+publisher:"Virginia Tech" +contributor:("Umberger, Steven H.")

Virginia Tech

1. Jabbar, Ghulam. Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes.

Degree: MS, Animal and Poultry Sciences, 1993, Virginia Tech

URL: http://hdl.handle.net/10919/43419

► Two commercially available progestogen products for cattle, melengestrol acetate (MGA) and norgestomet (SMB) , were evaluated for their ability to induce synchronized estrus in… (more)

▼ Two commercially available progestogen products for cattle, melengestrol acetate (MGA) and norgestomet (SMB) , were evaluated for their ability to induce synchronized estrus in anovulatory ewes. Seasonally anestrous ewes (n=232; determined by blood serum progesterone concentration) of mixed breeding were randomly assigned within broad age groups to one of seven treatments: 1) control (C); 2) MGA only (OMGA); 3) MGA + zeranol (RMGA); 4) MGA + PG-600 (PMGA; 400 IU pregnant mare's serum gonadotropin + 200 IU human chorionic gonadotropin in a 5 mL dose); 5) 5MB only (OSMB); 6) 5MB + zeranol (RSMB); and 7) 5MB + PG-600 (PSMB). Beginning 10 d before breeding, OMGA, RMGA, and PMGA ewes were fed .3 mg MGA/d provided through a mixture of shelled com and a commercially prepared pelleted supplement containing MGA. Concomitantly, OSMB, RSMB, and PSMB ewes were given a 3 mg norgestomet implant inserted subcutaneously on the back of the ear. Immediately preceding initiation of the MGA and 5MB treatments, RMGA and RSMB ewes were given a single i.m. injection of 2.5 mg zeranol. At the end of the 10-d treatment period, MGA feeding was discontinued and the norgestomet implants were removed. Concomitantly, PMGA and PSMB ewes were given a single i.m. injection of PG-600 (5 mL). All treatment groups were combined into one breeding group on May 4, 1992, with a ram to ewe ratio of 1: 17 for a 30-d breeding period. Mating to synchronized estrus was greater (P < .0001) for progestogentreated ewes. Within progestogen treatments, more (P < .000 1) 5MB ewes were marked within the first 5 d of breeding than MGA ewes. Overall, there were no treatment differences in estrus response for the 30-d breeding period. Blood serum samples collected during the first 14 d of breeding were analyzed for progesterone as an indicator of corpora lutea formation. Even though a large proportion of C ewes displayed luteal activity, only 12 % exhibited behavioral estrus within the first 17 d of breeding. Progestogen treated ewes exhibited a shorter mean interval (P < .0001) from ram introduction to lambing. Fertility and prolificacy were not different for C, MGA, or 5MB ewes. Of the two progestogen treatments used alone, lambing rate was 85 and 59 % (P < .03) for OMGA and OSMB ewes, respectively. Ewes plimed with zeranol before MGA or 5MB treatment exhibited similar levels of fertility and intervals from ram introduction to lambing compared with ewes receiving an injection of PG- 600 after progestogen treatment. These data indicate that progestogen products commercially available for cattle may be useful in enhancing out-of-season breeding performance in sheep. Advisors/Committee Members: Umberger, Steven H. (committeechair), Lewis, Gregory S. (committee member), Notter, David R. (committee member).

Subjects/Keywords: Progestational hormones; Synthetic.; LD5655.V855 1993.J222

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APA (6^th Edition):

Jabbar, G. (1993). Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/43419

Chicago Manual of Style (16^th Edition):

Jabbar, Ghulam. “Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes.” 1993. Masters Thesis, Virginia Tech. Accessed April 10, 2021. http://hdl.handle.net/10919/43419.

MLA Handbook (7^th Edition):

Jabbar, Ghulam. “Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes.” 1993. Web. 10 Apr 2021.

Vancouver:

Jabbar G. Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes. [Internet] [Masters thesis]. Virginia Tech; 1993. [cited 2021 Apr 10]. Available from: http://hdl.handle.net/10919/43419.

Council of Science Editors:

Jabbar G. Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes. [Masters Thesis]. Virginia Tech; 1993. Available from: http://hdl.handle.net/10919/43419

Virginia Tech

2. Andrew, Shelley Lewis Jr. Budget Analysis of Spring, Fall with Winter Clean-up, and High-Fertility Fall Lambing Systems in a Simulated Fixed Forage Resource.

