The data on age at first calving for 539 records of crossbred cows differentfilial/genetic groups were considered the present investigation. These crossbreds belonged to eightfilial/genetic (F1, F2, F3, F4, F5, F6, F7 and F8) maintained Livestock Experiment StationQadirabad District Sahiwal from 1991 2014 (24 years). duration 24 year was divided into 6periods (P1, P2, P3, P4, P5 P6) four years ...

In a 7-year longitudinal study 292 Bovelder beef cows in a restricted breeding system in South Africa were observed from 1 to 2 days before their first breeding season, when reproductive tract scoring (RTS, scored from 1 to 5) was performed, until weaning their 5th calves. The objective was to determine whether pre-breeding RTS in heifers is a valid tool to predict long-term reproductive perfor...

Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The appli...

in this study 495 smallholder dairy farms in 52 villages of different township in southwestern province of iran (chaharmohal and bakhtiari province) included 1321 lactating cows and 2811 total mature cows (lactating and dry) during winter 2009 to summer 2010 were used to estimate economic opportunities insmallholder dairy farms. questionnaire survey was used to collect data from last year infor...

Calving records (n = 6,763) obtained from first, second, and third parities of 3,442 spring-calving, Uruguayan Aberdeen Angus cows were used to estimate heritabilities and genetic correlations for the linear trait calving day (CD) and the binary trait calving success (CS), using models that considered CD and CS at 3 calving opportunities as separate traits. Three approaches were defined to hand...

Data on the reproductive traits of dairy heifers were analyzed using event-time techniques. Traits analyzed were age at first calving (n = 4631), days to first breeding, and days open (n = 1992) during the first lactation. A proportional hazard model was used that included fixed effects of herd-year, year-season, breed type, herd weight, and heifer weight. Body weights were recorded at 390 d of...

the objective of this study was to determine cows with subclinical ketosis (sck) with metabolic profile test and subsequent health and productive performances compared to cows without sck. ninety six holstein dry cows were blocked within parity for similar expected calving dates. blood samples were drawn from tail vein 1wk before calving and 1wk after calving. nefa and bhba concentrations were ...