Studies on genetics of heat tolerance in dairy cattle with reduced weather information via cluster analysis.
O. Ravagnolo,Ignacy Misztal +1 more
TLDR
The objective of this study was to explore the possibility of reducing the number of weather stations for studies on genetics of heat tolerance in dairy cattle, and the similarity of information from 21 Georgia weather stations was analyzed by cluster analysis.About:
This article is published in Journal of Dairy Science.The article was published on 2002-06-01 and is currently open access. It has received 34 citations till now. The article focuses on the topics: Weather station.read more
Citations
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Journal ArticleDOI
Major Advances Associated with Environmental Effects on Dairy Cattle
TL;DR: Improved understanding ofPhotoperiod effects on cattle has allowed producers to maximize beneficial effects of photoperiod length while minimizing negative effects and better understand the genetic basis of heat-stress sensitivity and tolerance.
Journal ArticleDOI
Temperature-Humidity Indices as Indicators of Milk Production Losses due to Heat Stress
TL;DR: Indices with higher weights on humidity were best in the humid climate, whereas indices with larger weights on temperature were the best indicators of heat stress in the semiarid climate.
Journal ArticleDOI
The effects of heat stress in Italian Holstein dairy cattle
Umberto Bernabucci,Stefano Biffani,Laura Buggiotti,Andrea Vitali,Nicola Lacetera,Alessandro Nardone +5 more
TL;DR: The negative effect of THI on production traits indicates that first-parity cows are less sensitive to heat stress than multiparous cows, suggesting that heat tolerance selection should be included in the selection objectives.
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Effect of solar radiation on dairy cattle behaviour, use of shade and body temperature in a pasture-based system
TL;DR: In this article, the authors compared the behavior and body temperature of pastured dairy cattle kept in 1of 4 treatments: no shade or free access to shade that blocked either 25, 50 or 99% of solar radiation (n = 3 groups per treatment, 3 animals/group).
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Impact of heat stress on conception rate of dairy cows in the moderate climate considering different temperature–humidity index thresholds, periods relative to breeding, and heat load indices
TL;DR: The results indicate that the CR of dairy cows raised in the moderate climates is highly affected by heat stress, and the mean THI was the most sensitive heat load index relating to CR.
References
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Journal ArticleDOI
Genetic Component of Heat Stress in Dairy Cattle, Development of Heat Index Function.
TL;DR: Production data obtained from AIPL USDA included 119,337 first-parity, test-day records of 15,012 Holsteins from 134 Georgia farms collected in 1990 to 1997 and the temperature-humidity index calculated with the available weather information can be used to account for the effect of heat stress on production.
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Genetic Component of Heat Stress in Dairy Cattle, Parameter Estimation
O. Ravagnolo,Ignacy Misztal +1 more
TL;DR: The authors' data included 119,205 first-parity, test-day records from 15,002 Holsteins in 134 Georgia farms with temperature and humidity data from 21 weather stations throughout Georgia, finding joint selection for heat tolerance and production is possible.
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Use of test day yields for genetic evaluation of dairy sires and cows
Ewa Ptak,L.R. Schaeffer +1 more
TL;DR: Genetic evaluations based on test day yields offer many advantages over those based on 305-day lactations including better modeling of factors affecting yields, no need to extend records, and possibly greater accuracy of evaluations.
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A multiple-trait herd cluster model for international dairy sire evaluation.
Kent A. Weigel,R. Rekaya +1 more
TL;DR: The herd cluster model is intuitively appealing, because genetic merit of an animal is predicted for each unique environment or management system, regardless of country borders, and is computationally feasible for large data sets.
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Application of Contemporary Methods for the Use of International Data in National Genetic Evaluations
Georgios Banos,A Sigurdsson +1 more
TL;DR: A system that combines information from several countries and produces routine international evaluations of dairy bulls is described, and possible ways of utilizing such international information in national breeding programs are presented.