The objective of this study was to estimate the relation of body condition score (BCS) near calving to the body condition change in early lactation, the reproductive performance, milk yield and culling rate in the first lactation Estonian Holstein dairy cows. Cows were divided into three groups based on their BCS at calving; thin, BCS ≤3.0 (n=29); moderate, BCS 3.25–3.5 (n= 48); and fat, BCS ≥3...

The objective of the present study was to estimate genetic trends for lactation milk yield, persistency of milk yield, somatic cell count and interval between first and second calving in Holstein dairy cows of Iran. The dataset consisted of 210,625 test day and 25,883 first parity cows with milk yield recorded from July 2002 to September 2007 comprising 97 herds in Iran. Breeding values of anim...

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...

The aim of the present study was to show the distribution of cows by days in milk (DIM) at first AI, effect of DIM at first AI on reproductive performance and some factors influencing DIM at first AI. A total of 767 Holstein Frisian cows that calved from January 2004 to December 2007 in 14 dairy herds were used. The first AI conception rate (FAICR) was 34.0%. Seventy-five percent of the cows we...

Major objectives were to evaluate effects of three schemes of bST-supplementation of Holstein cows (142.8 mg/14 d, POSILAC) during the prepartum and/or postpartum periods through 63 d (±3 d) of lactation. Measures evaluated the potential of treatments to improve body weight (BW) and body condition score (BCS), provoke changes in plasma concentrations of somatotropin (ST) and IGF-I, and improve ...

The present experiment examined the effect of offering either a high- (H) or low- (L) energy-density diet in late gestation and early lactation on physiological parameters, body condition score (BCS) and milk production in early lactation. In all, 40 multiparous Holstein cows were randomly allocated to one of four treatments in a 2 × 2 factorial design, where the factors were H- or L-energy den...

For the current research the records of 62 farms in Isfahan province were available. To estimate genetic and phonotypic trends of reproductive traits such as age at first calving, calving interval, days open and number of insemination to conception rate the records of 63,866 cows including 167793 reproductive records were employed. Farms were covered by Vahdat industrial Agriculturists and Dair...

For the current research the records of 62 farms in Isfahan province were available. To estimate genetic and phonotypic trends of reproductive traits such as age at first calving, calving interval, days open and number of insemination to conception rate the records of 63,866 cows including 167793 reproductive records were employed. Farms were covered by Vahdat industrial Agriculturists and Dair...

The aim of this paper was to determine effects of selected genetic and environmental factors on the concentration of acetone in blood of cows in the first trimester of lactation. The study included 124 Polish Holstein-Friesian primiparous cows born, reared and managed on the same farm. The samples of blood were collected on day 2, 5, 30, 60 and 90 after calving. The highest serum acetone concen...

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...