Progress 10/01/02 to 09/30/07
Outputs
We completed four experiments to assist us in our continued development of reproductive management tools to enhance pregnancy rates in artificial insemination protocols and enhance overall reproductive efficiency. Three studies were conducted to evaluate the us of human chorionic gonadotropin (hCG) in estrous synchronization protocols. As a tool for ovulating follicles in noncycling cows, we previously established that hCG is more effective than GnRH products. Therefore, we have been evaluating the potential for replacing GnRH with hCG in these protocols. We established that heifers injected with 1,000 IU of hCG or 100 ug of GnRH had similar response in terms of corpus luteum regression and follicular growth when the PGF was administered on d 5 or 7 after treatment. However, there were differences in ovulation, and estrus detection responses to heifers receiving PGF at 5 or 7 days after hCG or GnRH treatment. Treatment of hCG prior to estrous synchronization with the
CO-Synch + CIDR protocol may enhance fertility, but not if hCG replaces GnRH at TAI. A novel forth study was completed with objectives to evaluate differences in calving distribution within individual herds of cattle that were inseminated after a fixed-time AI (TAI) compared to cows naturally mated. Five hundred and forty eight cows from five herds were stratified by days postpartum and body condition score before being randomly assigned to one of two treatments: 1) on d 1 cows were exposed to a bull for natural mating throughout the breeding season (Bull bred; n = 283); and 2) cows were treated with the CO-Synch + CIDR protocol with the TAI occurring on d 0, with cows being exposed to clean-up bulls on d 1. All cows in both treatments were managed as a single herd. All management continued within each herd as per the normal operating procedures for those herds. Of the 357 calve from which sex was determined 171 were the result of cows being exposed to TAI and 186 were in the Bull
bred treatment. There was no location x calf sex interaction and overall 49% of all calves were female. In addition, calf birth weight was not affected by treatment, but was affected by location, although there was no location x treatment interaction. Overall calf birth weight was 34.4 kg. Calving distribution was affected by treatment and location, with no interaction. We concluded that calving distribution of suckled beef cows receiving a TAI followed by natural service was altered compared to cows exposed only to natural service. Average calving date favored those cows exposed to TAI.
Impacts
Developing methods to enhance response of follicles to fixed-time AI protocols is critical to enhancing overall pregnancy rates to those protocols. Therefore, the potential for the use of hCG in heifer estrous synchronization protocols could enhance fertility to heifers exposed to fixed-time AI and result in a greater proportion of AI sired calves. In addition, improvement in fertility will generate more interest by beef producers to utilize fixed-time AI estrous synchronization systems, thus enhancing the overall use of AI. Methods of concentrating the calving season and developing more uniform calf crops enhance the income generated for calves and also increase marketing opportunities of those calves. Therefore, altering the calving season through estrous synchronization of cow herds has the potential to impact numerous beef producers.
Publications
- Lamb, G.C., D.R. Brown, J.E. Larson, C.R. Dahlen, N. DiLorenzo, J.D. Arthington, and A. DiCostanzo. 2007. Effect of organic or inorganic trace mineral supplementation on follicular response, ovulation, and embryo production in superovulated angus heifers. Anim. Reprod. Sci. (In press: ANIREP3354)
- Lamb, G.C., J.E. Larson, T.W. Geary, J.S. Stevenson, S.K. Johnson, M.L. Day, R. P. Ansotegui, D. J. Kesler, J.M. DeJarnette, and D. Landblom. 2006. Synchronization of estrus and artificial insemination in replacement beef heifers using GnRH, PGF2α and progesterone. J. Anim. Sci. 84:3000-3009.
- Lamb, G.C. 2007. Current advances in assisted reproductive technologies. Proc. 2007 Wild West Veterinary Conference Proceedings, Reno, NV (In press).
- Lamb, G.C. 2007. Recommended estrus synchronization protocols and reproductive management of beef cows. Proc. 2007 Wild West Veterinary Conference Proceedings, Reno, NV (In press).
- Lamb, G.C. 2007. Estrus synchronization protocols for cows. 8th Applied Reproductive Strategies in Beef Cattle, Billings, MT (In press).
- Lamb, G.C. 2007. Factors affecting pregnancy rates in an embryo transfer program. In: Proc. XI Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. pp 128-134.
- Lamb, G.C. 2007. Resynchronization of estrus using a progestin. In: Proc. XI Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. pp 162-171.
- Lamb, G.C., J.E. Larson, and C.R. Dahlen. 2007. Fixed-time AI in beef cows and heifers with a CIDR plus GnRH and/or hCG. In: Proc. XI Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 144-153.
- Lamb, G.C., and L. Schott. 2007. Targeting a branded beef program. 2007 MN Cow/Calf Day Report pp 1-5.
