Document Detail


Weekly bull exchange shortens postpartum anestrus in suckled beef cows.
MedLine Citation:
PMID:  18295874     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The duration of anestrus in cattle was usually shortened when cows were exposed to bulls. The objective of the present experiment was to determine if weekly bull exchange accelerated the resumption of cyclicity in postpartum suckled beef cows. We tested the hypothesis that exposure of postpartum, anestrous, suckled beef cows (extensively managed) to weekly exchange of bulls, accelerates the resumption of cyclicity, compared to continuous exposure to the same bulls. Ninety-one multiparous suckled Hereford and Hereford x Angus cows, <60d postpartum, were assigned to two homogeneous groups. Beginning on December 1st (late spring), the control group (C, n=45) remained with one pair of bulls throughout the breeding period (7 weeks), whereas in the "exchanged" (E, n=46) group two pairs of bulls were exchanged weekly. Based on weekly ultrasonographic examinations of all cows, none had a CL at the start of the experiment and for 2 weeks after the start of bull exposure. However, the accumulated frequency of cows with a CL was greater in group E than in group C cows on week 4 (P=0.024), as well as on weeks 5-7 (P<0.001) after the start of bull exposure. Furthermore, in group E versus group C, there was a higher pregnancy rate 30d after the end of bull exposure (26 of 46, 56.2% vs. 16 of 45, 35.6%; P=0.045). In conclusion, weekly exchange of two pairs of bulls shortened postpartum anestrus in suckled multiparous cows, compared to continuous exposure to a single pair of bulls.
Authors:
V Miller; R Ungerfeld
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2008-03-04
Journal Detail:
Title:  Theriogenology     Volume:  69     ISSN:  0093-691X     ISO Abbreviation:  Theriogenology     Publication Date:  2008 May 
Date Detail:
Created Date:  2008-04-14     Completed Date:  2008-08-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0421510     Medline TA:  Theriogenology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  913-7     Citation Subset:  IM    
Affiliation:
Departamento de Fisiología, Facultad de Veterinaria, Lasplaces 1550, Montevideo 11600, Uruguay.
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MeSH Terms
Descriptor/Qualifier:
Anestrus / physiology*
Animal Husbandry / methods*
Animals
Cattle / physiology*
Corpus Luteum / physiology,  ultrasonography
Female
Male
Postpartum Period
Pregnancy
Sexual Behavior, Animal / physiology

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