A proposed functional polymorphism in the ionotropic glutamate receptor AMPA1 (GRIA1) has been reported to influence antral follicle numbers and fertility in cows. Repeat breeder cows that fail to produce a calf in multiple seasons have been reported to have reduced numbers of small (1 to 3 mm) antral follicles in their ovaries. Therefore, we tested the hypothesis that this GRIA1 polymorphism w...

MILK FEVER, also called parturient paresis and parturient hypocalcemia, is an aifection of cows occurring shortly after calving. It is characterized by paralysis of the motor and sensory nervous apparatus. Despite its name, milk fever usually is not accompanied by fever. There is always, however, a marked and rapid lowering of the blood calcium, so that the name "parturient hypocalcemia," which...

Cows in negative energy balance after calving often have reduced reproductive performance, which is mediated by metabolic signals. The objective of these studies was to determine the association of serum metabolites, days to first postpartum ovulation, milk production, cow BW change, BCS, and calf performance with conception date in spring-calving 2- and 3-yr-old beef cows grazing native range....

A total of 135 postpartum suckled zebu cows were assigned randomly at calving to two treatments: cows exposed to vasectomised bulls (Mature Bull Exposure, MBE) and cows not exposed to bulls (No Bull Exposure, NBE) for a period of 150 days postpartum. This study was conducted to determine the influence of bull biostimulation, season and parity on postpartum reproductive performance of Bos indicu...

Oestrous intensity is positively associated with reproductive outcome in high-Abstract This study tested whether strong oestrus symptoms are linked to low lameness score, acceptable pregnancy and calving rates in heifers and first parity dairy cows with a high genetic potential for milk production. In a single Swedish nucleus herd for genetic selection and testing, oestrous intensity was determ...

A year-round grazing system for springand fall-calving cows was developed to compare animal production and performance, hay production and feeding, winter forage composition changes, and summer pasture yield and nutrient composition to that from a conventional, or minimal land system. Systems compared forage from smooth bromegrass-orchardgrass-birdsfoot trefoil pastures for both systems in the ...

The objectives of this work were to compare reproduction and parturition traits of the Criollo breed Romosinuano as straightbred and crossbred cows with Angus and Brahman, to estimate heterosis and direct and maternal genetic breed effects, and to describe calf loss, cow removals from the project, the occurrence of calving difficulty, inadequate calf vigor at birth, and udder problems by cow br...

this study was designed to investigate causes of culling in industrial dairy herds in fars province and to describe the pattern of reason-specific culling with respect to age of animal and interval from calving to culling. a total number of 9 dairy herds were selected for the study and information about culling reasons, birth date, last calving date and culling date was collected for culled cow...

The objectives of this study were to evaluate the functional properties of immunocompetent cells in dairy cows fed diets enriched in n-3 or n-6 polyunsaturated fatty acids during the transition period. Six weeks before calving, 21 primiparous and 27 multiparous pregnant Holstein dairy cows were randomly allotted to 1 of 3 dietary fat treatments: calcium salts of palm oil (Megalac), micronized s...

The objective of this study was to evaluate the relationships between several health disorders: milk fever (MF; hypocalcaemia and parturient paresis), retained placenta (RP; retained foetal membranes), metritis (ME; endometritis and pyometra), ovarian cysts (OC; follicular and luteal cysts), clinical mastitis (CM), and lameness (LS; foot and leg problems) as affecting the reproductive performan...