four hundered and ninety five (495) smallholder dairy farms active in 52 villages of different cities in chaharmohalo bakhtiari province, keeping 1321 lactating within a total of 2811 mature cows (lactating and dry) were used. these herds were taken during winter 2009 to summer 2010 to assess some of the production, reproductive and economic performance traits under smallholder management syste...

Two selection goals of inclusion or exclusion of calving interval (CI) in the selection goal function for Holstein cows in Iran, besides milk yield, milk fat percentage, and milk protein percentage, were studied. Four selection indices were composed of using the information on production traits, CI and / or days from calving to first insemination (DFI). The results of the predicted genetic grow...

A better understanding of changes in plasma amino acid (AA) concentrations during the transition period may help optimize nutrition to improve health, welfare, and production dairy cows. The aim this study was assess AA Holstein cows first-lactation heifers. Blood samples for analysis were collected from tail vein/artery 9 multi- 8 primiparous 3 weeks prior at 1, 2, post-calving. Concentration ...

The objective was to investigate the effect of different dry cow feeding strategies on the degree of ketonemia postpartum. Epidemiologic studies provide evidence of an association between elevated β-hydroxybutyrate (BHBA) concentrations in postpartum dairy cows and a decreased risk for reproductive success as well as increased risk for several diseases in early lactation, such as displacement o...

The aim of this study was to evaluate the effect of body weight (BW) change during the early postpartum period and BW on day 50 post partum on the subsequent expression of estrus and fertility at first insemination before day 90 post partum. The data were derived from 1036 postpartum cows reaching 90 days in milk. The following data were recorded for each animal: lactation number, daily milk pr...

Lameness of dairy cattle is an economic and welfare issue. It is the third most important health related economic loss facing the dairy industry, following fertility and mastitis. Most economic loss due to lameness results from costs of premature culling, veterinary treatment, increased labor, discarded milk, prolonged calving interval, and reduced milk production (Kossaibati and Esslemont, 199...

Efficient pasture-based milk production systems require a compact calving pattern aligned to the onset of the grazing season, a 365-day calving interval and low culling rates for infertility. Achievement of these targets requires high herd reproductive performance. While high genetic merit Holstein cows produce more milk in grass-based systems their fertility is compromised. Management of the m...

Mastitis is one of the most important diseases affecting production and reproductive efficiency dairy cows. The objective this study was to estimate prevalence subclinical mastitis (SCMA) its effects on performance in postpartum In a cross-sectional survey, sample cows (n = 200) within their 10-40 days milk from smallholder farms 159) were selected tested for SCMA using California Test. They cl...

The objective of this study was to investigate the association of polymorphisms at the STAT5A and FGF2 gene loci with fertility, lactation milk yield and lameness in dairy cattle. Five hundred and eighteen primiparous Holstein cows were included in the study. Several reproductive traits were considered including conception rate (0/1) at first insemination, conception rate (0/1) in a 305-day lac...

The objective of this study was to determine how the concentration of milk urea (MU) and FPCM production affect reproduction in selected Holstein dairy herds in the Czech Republic. A retrospective, observational study comprising analyses of individual cow records from monthly dairy herd improvement (DHI) milk tests including milk urea (MU) concentration was conducted in six commercial Holstein ...