Skip to main content
ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #110607
Title: PROFITABILITY OF ESTROUS SYNCHRONIZATION WITH NATURAL SERVICE

Author
item Geary, Thomas
item FUNSTON, R - MONTANA EXTENSION SERVICE
item Grings, Elaine
item Bellows, Robert
item Short, Robert

Submitted to: Research Update for Fort Keogh Livestock and Range Research Laboratory
Publication Type: Other
Publication Acceptance Date: 6/23/1999
Publication Date: N/A
Citation: GEARY, T.W., FUNSTON, R.N., GRINGS, E.E., BELLOWS, R.A., SHORT, R. PROFITABILITY OF ESTROUS SYNCHRONIZATION WITH NATURAL SERVICE. RESEARCH UPDATE FOR FORT KEOGH LIVESTOCK AND RANGE RESEARCH LABORATORY. 1999. p. C7.1-2.

Interpretive Summary: Productivity and reproductive performance of beef cows that were bred natural service following synchronization of estrus are being evaluated in 7 beef herds located in Montana and Colorado. Herds range in size from 60 head to 1400 head and include breeding seasons that range in length from 32 to 75 days. One-half of the cows 4herds received the Select Synch protocol at the onset of the breeding season and half of the cows received no treatment. The cows in the other 3 herds received either the Select Synch protocol or a single injection of prostaglandin (PGF) 7 d after the onset of breeding. The Select Synch protocol includes administration of gonadotropin releasing hormone (GnRH) followed one week later by administration of PGF. Two days prior to administration of prostaglandin, cows were exposed to bulls at a ratio of one bull pr 14 to 30 cows (varied by herd). Parameters measured to date include pregnancy rate. Calving date and subsequent rebreeding performance of cows, and calf age, weight and value at weaning will also be evaluated. Pregnancy rates of synchronized cows in one of the Colorado herds were 20 percent higher than pregnancy rates of the non- synchronized cows using a 50-day breeding season. Among cows that were pregnant, the average calving date was 7 days earlier among synchronized cows. Pregnancy rates were similar for the Montana herds used in the study. We are awaiting the end of the calving seasons to evaluate the average calving date among the cows in these herds.

Technical Abstract: Productivity and reproductive performance of beef cows that were bred natural service following synchronization of estrus are being evaluated in 7 beef herds located in Montana and Colorado. Herds range in size from 60 head to 1400 head and include breeding seasons that range in length from 32 to 75 days. One-half of the cows 4herds received the Select Synch protocol at the onset of the breeding season and half of the cows received no treatment. The cows in the other 3 herds received either the Select Synch protocol or a single injection of prostaglandin (PGF) 7 d after the onset of breeding. The Select Synch protocol includes administration of gonadotropin releasing hormone (GnRH) followed one week later by administration of PGF. Two days prior to administration of prostaglandin, cows were exposed to bulls at a ratio of one bull pr 14 to 30 cows (varied by herd). Parameters measured to date include pregnancy rate. Calving date and subsequent rebreeding performance of cows, and calf age, weight and value at weaning will also be evaluated. Pregnancy rates of synchronized cows in one of the Colorado herds were 20 percent higher than pregnancy rates of the non- synchronized cows using a 50-day breeding season. Among cows that were pregnant, the average calving date was 7 days earlier among synchronized cows. Pregnancy rates were similar for the Montana herds used in the study. We are awaiting the end of the calving seasons to evaluate the average calving date among the cows in these herds.