%
Applied
60%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3023410101040%
3063410106040%
3013410102020%
Knowledge Area
302 - Nutrient Utilization in Animals; 306 - Environmental Stress in Animals; 301 - Reproductive Performance of Animals;

Subject Of Investigation
3410 - Dairy cattle, live animal;

Field Of Science
1060 - Biology (whole systems); 1010 - Nutrition and metabolism; 1020 - Physiology;
Goals / Objectives
To further elucidate direct and indirect effects of chronic heat stress in a hot, humid climate on nutrient intake and metabolism, endocrine status, reproductive and lactational performance of dairy cattle. To develop physiological, nutritional and environmental stategies to enhance milk production, repoductive performance, profitability and heat tolerance of dairy cattle in a hot, humid climate.
Project Methods
The effects of the ambient environment and heat abatement methods on body temperature and subsequent intake, milk yield and composition and body weight changes will be determined in the high producing dairy cow during cool and hot weather (GA, LA, MO, NC). Each location will use similar management practices, heat abatement techniques and research protocols in the replicated trial. The effects of environmental conditions on body temperature will be compared to determine at what point heat stress occurs, which environmental variables or combinations of variables have the greatest impact on cow performance and if there are delayed effects of environmental conditions. Lactation performance will be evaluated using daily milk yield, milk composition analysis, and changes in body weight and condition. Reproductive performance will be evaluated by days to first breeding, services per conception, and pregnancy rate. Data for economic analysis will be collected using standardized protocols and coordinated by NC. Additional data on the effects of environment on the transition cow will be collected for cows calving in spring, summer and fall (GA, LA, NC, FL). Nutrient intake, body weight and condition score, body temperature, and blood metabolites (insulin, NEFA, beta-hydroxybutyrate, BUN, and progesterone) will be determined prepartum along with nutrient intake, milk yield and composition, health data, select endocrine concentrations, and reproductive performance postpartum using a shared research protocol. Replicated studies will be conducted during cool and hot weather using diets that vary in protein content and quality (AL, GA, LA, SC, NC). Production studies using a shared research protocol will be used to compare protein treatment effects on DMI, milk yield, efficiency of milk yield, and digestibility of dietary nutrients. Days to first service, services per conception, and pregnancy rate will be monitored to evaluate reproductive efficiency. Studies will be conducted to examine the use of very high DCAD diets, using combinations of K and Na to vary DCAD (GA, LA, NC). Researchers will use a standard experimental design for replicated trials. Response variables include DMI, milk yield, change in body weight and condition score, efficiency of production, days to first service, services per conception, and pregnancy rate. Data from each location will be compiled and results used to determine the effect of DCAD under heat stress conditions. Studies will be conducted to determine if feed additives will improve performance during periods of heat stress (AL, LA). Effects of these ingredients will be determined by measuring DMI, milk yield, change in body condition score and weight, efficiency of production and nutrient digestibility. Research will be coordinated by LA. When appropriate, shared protocols will be used to provide replication of treatments and data compiled for analysis.

Progress 10/01/00 to 09/30/05

Outputs
Over the period of this study both environmental and nutritional changes were studied to improve the performance of heat stressed dairy cattle during the transition period. The first nutritional change investigated was the use of increased dietary anion-cation difference (DCAD) and supplemental fat. DCAD was increased using a combination of sodium bicarbonate and potassium carbonate. Supplemental fat was added as megalac. The additives were incorporated into the grain mix which was fed seperately from forage. Increasing DCAD lowered grain intake but did not affect total DM intake. Supplemental fat had no effect on intake. Neither dietary treatment affected body condition changes or metabolic indicators of energy status. Milk production was also not affected by dietary treatment. One study investigated the effects of yeast culture and length of supplementation on transition cows during periods of heat stress. Three treatments were no yeast, yeast supplementation 21 d prior to calving through 21 d post-calving (short regimen), and yeast supplementation 21 d pre-calving through 56 d post-calving (long regimen). Yeast was fed at 56.7 g/d prior to calving and 113.4 g/d post-calving. The short regimen had no effect on DMI or milk production but the long regimen increased milk production. Beta-hydroxybutyrate (BHBA) was not affected by dietary treatment during the first 28 d but cows on the long regimen had lower BHBA on D56 than cows on the short regimen. One study investigated the effects of yeast supplementation and a fiber digestion enzyme on the production of mid to late lactation dairy cattle during heat stress. Neither dietary treatment had any affect on production. Two studies were conducted to determine the effects of supplemental cooling pre-partum on post-partum performance. In each study sprinklers and fans were compared to shade only. Supplemental cooling had no effect on milk production in either study. In one study DMI was depressed by pre-partum cooling and not affected in the second study. Body temperatures were decreased in one study but were unaffected in the other. In one study milk fat was increased by supplemental cooling and in that study colostrum quality was also improved by pre-partum cooling. Two studies were conducted to determine the effect of adding sprinklers to a system that already included shade and fans and also to determine the impact of timing of sprinkler use. These studies used mid lactation cows and heifers. Adding sprinklers to the system increased milk production 1 kg/d in second and later lactation animals but only increased milk production .6 kg/d in primiparous animals. A second study used humidistats to run sprinklers when relative humidity was less than 80%. This strategy decreased milk production and proved to be ineffective in Louisiana.