Degree: MS, Animal and Poultry Sciences, 1998, Virginia Tech

URL: http://hdl.handle.net/10919/37021

► A successful business needs to generate enough cash to cover expenses, current debt, and family living expenses, pay interest on owned and borrowed capital, maintain… (more)

▼ A successful business needs to generate enough cash to cover expenses, current debt, and family living expenses, pay interest on owned and borrowed capital, maintain productivity, and earn a reasonable return for the operator. Income from sheep production is generally only part of a total farm and nonfarm income. Thus options, opportunity costs, and decisions regarding the sheep production enterprise are not isolated; they affect other agricultural enterprises. Sheep production consistently returns profits to producers, which makes it an enticing agricultural enterprise. There are advantages in raising sheep in Virginia, such as abundant, high-quality forage, moderate climate, pasture improvement, and good access to markets with high demand for lamb. The disadvantages to sheep production are unavailable and inexperienced labor and operators, predators, and inconsistent market demand and supply. Sheep producers have the opportunity to choose which lambing system fits their existing operations and lifestyle. The use of economic analysis enables operator to make sound business management decisions. To compare different lambing systems (spring, fall with winter clean-up, and high-fertility fall) in a systematic way, a simulation model was constructed with a fixed forage resource of 50 acres of pasture including typical Virginia mountain pasture plus various amounts of fescue for stockpiling. The simulation included a production calendar; nutritional requirements for ewes, lambs, and artificially reared triplets; growth rates for lambs; lambing distributions; forage growth; and enterprise budgets including income, costs, and returns. A economic analysis was performed for each lambing system with average prices or with plus or minus one standard deviation for prices of corn, SBOM, and market lambs, and price differentials for market lambs across lambing seasons. Comparisons of each lambing systems produced various results. In spring lambing, only 78 ewes could be maintained on the fixed forage resource, while the fall with winter clean-up and high-fertility fall lambing system each had 115 ewes. This result occurred because of limited forage in July and August and higher nutrient requirements for spring lambing in those months. The overall nutrient requirements were higher in the fall with winter clean-up and high-fertility fall lambing than in spring lambing as a result of the increased ewe and lamb numbers. Concentrate consumption by lambs was also greater for fall with winter clean-up and high-fertility fall lambing than for spring lambing because of the increased numbers of lambs. Because of the low number of ewes and lambs, spring system produced the most hay. Labor costs were highest in fall with winter clean-up lambing because of the two lambing seasons. In the economic analysis system, each lambing was compared. With 10-year average prices for market lambs, corn, and SBOM, high-fertility fall lambing had the greatest income (17,467), followed by fall with winter clean-up lambing (14,695),… Advisors/Committee Members: Notter, David R. (committeechair), Umberger, Steven H. (committee member), Kohl, David M. (committee member), McKinnon, B. R. (committee member).

Subjects/Keywords: Sheep; Lambing Systems; Simualted Models; Forage

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Andrew, S. L. J. (1998). Budget Analysis of Spring, Fall with Winter Clean-up, and High-Fertility Fall Lambing Systems in a Simulated Fixed Forage Resource. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/37021

Chicago Manual of Style (16^th Edition):

Andrew, Shelley Lewis Jr. “Budget Analysis of Spring, Fall with Winter Clean-up, and High-Fertility Fall Lambing Systems in a Simulated Fixed Forage Resource.” 1998. Masters Thesis, Virginia Tech. Accessed April 10, 2021. http://hdl.handle.net/10919/37021.

MLA Handbook (7^th Edition):

Andrew, Shelley Lewis Jr. “Budget Analysis of Spring, Fall with Winter Clean-up, and High-Fertility Fall Lambing Systems in a Simulated Fixed Forage Resource.” 1998. Web. 10 Apr 2021.

Vancouver:

Andrew SLJ. Budget Analysis of Spring, Fall with Winter Clean-up, and High-Fertility Fall Lambing Systems in a Simulated Fixed Forage Resource. [Internet] [Masters thesis]. Virginia Tech; 1998. [cited 2021 Apr 10]. Available from: http://hdl.handle.net/10919/37021.

Council of Science Editors:

Andrew SLJ. Budget Analysis of Spring, Fall with Winter Clean-up, and High-Fertility Fall Lambing Systems in a Simulated Fixed Forage Resource. [Masters Thesis]. Virginia Tech; 1998. Available from: http://hdl.handle.net/10919/37021

Virginia Tech

3. Al-Shorepy, Salih Abdu. Selection to improve spring fertility in a crossbred sheep population.

Degree: PhD, Animal Science, 1995, Virginia Tech

URL: http://hdl.handle.net/10919/40136

► Reproductive and productive performance of a composite sheep population, containing 50% Dorset, 25% Rambouillet and 25% Finn sheep breeding and under selection for ability to… (more)

