the aims of this study were to determine some major biochemical alterations observed in first calving cows with udder edema during the periparturient period and to detect some associations between dietary factors and the disease. for that, the concentrations of some electrolytes (na+, k+, cl, ca2+, p and mg2+), lipid (triglycerides and cholesterol) markers and lipoproteins (hdl, ldl and vldl) a...

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...

Productivity of 2-yr-old crossbred cows containing various proportions (0, 1/4 or 1/2) of Brahman breeding was evaluated using 203 spring-calving and 171 fall-calving heifers over a 3-yr period. All heifers were mated to Limousin sires. Percentage of cows exposed to breeding that weaned a calf was the only trait for which a significant crossbred cow group x season of calving interaction was fou...

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...

This review presents genetic, phenotypic, environmental and other factors influencing functional longevity in dairy cattle. High yielding cows show a lower risk of culling than low producing cows. Cows with a lower milk yield have an approximately 2.7 times greater risk of culling as compared to cows with an average milk production. Genetic estimation of the length of productive life is possibl...

The incidence of mortality and culling in Holstein-Friesian heifers from birth through first calving was determined on 19 dairy farms selected from across southern England. The outcome of 1097 calvings was determined. Size (BW, heart girth, crown-rump length and height at withers) and insulin-like growth factor-I concentration of live heifer calves were measured at a mean age of 26 ± 0.7 days (...

The aim of this research was to estimate the influence of environmental factors, such as air temperature and milk production, on reproduction traits of primiparous Polish Holstein-Friesian cows. The following reproduction traits were considered: interval from calving to first insemination, interval from first to last insemination, interval from calving to conception, number of inseminations per...

Dairy heifers only start to produce a return on investment at first calving. The length of the nonproductive rearing period is largely governed by farmer decisions on plane of nutrition and reproduction management. Primary data were collected from 101 dairy farms and a cost analysis workbook developed to calculate individual inputs in each of three periods to determine which management decision...

To analyze the effects of some environmental factors such as herd, year, season of calving, stage of lactation on mastitis incidence, a total of 101147 monthly test day somatic cell counts collected from 13977 Iranian Holstein heifers calved between 2002 and 2006 in 183 herds were used. The event of mastitis in cows was coded as 1 if their somatic cell count at specific test day was greater tha...