Impacts
Heat stress is very detrimental to dairy production and efficiency in the South. Management and nutritional strategies to alleviate heat stress are needed in order to allow the dairy producers in the South to compete efficiently in the market. The results of this research show that there are strategies that can improve performance during hot humid weather in Louisiana.

Publications

  • Ward, J.D., T.R. Smith, L. Zeringue, R.J. Williams, J. Crouch, R. Walz, T. Nueefch, and H.M. Wilson. 2004. The effects of feeding yeast culture during the transition from cool to hot weather to Holstein cows on animal performance. J. Dairy Sci. 87(suppl. 1):303.
  • Ward, J.D., 2003. The effect of short vs long term yeast supplementation during the transition period of Holstein cows. J. Dairy Sci. 86(Suppl. 1):218.
  • Ward, J. 2003. Managing Heat Stress in Lactating Cows in South Louisiana and Mississippi. Southeast Research Station Field Day Summaries. LSU AgCenter, Baton Rouge. Research Summary #153.


Progress 01/01/03 to 12/31/03

Outputs
Three trials were completed on this project during the summer of 2003. All three trials used component fed Holstein cows. Grain was offered twice a day before each milking and the amount offered was determined by milk production. A mixture of forage, soybean meal, and whole cottonseed was offered ad libitum. Orts were removed and fresh feed offered twice a per day. The first study investigated the effects of yeast culture and a dietary fiber digestion enzyme on the performance of mid to late lactation dairy cattle during the transition from cool to hot weather. Neither dietary treatment had any effect on milk production, feed intake, or body condition score change. The second trial investigated the effects of prepartum cooling on subsequent cow performance. Prepartum cooling had no effect on milk production but appeared to decrease postpartum dry matter intake. However, in this study cooling had no effect on body temperature so more research is needed to determine effective cooling strategies for prepartum cows. The third trial investigated the use of water in addition to fans and shade to cool mid to late lactation Holstein cows. Both groups of cows were housed in the same free stall barn with identical feeding facilities, free stalls and fans on each side. One half were cooled using water nozzles (5.75 l/min) set to be on for 2 minutes and off for 13 minutes during each 15 minute cycle. Sprinklers were allowed to cycle continuously from 7 a.m. until 7 p.m. The additional cooling provided by the water increased milk production (27.8 vs 26.9 kg) in both cows and heifers but the difference was greater in second and later lactations (30.0 vs 29.0 kg) than in heifers (25.6 vs 25.0 kg). Sprinklers decreased body temperatures at the p.m. sample time (39.1 vs 39.4 degrees C), but actually increased them at the am sample time (38.8 vs 38.7 degrees C).

Impacts
Heat stress is very detrimental to dairy production and efficiency in the South. Management and nutritional strategies to alleviate heat stress are needed in order to allow the dairy producers in the South to compete efficiently in the market. The results of this research show that there are strategies that can improve performance during hot humid weather in Louisiana.

Publications

  • Ward, J. D., 2003. The effect of short vs long term yeast supplementation during the transition period of Holstein cows. J. Dairy Sci. 86(suppl. 1):218.
  • Ward, J. 2003 Managing Heat Stress in Lactating Cows in South Louisiana and Mississippi. Southeast Research Station Field Day Summaries. LSU AgCenter, Baton Rouge. Research Summary #153.