▼ Reproductive and productive performance of a composite sheep population, containing 50% Dorset, 25% Rambouillet and 25% Finn sheep breeding and under selection for ability to lamb in the fall, was evaluated. Traits considered were spring fertility, faIl litter size, live weights at birth, weaning, and at about 90 and 120 d of age, and scrotal circumference at weaning and at about 90 and 120 d of age. Fertility was defined as 1 or 0 depending upon whether a ewe lambed or failed to lamb, respectively, in fall. Litter size was defined as the number of lambs born per ewe lambing. A total of 1,102 exposures were used. Fertility averaged .59 for adult ewes (3 years and older), .45 for second-lambing ewes and .11 for yearling ewes (12 months old). Mean litter size averaged 1.89 across seasons and ages. Scrotal circumferences (SC) and body weights (WT) were measured at means of65, 96 and 128 d. Data were collected on 1878 lambs over 5 years; 63 sires and 420 dams were represented. Genetic parameters were estimated by restricted maximum likelihood (REML) using various animal models. Heritability estimates for spring fertility ranged from .07 to .11. Litter size heritability was .05 for fall lambing and .10 for all lambings. Heritability estimates for weights from birth to 120 d ranged from .04 to . 19. Heritabilities for SC ranged from .02 to .25. Estimated genetic correlations among weights were large, and ranged from. 77 to unity. The genetic correlations of litter size with birth weight (BWT), 90-d weight (90WT) and 90-d scrotal circumference (90SC) were .17, .33 and .36, respectively. Genetic correlations of spring fertility with BWT, 90WT and 90SC were .22, -.31 and .29, respectively. Mixed model methodology was applied to estimate genetic trends for fertility, litter size, BWT, weaning weight (WWT), 90WT and 90SC resulting from selection for fall lambing. Positive genetic gains in both spring fertility and fall litter size were observed. Rate of increase was higher for fertility than litter size, which was due to direct selection for fertility. Selection for spring fertility did not cause significant correlated changes in BWT, WWT, 90WT or 90SC. Thus, no genetic antagonisms resulted from the selection for fall lambing. Advisors/Committee Members: Notter, David R. (committeechair), Hoeschele, Ina (committee member), Hohenboken, William D. (committee member), Umberger, Steven H. (committee member).

Subjects/Keywords: sheep; reproduction; LD5655.V856 1995.A474

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Al-Shorepy, S. A. (1995). Selection to improve spring fertility in a crossbred sheep population. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/40136

Chicago Manual of Style (16^th Edition):

Al-Shorepy, Salih Abdu. “Selection to improve spring fertility in a crossbred sheep population.” 1995. Doctoral Dissertation, Virginia Tech. Accessed April 10, 2021. http://hdl.handle.net/10919/40136.

MLA Handbook (7^th Edition):

Al-Shorepy, Salih Abdu. “Selection to improve spring fertility in a crossbred sheep population.” 1995. Web. 10 Apr 2021.

Vancouver:

Al-Shorepy SA. Selection to improve spring fertility in a crossbred sheep population. [Internet] [Doctoral dissertation]. Virginia Tech; 1995. [cited 2021 Apr 10]. Available from: http://hdl.handle.net/10919/40136.

Council of Science Editors:

Al-Shorepy SA. Selection to improve spring fertility in a crossbred sheep population. [Doctoral Dissertation]. Virginia Tech; 1995. Available from: http://hdl.handle.net/10919/40136

Virginia Tech

4. Nugent, Russell A., III. Effects of breed and ram exposure on Spring estrous behavior and Summer fertility in domestic ewes.

Degree: MS, Animal Science, 1987, Virginia Tech

URL: http://hdl.handle.net/10919/44057

► The present studies were conducted to check the effects of acute ram introduction into a flock of anestrus ewes in Virginia. Ewes were bled via… (more)

Subjects/Keywords: Sheep; LD5655.V855 1987.N83

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Nugent, Russell A., I. (1987). Effects of breed and ram exposure on Spring estrous behavior and Summer fertility in domestic ewes. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44057

Chicago Manual of Style (16^th Edition):

Nugent, Russell A., III. “Effects of breed and ram exposure on Spring estrous behavior and Summer fertility in domestic ewes.” 1987. Masters Thesis, Virginia Tech. Accessed April 10, 2021. http://hdl.handle.net/10919/44057.

MLA Handbook (7^th Edition):

Nugent, Russell A., III. “Effects of breed and ram exposure on Spring estrous behavior and Summer fertility in domestic ewes.” 1987. Web. 10 Apr 2021.

Vancouver:

Nugent, Russell A. I. Effects of breed and ram exposure on Spring estrous behavior and Summer fertility in domestic ewes. [Internet] [Masters thesis]. Virginia Tech; 1987. [cited 2021 Apr 10]. Available from: http://hdl.handle.net/10919/44057.

Council of Science Editors:

Nugent, Russell A. I. Effects of breed and ram exposure on Spring estrous behavior and Summer fertility in domestic ewes. [Masters Thesis]. Virginia Tech; 1987. Available from: http://hdl.handle.net/10919/44057

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