- Burns, M.G., B.S. Buttrey, D.R. Eborn, J.E. Larson, B.J. Lovaas, G.C. Lamb, K.C. Olson, J.S. Stevenson. 2007. Evaluation of human chorionic gonadotropin (hCG) as a replacement for GnRH in an ovulation- synchronization protocol before fixed timed AI. J. Anim. Sci. 85 (Suppl. 1):320.
- Dahlen, C.R., J.E. Larson, G. Marquezini, G.C. Lamb. 2007. Effects of human chorionic gonadotropin (hCG) and gonadotropin releasing hormone (GnRH) on follicle and corpus luteum dynamics and concentrations of progesterone in pre-pubertal Angus heifers. J. Anim. Sci. 85 (Suppl. 1):648.
- Lamb, G.C., J.E. Larson, C.R. Dahlen, G. Marquezini. 2007. Fixed-time artificial insemination in replacement beef heifers after treatment with human chorionic gonadotropin (hCG), progesterone, and prostaglandin F2α. J. Anim. Sci. 85 (Suppl. 1):321.
- Lamb, G.C., B.J. Lovaas, S.L. Bird, A. Martins, J.E. Larson, J.C. Rodgers, D.J. Frank, and D.M. Williams. 2007. Artificial insemination of superovulated Angus cows using sexed or conventionally frozen semen. J. Anim. Sci. 85 (Suppl. 1):322.
- Lamb, G.C., C.R. Dahlen, K. A. Vonnehamme, G. R. Hansen, J. D. Arseneau, G. A. Perry, R.S. Walker, J. Clement, and J. D. Arthington. 2007. Influence of a CIDR prior to bull-breeding on pregnancy rates and subsequent calving distribution. Anim. Reprod. Sci. (In press: ANIREP-D-07-988).
- Wheaton, J.E. and G.C. Lamb. 2007. Induction of cyclicity in postpartum anestrous beef cows using progesterone, GnRH and estradiol cypionate (ECP). Anim. Reprod. Sci. Nov. 19 [EPub ahead of print - ANIREP-D-06-586].
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Progress 01/01/06 to 12/31/06
Outputs
Experiment 1. We determined the effect of administering 1,000 IU or 500 IU hCG on subsequent ovarian structure dynamics and concentrations of progesterone in purebred Angus heifers. Heifers (n = 47) were stratified by age and weight and randomly assigned to one of three treatments: 1) heifers received a 100 g injection of GnRH (n = 16); 2) heifers received 1000 IU hCG (n = 16); and 3) heifers received 500 IU hCG (n = 15). The ovaries of each heifer were examined daily and mapped by transrectal ultrasonography to monitor ovarian structure dynamics beginning one day before treatment was administered and continuing until day nine after treatment. In addition, blood samples were collected daily starting the day before treatment until day nine after treatment. Concentrations of progesterone in serum were determined by RIA. We determined that injection of 500 or 1,000 IU of hCG was more effective at ovulating follicles and inducing a new corpus luteum than GnRH in
noncycling replacement beef heifers. However, use of 1,000 IU of hCG to replace GnRH in the CO-Synch + CIDR protocol resulted on poorer fertility. Experiment 2. We determined the effect of administering hCG 14 d prior to initiation of the Co-Synch protocol and whether replacing GnRH with hCG at CIDR insertion would enhance pregnancy rates in the CO-Synch protocol. Using a 2 x 2 factorial design of treatments five hundred forty seven replacement beef heifers were assigned to one of four treatments: 1) heifers received a 100 ug injection of GnRH at CIDR insertion (d -7) and a 25 mg injection of PGF at CIDR removal (d 0), followed in 54 hr by a fixed-time AI (TAI) with a second injection of GnRH (Control GnRH; CG; n = 160); 2) CG but the first injection of GnRH was replaced with a 1,000 IU of human chorionic gonadotropin (hCG; CH; n = 158); 3) CG, plus heifers received a 1,000 IU injection of hCG 14 d prior to CIDR insertion (HG; n = 116); and 4) CH, plus heifers received a 1,000 IU
injection of hCG 14 d prior to CIDR insertion (HH; n = 113). Blood samples were collected on d -31, -21, -14, -7, 0, 2 to harvest serum for later analysis of concentrations of progesterone. Progesterone was used to determine cycling status and response to estrous synchronization. Pregnancy was diagnosed by transrectal ultrasonography on d 33 after TAI. Overall there was a difference in pregnancy rates among heifers originating from four separate locations with a range from 16 to 40%. Cycling prior to initiation of treatments did not affect overall pregnancy rates and heifers receiving a 1,000 IU injection of hCG 14 d prior to initiation of estrous synchronization did not have an increase in pregnancy rates. However, substituting GnRH with a 1,000 IU injection of hCG at CIDR insertion resulted in reduced pregnancy rates. Overall there were no statistical differences among the four treatments (37, 30, 46, and 28 % for CG, CH, HG, and HH treatments, respectively). We conclude that
replacement of the first injection of GnRH of the CO-Synch + CIDR protocol with a 1,000 IU injection of hCG appear to result in reduced pregnancy rates and is not a suitable alternative to GnRH.
