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United States Department of Agriculture

Agricultural Research Service

Title: Rebreeding the First Calf Heifer

Authors
item Funston, R - MONTANA EXTENSION SERVICE
item Geary, Thomas

Submitted to: Research Update for Fort Keogh Livestock and Range Research Laboratory
Publication Type: Other
Publication Acceptance Date: June 23, 2000
Publication Date: June 23, 1999
Citation: FUNSTON, R.N., GEARY, T.W. REBREEDING THE FIRST CALF HEIFER. RESEARCH UPDATE FOR FORT KEOGH LIVESTOCK AND RANGE RESEARCH LABORATORY. 1999. p. C11.1-5.

Interpretive Summary: Several management decisions affect the ability of the first calf to breed again as a two-year old and remain in the herd. This article discusses the importance of several of those variables. Heifers require a longer period of time than mature cows to recover from calving before they will return to estrous cyclicity and can be rebred. Calving the heifers 20 to 30 days earlier than the cow herd is a recommended practice. Feeding a balanced ration that meets a heifers needs during the last trimester of pregnancy through the breeding season is critical. Feeding inadequate energy and protein either precalving or postcalving has decreased subsequent pregnancy rates up to 26%. Changes in body condition scores before and after calving can be used to monitor if nutritional needs are being met. Heifers should be bred to bulls with known genetic merit for low birth weight or calving ease to minimize dystocia. In addition, if obstetrical assistance is suspected during calving, it should be administered early to prevent delays in return to cyclicity. Use of an ionophore in the postpartum diet to increase feed efficiency, control coccidiosis and improve reproductive performance has been demonstrated. Short term (48 hour) calf removal, estrous synchronization protocols that utilize progestins or gonadotropin releasing hormone (GnRH), and bull exposure postcalving have also decreased the postpartum anestrous interval in cows and heifers.

Technical Abstract: Several management decisions affect the ability of the first calf to breed again as a two-year old and remain in the herd. This article discusses the importance of several of those variables. Heifers require a longer period of time than mature cows to recover from calving before they will return to estrous cyclicity and can be rebred. Calving the heifers 20 to 30 days earlier than the cow herd is a recommended practice. Feeding a balanced ration that meets a heifers needs during the last trimester of pregnancy through the breeding season is critical. Feeding inadequate energy and protein either precalving or postcalving has decreased subsequent pregnancy rates up to 26%. Changes in body condition scores before and after calving can be used to monitor if nutritional needs are being met. Heifers should be bred to bulls with known genetic merit for low birth weight or calving ease to minimize dystocia. In addition, if obstetrical assistance is suspected during calving, it should be administered early to prevent delays in return to cyclicity. Use of an ionophore in the postpartum diet to increase feed efficiency, control coccidiosis and improve reproductive performance has been demonstrated. Short term (48 hour) calf removal, estrous synchronization protocols that utilize progestins or gonadotropin releasing hormone (GnRH), and bull exposure postcalving have also decreased the postpartum anestrous interval in cows and heifers.

Last Modified: 10/25/2014
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