Influence of age at first calving in a continuous calving season on productive, functional, and economic performance in a Blonde d’Aquitaine beef population1
نویسندگان
چکیده
منابع مشابه
G enetic relationships between calving date, calving interval, age at first calving and type traits in beef cattle
In this paper the genetic relationships between major reproductive traits in beef cattle (Calving Date, Calving Interval and Age at First Calving) and type traits have been estimated to evaluate the usefulness of type classification in predicting reproductive performance in beef cattle. We estimated favourable genetic correlations between Calving Interval and type traits ranging from 2 0.027 to...
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Because of difficulties in data collection and analysis, in most breeds there have been limited ways to evaluate fertility in females on a between-herd basis. The objective of this study was to determine the heritabilities (direct and maternal) for CD (calving day) and AFC (age at first calving) in American Angus heifers and to evaluate the potential for using these traits in genetic improvemen...
متن کاملThe Effect of Age at First Calving and Calving Interval on Productive Life and Lifetime Profit in Korean Holsteins
This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of ...
متن کاملAnalysis of milk production, age at first calving, calving interval and economic parameters in dairy cattle management
The objective of this study was to evaluate main indicators of milk production on total 60 commercial dairy herds from the Czech Republic during a 9-yr period (2006-2014). Breakeven points and sensitivity analysis were used and associations of age at first calving (AFC), milk yield (MY) and calving interval (CI) were analyzed. Lowest AFC≤749 d showed the highest fertility, the lowest death rate...
متن کاملBreeding Season Length Versus Calving Percentage in Beef Cattle Herds
Long breeding seasons result in long calving seasons. This results in calvings distributed through a range of environmental and nutritional conditions and a disparity in calf maturity at any planned weaning time. It also results in cows entering their period of maximal nutritional requirements over the same range of environmental conditions. Attempts to increase cow and calf productivity often ...
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ژورنال
عنوان ژورنال: Journal of Animal Science
سال: 2018
ISSN: 0021-8812,1525-3163
DOI: 10.1093/jas/sky271