Impacts
Reports have indicated that the use of artificial insemination in the beef industry remains between low (between 5 and 8% of producers) because of factors such as labor, time, and convenience. We have developed two short (less than 10 days) estrous synchronization systems that can be utilized by producers with exceptional pregnancy rates. One of those systems (CO-Synch+CIDR) is a fixed-time AI system that requires no detection of estrus, thus providing a protocol that reduces time associated with detection of estrus in beef herds. Developing methods to enhance response of follicles to fixed-time AI protocols is critical to enhancing overall pregnancy rates to those protocols. Therefore, the potential for the use of hCG in heifer estrous synchronization protocols could enhance fertility to heifers exposed to fixed-time AI and result in a greater proportion of AI sired calves. In addition, improvement in fertility will generate more interest by beef producers to utilize
fixed-time AI estrous synchronization systems, thus enhancing the overall use of AI. Methods of concentrating the calving season and developing more uniform calf crops enhance the income generated for calves and also increase marketing opportunities of those calves. Therefore, altering the calving season through estrous synchronization of bull breeding herds has the potential to impact 90% of beef producers that do not utilize AI to alter their calving distribution.
Publications
- Lamb, G.C. J.E. Larson, and C.R. Dahlen. 2006. Review of Estrous Synchronization Systems:CIDR. 6th Applied Reproductive Strategies in Beef Cattle, St. Joseph, MO pp 105-120.
- Lamb, G.C. 2006. Review of Current Estrous Synchronization Protocols for Beef Cattle. Pfizer Veterinary Technical Conference, Galena, IL (03/12/2006).
- Lamb, G.C. 2006. Strategies to improve pregnancy rates in beef recipients. American Association of Bovine Practitioners Pre-Conference Seminar, St. Paul, MN (09/20/2006).
- Lamb, G.C. 2006. Nutritional management of donors and recipients. American Association of Bovine Practitioners Pre-Conference Seminar, St. Paul, MN (09/20/2006).
- Lamb, G.C. 2006. Up-date on the use of sexed semen. American Association of Bovine Practitioners Pre-Conference Seminar, St. Paul, MN (09/20/2006).
- Lamb, G.C. 2006. Physiological principles and hormonal control of the estrous cycle. American Association of Bovine Practitioners Pre-Conference Seminar, St. Paul, MN (09/20/2006).
- Carriquiry, M., W. J. Weber, C. R. Dahlen, G. C. Lamb, S. R. Sanders, L. H. Baumgard, B. A. Crooker. 2006. Bovine somatotropin and dietary fat enriched with omega-3 fatty acids in dairy cows: II. Milk fatty acid composition. J. Anim. Sci. J. Anim. Sci. 84 (Suppl. 1):63.
- Carriquiry, M., C. R. Dahlen, W. J Weber, G. C. Lamb, B. A. Crooker. 2006. Bovine somatotropin and dietary fat enriched with omega-3 fatty acids in dairy cows: III. Postpartum ovarian activity. J. Anim. Sci. 84 (Suppl. 1):346.
- Cooke, R. F., J. D. Arthington, C. R. Staples, W. W. Thatcher, and G. C. Lamb. 2006. Effects of supplement type on performance, reproductive, and physiological responses of Brahman-crossbred females. J. Anim. Sci. (Submitted). Galindo-Gonzalez, S., J.D. Arthington, J.V. Yelich, G.R. Hansen, G.C. Lamb, A. DeVries. 2006. Effects of Cow Parity on Voluntary Hay Intake and Performance Responses to Early Calf Weaning. Livestock Sci. (In Press).
- Lamb, G.C., D.R. Brown, J.E. Larson, C.R. Dahlen, N. DiLorenzo, J.D. Arthington, and A. DiCostanzo. 2006. Effect of Organic or Inorganic Trace Mineral Supplementation on Follicular Response, Ovulation, and Embryo Production in Superovulated Angus Heifers. Anim. Reprod. Sci. (Submitted).
- Lamb, G.C., J.E. Larson, T.W. Geary, J.S. Stevenson, S.K. Johnson, M.L. Day, R. P. Ansotegui, D. J. Kesler, J.M. DeJarnette, and D. Landblom. 2004. Synchronization of estrus and artificial insemination in replacement beef heifers using GnRH, PGF2 and progesterone. J. Anim. Sci. (In press).
