Fertility in Dairy Cows Managed for Calving Intervals of 12,15 or 18 Months
نویسندگان
چکیده
منابع مشابه
Trends in calving ages and calving intervals for dairy cattle breeds in the United States.
Trends since 1980 for calving age and calving interval, 2 factors that influence herd life, were examined by parity for 5 breeds of US dairy cattle. Calving data were from cows with records that passed edits for USDA genetic evaluations and were in herds that remained on Dairy Herd Improvement test. First-calf heifers calved at progressively younger ages over time, but the age decline was less ...
متن کاملNutrition and fertility in dairy cows.
Introduction It is now widely recognised that reduced fertility in dairy herds is one of the most important factors affecting producer profitability. Roche (2006) has defined the effect of infertility on profitability as: (i) prolonged calving interval with fewer calves and less milk per cow; (ii) increased replacement costs; (iii) increased labour, semen and veterinary bills; and (iv) an exten...
متن کاملFertility in dairy cows: bridging the gaps.
Dairy cattle are an integral part of agriculture worldwide, providing many products in addition to milk for the human population. The efficient production of these products is of utmost importance and high reproductive performance is absolutely crucial to this. In September 1999, Dr Michael Diskin led a committee (Dr Joseph M. Sreenan, Prof James Roche, Prof Maurice Boland and Dr Diarmuid O’Cal...
متن کاملFertility in High Yielding Dairy Cows
Introduction Genetic progress coupled with improved nutritional management has resulted in many more cows that can produce over 8,500 litres per 305 day lactation. This upward trend in production over the past 30 years has been accompanied by a steady decline in fertility, with first service conception rates often falling below 40%. Over the same period, there have been considerable changes to ...
متن کاملEstimation of Economic Values for Fertility, Stillbirth and Milk Production Traits in Iranian Holstein Dairy Cows
The objective of present study was to derive the economic values for number of inseminations to conception, calving interval, milk yield and stillbirth, using economic data of 10 Iranian Holstein herds. The economic values were derived by using the profit function methods and differentiating a profit equation with respect to the traits of interest. The cow fertility costs herd amortization or r...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Acta Veterinaria Scandinavica
سال: 1998
ISSN: 1751-0147
DOI: 10.1186/bf03547794