Document Detail


Short communication: Feed restriction around insemination did not alter birth sex ratio in lactating dairy cows.
MedLine Citation:
PMID:  20965356     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Studies investigating variation in birth sex ratio indicate that the energy status of the dam prebreeding can influence the sex of the subsequent offspring. The Trivers-Willard hypothesis suggests that dams in good condition would produce more male offspring, whereas dams in poor condition (relative to dams in good condition) would produce more female offspring. However, results testing this hypothesis are associative in nature, with no data available from controlled experiments. Hence, this study tested the hypothesis that feed allowance around the time of conception alters birth sex ratio in lactating dairy cows. Cows (n=770 on 2 farms) were randomly allocated to 2 treatments before the seasonal breeding period and offered either unrestricted (UnRes; n=453, across 4 herd replicates) or restricted (Res; n=317, across 3 herd replicates) allowance of fresh pasture for the first 14 d of breeding. Restricted cows responded by reducing milk yields throughout the treatment period and took 3 to 4 wk to recover. The birth sex ratio of resultant offspring was evaluated for cows that conceived in the first 21 d of breeding (UnRes n=234; Res n=142). Birth sex ratio was not different between UnRes and Res treatments. Association analysis, within treatments, identified that cows had a greater odds of producing a male offspring if they had lower milk fat to protein ratio before conception, were in a lower body condition score precalving, and gained condition from calving to the breeding period. No relationship between body condition score prebreeding and birth sex ratio was identified. In the current study, no difference in the birth sex ratio was observed following a short-term feed restriction around the conception. However, alternative indirect measures of energy balance (e.g., milk fat:protein ratio) may be a useful tool when examining the relationships between energy balance in dairy cows and birth sex ratio.
Authors:
S Meier; Y J Williams; C R Burke; J K Kay; J R Roche
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of dairy science     Volume:  93     ISSN:  1525-3198     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-22     Completed Date:  2011-01-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5408-12     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Affiliation:
DairyNZ Limited, Private Bag 3221, Hamilton 3240, New Zealand. susanne.meier@dairynz.co.nz
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MeSH Terms
Descriptor/Qualifier:
Animal Nutritional Physiological Phenomena
Animals
Cattle / physiology*
Dietary Fats / analysis
Energy Metabolism / physiology
Female
Food Deprivation / physiology*
Insemination, Artificial / veterinary*
Lactation / physiology
Milk / chemistry
Milk Proteins / analysis
Sex Ratio*
Chemical
Reg. No./Substance:
0/Dietary Fats; 0/Milk Proteins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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