- Larson, J. E., G. C. Lamb, J. S. Stevenson, S. K. Johnson, M. L. Day, T. W. Geary, D. J. Kesler, J. M. DeJarnette, F. N. Schrick, A. DiCostanzo, and J. D. Arseneau. 2006. Synchronization of estrus in suckled beef cows for detected estrus and artificial insemination and timed artificial insemination using gonadotropin-releasing hormone, prostaglandin F2alpha, and progesterone. J Anim Sci. 2006 Feb;84(2):332-342.
- Santos, N.R., G.C. Lamb, H.B. Roman, R.O. Gilbert. 2006. Postpartum endometrial cytology in beef cows. Theriogenology (Accepted).
- Wheaton, J.E. and G.C. Lamb. 2006. Induction of cyclicity in postpartum anestrous beef cows using progesterone, GnRH and estradiol cypionate (ECP). Anim. Reprod. Sci. (In Press).
- Carriquiry, M., W. J. Weber, C. R. Dahlen, G. C. Lamb, B. A. Crooker. 2006. Bovine somatotropin and dietary fat enriched with omega-3 fatty acids in dairy cows: I. Lactation performance. J. Anim. Sci. 84 (Suppl. 1):63.
- Cooke, R. F., C. R. Staples, G. C. Lamb, and J. D. Arthington. 2006. Effects of supplement type on performance, reproductive and physiological parameters of yearling Brahman-crossbred heifers. J. Anim. Sci. 84(Suppl. 2):8.
- Lamb, G. C., C.R. Dahlen, K. A. Vonnahme, G. R. Hansen, J. D. Arseneau, G. A. Perry, J. Clement, J. D. Arthington. 2006. Effects of estrous synchronization with a CIDR prior to the breeding in bull-breeding herds on pregnancy rates. J. Anim. Sci. 84 (Suppl. 1):433.
- Thielen, K. N. J. E. Larson, B. J. Lovaas, D. J. Kesler, J. S. Stevenson, T. T. Marston, and G. C. Lamb. 2006. Influence of a CIDR insert after a fixed-time AI on pregnancy rates and return to estrus of nonpregnant cows. J. Anim. Sci. 84 (Suppl. 1):432.
- Lamb, G.C. 2006. Donor and Recipient Factors Affecting and Embryo Transfer Program. 7th Applied Reproductive Strategies in Beef Cattle, Rapid City, SD pp 269-280.
- Lamb, G.C. 2006. Nutritional factors affecting reproduction in young beef cows. 2006 Tennessee Nutrition Conference Proceedings 22-33.
- Lamb, G.C., and A. DiCostanzo. 2006. Current and future trends of market cattle. 2006 MN Cow/Calf Day Report 6-14.
- Lamb, G.C. J.E. Larson, and C.R. Dahlen. 2006. Review of Estrous Synchronization Systems:CIDR. 7th Applied Reproductive Strategies in Beef Cattle, Rapids City, SD pp 103-116.
- Lamb, G.C. 2006. Control of estrous cycle using CIDR and GnRH. American Association of Bovine Practitioners Pre-Conference Seminar, St. Paul, MN (09/20/2006).
- Lamb, G.C. 2006. Nutritional considerations for successful implementation. American Association of Bovine Practitioners Pre-Conference Seminar, St. Paul, MN (09/20/2006).
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Progress 01/01/05 to 12/31/05
Outputs
Exp. 1. The influence of a CIDR after fixed-time AI on pregnancy rates and return to estrus of non-pregnant cows. First service TAI pregnancy rates were similar among treatments and overall pregnancy rates after second service also were similar among treatments. Cows in the CIDR5-21 and CIDR14-21 more effectively resynchronized the return estrus of cows that failed to become pregnant to the TAI. The distribution of estrus for those two treatments was ensured that a greater portion of cows would be inseminated within the desirable 3-day window following CIDR removal. Our results indicate that that insertion of a CIDR between 5 and 21 d or 14 and 21 days after TAI enhances the percentage of cows that express estrus during a shorter duration. However, conception rates to the return estrus appears to be compromised compared to Controls. Exp. 2. The influence of a CIDR prior to bull-breeding on pregnancy rates and subsequent calving distribution. Overall pregnancy rates
within the first 30 days of the breeding season were similar between CIDR (64.4%) and Control (64.7%). The CIDR treatment did not appear to alter overall pregnancy rates, which were 89.7% for CIDR cows and 89.6% for Control cows. The average date of pregnancy significantly favored cows receiving a CIDR (20.1 +/- 0.8 d) compared to Controls (23.2 +/- 0.8 d). However, a similar percentage of cows became pregnant within the first 21 days of the breeding season for both treatments (Figure 2). Body condition score, parity, and days postpartum also did not alter the average number of days before cows became pregnant. Exp. 3. The effectiveness of progesterone, GnRH, and estradiol cypionate to induce estrous in noncycling cows. Cows were assigned sequentially by calving date to four treatment groups: 1) PGF2 , 2) CIDR-PGF2, 3) GnRH-CIDR-PGF2, and 4) ECP-CIDR-PGF2. Intravaginal CIDR inserts were in place from d -7 to 0. Single injections of GnRH and ECP were administered on d -7, and PGF2 was
administered on d 0. Day 0 averaged 38 d postpartum. Incidence of treatment-induced cyclicity was influenced by treatment and parity. Percentages of cyclic cows were greater in the three CIDR-treated groups (P = 0.002) than in the PGF2 group (53 and 0%, respectively). Principle Accomplishments. 1 - Insertion of a CIDR between 5 and 21 days after TAI does not appear to enhance or reduce pregnancy rates in suckled beef cows. However, a CIDR from 14 to 21 days after TAI reduces fertility to the AI at the subsequent estrus. 2 - Utilization of a CIDR prior to initiation of the breeding season does not enhance overall pregnancy rates, but does alter the average fetal age and the percentage of females pregnant within the first 10 days of the breeding season. 3 - Treatment of beef cows with CIDR at about 40-d postpartum provides an approach to reduce the herd calving interval, gain a more uniform calf-crop, and to breed more cows earlier during the following breeding season. Additional
treatment with GnRH or ECP does not appear to improve the ovulatory response over that of CIDR alone.