Progress 01/01/02 to 12/31/02

Outputs
A 56 d study using 30 Holsteins was conducted to determine the effect of yeast culture supplementation during the transition period. Treatments were control, yeast supplementation from 21 d prior to expected calving date through 21 d after calving (short regimen) and yeast supplementation 21 d prior to expected calving date through 56 d after calving (long regimen). Prior to calving, cows received 3.6 kg of DM per d of a concentrate mix, ad libitum access to bermudagrass hay and pasture, and 3.8 kg of DM of corn silage every other d. After parturition, multiparous cows and primiparous cows received 8.1 or 7.3 kg of DM per d, respectively, of a concentrate mix. All cows received, for ad libitum consumption, a mixture containing on a DM basis 13.0% alfalfa hay, 15.9% whole cottonseed, 63.47% corn silage, and 7.6% soybean meal. Yeast culture was added (56.7 g prior to and 113.4 g after calving) to the concentrate of treatment cows. Plasma was collected on d 7, 14, 21, 28, and 56 for BHBA analysis. Milk components were analyzed every 14 d. Milk production, BHBA on d 7, 14, 21, and 28 d, DMI, and milk component data were analyzed using the mixed models of SAS and differences among treatments were tested using single degree of freedom contrasts. General linear models of SAS were used to analyze BHBA concentrations on d 56 and differences among treatments were analyzed using single degree of freedom contrasts. The contrasts were yeast supplementation vs no supplementation, and length of yeast supplementation. Overall, yeast supplementation had no effect on DMI, or milk production. However, cows on the long regimen had greater (P = 0.02) milk production (36.2 vs 33.7 kg per d) and less (P = 0.06) grain intake (7.3 vs 7.4 kg of DM per d) than cows on the short regimen. Neither yeast supplementation nor length of supplementation had any effect on BHBA during the first 28 d of the study. However, on d 56 cows on the long regimen had lower (P = 0.06) plasma BHBA concentration than cows on the short regimen (5.11 vs 7.4 mg/dL). Neither yeast supplementation nor length of yeast supplementation had any effect on SCC or milk fat. However, yeast supplementation decreased (P = 0.09) milk protein content (2.67 vs 2.81%). In this study yeast supplementation was only beneficial when fed throughout the entire study.

Impacts
Yeast culture supplementation can improve performance of dairy cattle calving during the summer weather. The improvement in milk production occurs during the late summer and early fall which is typically the time when our producers receive the highest price for their milk. This should lead to increased profitability of dairy producers in Louisiana.

Publications

  • Ward, J. D. 2002 .The effects of supplementing yeast culture during the transition period on performance of Holstein cows during hot humid weather. J. Dairy Sci. 85 (Suppl. 1):119


Progress 01/01/01 to 12/31/01

Outputs
A trial using 40 early lactation cows was conducted to determine the effect of dietary DCAD on dry matter intake and milk production during the first 8 wk of lactation. Cows were assigned to dietary treatment at parturition and immediately given experimental rations. Cows were component fed with the grain portion of the diet being offered separately. Only the grain portion of the diet differed. The grain supplements fed were control (DCAD 20.9 meq/100 g, Nel .39 Mcal/kg), DCAD (67.2 meq/ 100 g, Nel .37 Mcal/kg ) DCAD + fat, (DCAD 67.2 meq/100 g, Nel .39 Mcal/kg), and fat (DCAD 20.9 meq/100 g, Nel .40 Mcal/kg).Cows were given 4.1 kg of experimental grain mixes twice per day. They were given ad libitum access to a partial mixed ration (PMR) consisting of 16% alfalfa hay, 16% whole cottonseed, 54% corn silage, and 13% ryegrass haylage. Feeding the increased DCAD grains decreased (P < 0.01) grain intake. However, these groups consumed more (P < 0.07) PMR. Total dry matter consumption was approximately 19.9 kg / d for each treatment and was unaffected by dietary treatment. Milk production was also unaffected by dietary treatment and avg 34.8 kg / d. Peak milk production was similar across dietary treatments and averaged 45.8 kg. Days to peak milk was similar across treatments and averaged 43.8 d. In addition neither loss of body condition nor plasma beta-hydroxy butyrate were affected by dietary treatment.

Impacts
Previously increased dietary cation-anion difference has been shown to increase performance of heat stressed dairy cattle fed total mixed rations. This study suggests that the effects of dietary cation-anion difference may not occur when cattle are component fed.

Publications

  • No publications reported this period