نتایج جستجو برای: age at first calving

تعداد نتایج: 4943216  

Journal: :Journal of animal science 2014
N McHugh A R Cromie R D Evans D P Berry

Genetic evaluations provide information to aid in breeding decisions that increase long-term performance of animals and herds. However, to date no study has been undertaken to investigate the accuracy of the Irish maternal genetic evaluations in beef cattle. The objective, therefore, of this study was to quantify the relationship between phenotypic performance and measures of genetic merit for ...

Journal: :iranian journal of applied animal science 2014
b. deribe m. taye

a study to evaluate the reproductive performance of abergelle goat was carried out at sekota district of amhara national regional state. on-farm flocks from two peasant associations were monitored for two years to collect data. data collected included identification number of doe and kid, birth / kidding date, kid birth weight, sex of kid, post partum doe weight, litter size, parity of doe. dat...

Journal: :Journal of animal science 1985
V D Toelle O W Robison

Data from 528 male and 645 female progeny of 63 sires were used to estimate genetic correlations between female and male reproductive traits. Data were from two Hereford herds involved in a long-term selection program of the North Carolina Agricultural Experiment Service. Testicular measurements of circumference, diameter, length and volume were obtained on bulls at 205 and 365 d. Testicular gr...

Journal: :Journal of animal science 2005
E E Grings R E Short K D Klement T W Geary M D MacNeil M R Haferkamp R K Heitschmidt

A 3-yr study evaluated late winter (Feb), early spring (Apr), and late spring (Jun) calving systems in conjunction with varied weaning strategies on beef cow and calf performance from Northern Great Plains rangelands. Crossbred cows were randomly assigned to one of three calving systems (on average n= 168.calving system(-1).yr(-1)) and one of two weaning times (Wean 1, 2) within each calving sy...

Journal: :Journal of animal science 1988
W E Neville S V Tucker P R Utley

This 4-yr study was conducted with Angus (A)-sired and Polled Hereford (PH)-sired crossbred heifers that were exposed to either A or medium-frame Brahman (B) bulls from primiparous calvings either as 2- or 3-yr-olds. Each year, heifers were allotted at random within breed composition and age of dam to breeding groups on pasture for an 84-d breeding period that began in late March or early April...

2013
Jessica S. Cooke Zhangrui Cheng Nicola E. Bourne D. Claire Wathes

Age at first calving (AFC) affects the profitability of dairy enterprises. This study examined the relationships between AFC and subsequent fertility, milk production and survival up to third calving in UK Holstein-Friesian heifers; Study 1 comprised 134 consecutively born heifers from the same herd (AFC 764 ± 8 days) and Study 2 contained 445 heifers born on 17 farms (AFC 796 ± 6 days). Growth...

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