Impacts
Synchronization of the estrous cycle has the potential to shorten the calving season, increase calf uniformity, and enhance the possibilities for utilizing AI. Artificial insemination allows producers the opportunity to infuse superior genetics into their operations at costs far below the cost of purchasing a herd sire of similar standards. These tools remain the most important and widely applicable reproductive biotechnologies available for beef cattle operations. The development of reliable estrous synchronization protocols for TAI in beef cows and heifers has the potential to alter reproductive performance in numerous herds. Estrous synchronization can be an effective means of increasing the proportion of females that become pregnant early in the breeding season resulting in shorter calving seasons and more uniform calf crops. Effective estrous synchronization programs offer the following advantages: 1) cows or heifers are in estrus at a predicted time which
facilitates AI; 2) the time required for detection of estrus is reduced thus decreasing labor expense associated with detection of estrus; and 3) cycling females will conceive earlier during the breeding period. Only 8.1% of beef cattle operations in the U.S. use these management procedures on replacement beef heifers or postpartum beef cows to improve reproductive management of their herds and ultimately improve profitability.
Publications
- Fricke, P.M. and G.C. Lamb. 2005. Potential Applications and Pitfalls of Reproductive Ultrasonography in Bovine Practice. In: Veterinary Clinics of North America: Food Animal Practice pp 419-436. Elsevier Inc. Philadelphia, PA.
- Lamb, G.C., J.A. Cartmill, and J.S. Stevenson. 2004. Effectiveness of Select Synch (Gonadotropin-releasing hormone and prostaglandin F2[alpha]) for synchronizing estrus in replacement beef heifers. Prof. Anim. Sci. 20:27-33.
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Progress 01/01/04 to 12/31/04
Outputs
1) Influence of a CIDR after fixed-time AI on pregnancy rates and return to estrus of non-pregnant cows. Beef cows from two locations (IL and MN) were estrous synchronized with the CO-Synch+CIDR protocol. At 60 hr after PGF all cows are inseminated at a fixed-time AI (TAI) and receive a second injection of GnRH. After the initial TAI cows were assigned to one of four resynchronization protocols. First service TAI pregnancy rates were similar among treatments and overall pregnancy rates after second service also were similar among treatments. Although pregnancy rates to first service were similar between locations (56.4 and 56.8% for IL and MN, respectively, the MN location (86.3%) had greater (P < 0.001) second service pregnancy rates than the IL location (59.8%). The difference in pregnancy rate could be partially attributed to an increase in embryonic loss between Day 32 and 62 of the study from the TAI pregnancy at the IL location compared to that at the MN
location. The results of this study indicate that insertion of a CIDR between 5 and 21 days after TAI does not appear to enhance or reduce pregnancy rates in suckled beef cows. However, insertion of a CIDR to resynchronize estrus appears to increase the percentage of nonpregnant cows that exhibit estrus in a more desirable 3-day window. 2) Induction of ovulation in early postpartum anestrous beef cows using CIDR, PGF and GnRH or ECP. Mature, suckled Angus cows were allotted by calving date to four blocks spaced 21-d apart. Dams were assigned sequentially by calving date to four treatments: 1) Cows received an injection of PGF on day 0; 2) cows received a CIDR insert, plus an injection of PGF; 3) cows received a CIDR and an an injection of GnRH, plus an injection of PGF; and 4) cows received a CIDR and an a 2mg injection of ECP, plus an injection of PGF. The number of cows forming a fully functional CL in treatment groups 1 to 4 were 3/26 (11.5%), 16/29 (55.2%), 15/24 (62.5%) and 15/27
(55.6%), respectively. Group 1 differed from groups 2, 3 and 4. Responses in groups 2, 3 and 4 were similar. A greater proportion of first-calf heifers (24/38, 63.2%) than mature cows (25/68, 36.8%) formed fully functional CL. Results demonstrated that treatment of early postpartum anestrous cows with CIDR induced ovulation and subsequent formation of a fully functional CL in 46% of the cows. 3) Synchronization of estrus in suckled beef cows and heifers using gonadotropin releasing hormone (GnRH) prostaglandin F2a (PG), and progesterone (CIDR). We determined whether a fixed-time artificial insemination (TAI) protocol could yield similar pregnancy rates to a protocol requiring detection of estrus and whether adding a CIDR to GnRH + PG-based protocols would enhance fertility. Estrus in 2,596 suckled beef cows from 14 locations and 2,077 heifers at 12 locations was synchronized using various estrus detection and TAI protocols using GnRH and/or CIDRs. Overall, the Hybrid Synch+CIDR
protocol consistently achieved the greatest pregnancy rates among locations; however, CO-Synch+CIDR was a reliable TAI protocol that gives producers the option to eliminate detection of estrus when inseminating beef cows or heifers.
