Genetics of lactation persistency
نویسندگان
چکیده
منابع مشابه
Genetic evaluation and best prediction of lactation persistency.
Cows with high persistency tend to produce less milk than expected at the beginning of lactation and more than expected at the end. Best prediction of persistency was calculated as a function of a trait-specific standard lactation curve and a linear regression of test-day deviations on days in milk. Regression coefficients were deviations from a balance point to make yield and persistency pheno...
متن کاملNutritional Strategies to Improve Lactation Persistency in Dairy Ewes
Milk production is largely dependent on the shape of the lactation curve. Relevant elements of the lactation pattern are the peak yield, which represents the maximum milk yield during the lactation, and the lactation persistency, which expresses the ability of animals to maintain a reasonably constant milk yield after the lactation peak (Figure 1). Thus, persistent animals are those that show f...
متن کاملMammary apoptosis and lactation persistency in dairy animals.
The decline in milk yield after peak lactation in dairy animals has long been a biological conundrum for the mammary biologist, as well as a cause of considerable lost income for the dairy farmer. Recent advances in understanding the control of the mammary cell population now offer new insights on the former, and a potential means of alleviating the latter. The weight of evidence now indicates ...
متن کاملExtended lactation in dairy cows: effects of milking frequency, calving season and nutrition on lactation persistency and milk quality.
Twelve spring-calving and twelve winter-calving cows were managed for extended lactation cycles of 18-months duration, with the former group then completing a second extended lactation. Half of the cows were fed according to standard management practice for the herd; the other half received supplementary concentrate from week 9 of lactation onwards. Commencing at the same time, half of the udde...
متن کاملAnalysis of Persistency of Lactation Calculated from a Random Regression Test Day Model
Persistency of lactation is the ability of a cow to continue producing milk at a high level after the peak of her lactation. Differences in persistency, if not properly accounted for, reduce accuracy of genetic evaluation when incomplete records are used. Persistency has also direct economic value. Reduction of feed, health and reproductive costs are the major factors which favour more persiste...
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ژورنال
عنوان ژورنال: BSAP Occasional Publication
سال: 1999
ISSN: 0263-967X,2053-5953
DOI: 10.1017/s1463981500043090