Impacts
Reports have indicated that the use of artificial insemination in the beef industry remains between low (between 5 and 8% of producers) because of factors such as labor, time, and convenience. We have developed two short (less than 10 days) estrous synchronization systems that can be utilized by producers with exceptional pregnancy rates. One of those systems (CO-Synch+CIDR) is a fixed-time AI system that requires no detection of estrus, thus providing a protocol that reduces time associated with detection of estrus in beef herds. Synchronization of the return estrus in non-pregnant cows has application in herds that utilize a second AI. Concentrating the percentage of non-pregnant cows returning to estrus within a short window reduce the time associated with daily estrus detection. Therefore, we have demonstrated that cows can be effectively resynchronized with a CIDR and inseminated within a short window of time after CIDR removal.
Publications
- Lamb, G.C. 2004. Estrus synchronization systems CIDR. In: Proc. Applied Reproductive Strategies in Beef Cattle. Northe Platte NE. Pp 75-85.
- Lamb, G.C. 2004. Beef estrous synchronization systems. In: Proc. NAAB 58th Technical Conference (In press).
- Lamb, G.C. 2004. Synchronization of estrus in embryo transfer recipients using CIDRs and GnRH. In: Proc. AETA Annual Conference (In press).
- Lamb, G.C. 2004. Factors influencing reproductive efficiency in beef herds. In: Proc. VIII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 161-173.
- Lamb, G.C. 2004. Estrous synchronization using the CIDR and GnRH. In: Proc. VIII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 215-224.
- Lamb, G.C. 2004. Donor and recipient factors affecting embryo transfer programs. In: Proc. VIII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 247-255.
- Lamb, G.C. and P.M. Fricke. 2004. Ultrasound, Early Pregnancy Diagnosis and Fetal Sexing. In: Proc. Applied Reproductive Strategies in Beef Cattle. Northe Platte NE. Pp 219-229.
- Larson, J.E., G.C. Lamb, T.W. Geary, J.S. Stevenson, S.K. Johnson, M.L. Day, D. J. Kesler, J.M. DeJarnette, and D. Landblom. 2004. Synchronization of estrus in replacement beef heifers using GnRH, prostaglandin F2a (PG), and progesterone (CIDR): a multi-location study. J. Anim. Sci. 82 (Suppl. 1):368.
- Larson, J.E., G.C. Lamb, J.S. Stevenson, S.K. Johnson, M.L. Day, T.W. Geary, D. J. Kesler, J.M. DeJarnette, F.N. Schrick, and J.D. Arseneau. 2004. Synchronization of estrus in suckled beef cows using GnRH, prostaglandin F2a (PG), and progesterone (CIDR): a multi-location study. J. Anim. Sci. 82 (Suppl. 1):369.
- Wasson, R., J.E. Larson, D.R. Brown, A. DiCostanzo, J.D. Arthington, and G.C. Lamb. 2004. Cow and calf performance in a management system including twinning and early weaning. J. Anim. Sci. 82 (Suppl. 1):59.
- Dahlen, C.R., C.M. Zehnder, K.A. Hachmeister, M.E. Dikeman, A. DiCostanzo, G.C. Lamb, L.R. Miller, and H. Chester-Jones. 2004. Effects of Including Malting Industry Byproducts in Feedlot Diets on Performance and Beef Quality. Prof. Anim. Sci. Accepted (# 04-282).
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Progress 01/01/03 to 12/31/03
Outputs
Six Angus cows at the North Central Research and Outreach Center, Grand Rapids, MN, were diagnosed pregnant with twins (TWIN) via transrectal ultrasonography after receiving one embryo, 7 days following TAI. Following delivery of two live calves TWIN cows were matched with cows delivering single calves, assigned to be weaned early (75 days, SE and TWIN) or late (205 days, SL). Cows delivering and raising twin calves tend to calve at a lower BCS than those with singles, which may have an impact on milk production later in lactation. However, cows with twins show a significant increase in total kilograms of calf produced per cow, resulting in higher productivity/cow. Early weaning may prove beneficial in maintaining BCS of twinning cows and contribute to an earlier return to estrous. In experiment two, our objectives were to determine whether a fixed-time AI (TAI) protocol could yield similar pregnancy rates to a protocol requiring detection of estrus and whether
inclusion of a CIDR to GnRH + prostaglandin F2a (PG) based protocols would enhance fertility. Postpartum suckled beef cows were assigned randomly to each of five estrus-synchronization protocols using GnRH, PG and(or) a CIDR. Protocols were Control, CO-Synch, CO-Synch + CIDR, Hybrid-Synch, and Hybrid Synch + CIDR. The percentage of cows cycling at the initiation of estrus synchronization was 66.8% and the percentage of cycling cows ranged from 38 and 90% among locations. Overall pregnancy among locations ranged from 39% to 67%. Overall the Hybrid Synch + CIDR protocol most consistently achieved the greatest pregnancy rates; however, CO-Synch + CIDR is a reliable timed AI protocol that gives producers the option to eliminate detection of estrus when AI-breeding their cows. In experiment three, our objectives were to determine whether a TAI protocol could yield similar fertility rates to a protocol requiring detection of estrus and whether an injection of GnRH at CIDR insertion enhances
pregnancy rates. Replacement beef heifers from 12 locations were assigned randomly to each of four estrus-synchronization protocols using GnRH, PG, and(or) a CIDR insert. All heifers received a CIDR for 7 days with an injection of PG on the day of CIDR removal. For two treatments heifers were observed for estrus detection during 84 hr after PG followed by TAI and GnRH for any heifer not detected in estrus. The EAI heifers did not receive GnRH at CIDR insertion, whereas GnRH + EAI heifers received GnRH. For the two additional treatments all heifers were assigned to receive a single TAI at 60 hr after PG. Heifers in the TAI treatment did not receive GnRH at CIDR insertion, whereas heifers in the GnRH + CIDR treatment received GnRH at CIDR insertion. Although no differences in pregnancy rates among treatments were observed, the GnRH + EAI treatment most consistently achieved the greatest pregnancy rates. In addition, the GnRH + TAI protocol provides an alternative for producers to
synchronize heifers with TAI as an option without detection of estrus.
Impacts
There are approximately 16,000 beef producers in Minnesota representing 400,000 cows. By inducing twins in an operation, we could potentially increase the pounds weaned per cow by 100 pounds - resulting in an increase of an additional 400,000 pounds of beef to producers. In other words increase income to operations in total of $400,000.00. In addition, estrous synchronization improves uniformity, genetic potential and pregnancy rates. By increasing the percentage of cattle estrous synchronized from 7% to 20% will result in economic improvements to the MN producers in excess of $1million, considering that the improvement in production for cows estrous synchronized results in a minimum of $20/cow
Publications
- Dahlen, C.R, A. DiCostanzo, R.T. Ethington, T.L. Durham, J.E. Larson, and G.C. Lamb. 2003. Evaluation of forage sources for finishing diets containing wet corn gluten feed. J. Anim. Sci. 81(Suppl. 1):61.
- Dahlen C.R., G.C. Lamb, C.M. Zehnder, L.R. Miller, and A. DiCostanzo. 2003. Fixed-time insemination in peripuberal, light-weight replacement beef heifers synchronized with PGF2alpha and GnRH. Theriogenology 59(8):1827-1837.
- Dahlen, C.R., and G.C. Lamb. 2002. Feeding melengestrol acetate (MGA) to resynchronize repeat estrus in beef heifers previously synchronized using a MGA/prostaglandin F2a protocol. J. Anim. Sci. 80(Suppl. 2):56.
- Dahlen, C.R., G.C. Lamb, B. Lindsay, A. DiCostanzo, D.R. Brown, A.R. Spell, and L.R. Miller. 2002. Pregnancy rates in recipients after receiving either two-identical demi-embryos or a single whole embryo. Theriogenology 57:539.
- Fricke, P.M., and G.C. Lamb. 2002. Practical applications of ultrasound for reproductive management of beef and dairy cattle. In: Proc. Applied Reproductive Strategies in Beef Cattle Workshop. Manhattan, KS.
- Hafliger, III, H.C., L.H. Baumgard, W.J. Weber, M. Chahine, G.C. Lamb, T.H. Klusmeyer, M.F. McGrath, J.L. Vicini, and B.A. Crooker. 2003. Effects of induced lactation on milk fatty acid profiles in multiparous Holstein cows. J. Anim. Sci. 81(Suppl. 1):189.
- Lamb, G.C. 2002. GnRH estrus and ovulation control systems for beef cattle. In: Proc. Applied Reproductive Strategies in Beef Cattle Workshop. Manhattan, KS.
- Lamb, G.C., and C.R. Dahlen. 2002. Long-term effects of nutrition on reproduction - how can cattlemen manipulate their operations for optimum reproductive performance. 2002 MN Beef Cow/Calf Day Report pp. 44-58.
- Lamb, G.C., J.A. Cartmill, and J.S. Stevenson. 2003. Effectiveness of Select Synch (Gonadotropin-releasing hormone and prostaglandin F2[alpha]) for synchronizing estrus in replacement beef heifers. Prof. Anim. Sci. (In press).
- Miller, L.R., A. DiCostanzo, C.M. Zehnder, G.C. Lamb, and L. Smith. 2003. Effects of two protein supplementation systems on feedlot performance and nitrogen retention by feedlot steers. J. Anim. Sci. (Submitted:E2002-368).
- Lamb, G.C., C.R. Dahlen, and D.R. Brown. 2002. Reproductive Ultrasound Technology for Monitoring Ovarian Structure Development, Fetal Development, Embryo Survival, and the incidence of Twinning in Beef Cows. Prof. Anim. Sci. 19:135-143.
- Lamb, G.C., D.R. Brown, R.C. Wasson, J.E. Larson, C.R. Dahlen, and A. DiCostanzo. 2003. Effect of Trace Mineral Nutrition on Follicular Response, Ovulation, and Embryo Production in Superovulated Angus Heifers. J. Reprod. Fertil. (Submitted).
- Lamb, G.C., R.C. Wasson, D.R. Brown, and C.R. Dahlen. 2003. Induced twinning by artificial insemination and embryo transfer fails to increase pregnancy rates but increases total fetus numbers in beef cows. J. Anim. Sci. 81(Suppl. 1):178.
- Lamb, G.C., D.R. Brown, R. D. Mathison, J.B. Hall. 2002. Effect of pasture forage specie and management on animal performance. J. Agronomy (Suppl. 1).
- Lamb, G.C., D. R. Brown, C. R. Dahlen, and A. R. Spell. 2002. Inducing twinning in postpartum suckled beef cows using artificial insemination and embryo transfer. J. Anim. Sci. 80(Suppl. 1):268.
- Lamb, G.C., and C.R. Dahlen. 2002. Past, Present, and Future impact of ultrasound technology on beef cattle reproductive research and management strategies. J. Anim. Sci. 80(Suppl. 2):54.
- Lamb, G.C. 2003. Estrous synchronization using the newly approved CIDR. 2003 MN Beef Cow/Calf Day Report pp. 28-42.
- Lamb, G.C. 2003. Estrous synchronization in beef cattle using the CIDR. In: Proc. VII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 199-211.
- Lamb, G.C. 2003. Melengestrol acetate (MGA) for synchronizing beef females. In: Proc. VII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 239-247.
- Lamb, G.C. 2003. Nutrition/reproduction interactions affecting performance of beef cattle. In: Proc. VII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 139-151.
- Lamb, G.C. 2003. Reproductive ultrasound for management of beef cattle. In: Proc. VII Conference Focusing on Production and Reproduction of Cattle. Uberlandia, Brazil. Pp 183-193.
- Stevenson, J.S., S.K. Johnson, M.A. Medina-Britos, A.M. Richardson, and G.C. Lamb. 2003. Resynchronization of estrus in cattle of unknown pregnancy status using estrogen, progesterone, or both. J. Anim. Sci. 81:1681-1692.
- Stevenson, J.S., G.C. Lamb, S.K. Johnson, M.A. Medina-Britos, D.M. Grieger, K.R. Harmoney, J.A. Cartmill, S.Z. El-Zarkouny, C.R. Dahlen, and T.J. Marple. 2003. Supplemental norgestomet, progesterone, and MGA increases pregnancy rates in suckled beef cows after inseminations. J. Anim. Sci. 81:571-586.
- Wasson, R.C., J.E. Larson, D.R. Brown, and G.C. Lamb. 2003. Inclusion of a CIDR after initial artificial insemination concentrations of progesterone and corpus luteum volume in suckled beef cows. J. Anim. Sci. 81(Suppl. 1):53.
- Arthington, J.D., G.C. Lamb, and F.M. Pate. 2003. Effect of Supplement type on growth and pregnancy rate of yearling, Brahman-crossbred heifers. Prof. Anim. Sci. (In press).
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