Bovine viral diarrhoea virus (BVDV) is an important pathogen of dairy cattle. In this study, bulk milk samples representing a total of 4105 milking cows, from 18 dairy cattle herds in the suburb of Mashhad- Iran, were tested for presence of BVDV by the use of a nested reverse transcription polymerase chain reaction (Nested RT- PCR) assay. Non of the cows in the herds had been vaccinated against...

BACKGROUND Results regarding the use of bovine somatotropin for enhancing fertility in dairy cattle are variable. Here, the hypothesis was tested that a single injection of a sustained-release preparation of bovine somatotropin (bST) during the preovulatory period would improve pregnancy success of lactating dairy cows at first service. RESULTS The first experiment was conducted in a temperat...

Dairy cows enter a period of energy insufficiency after parturition. In liver, this energy deficit leads to reduced expression of the liver-specific GH receptor transcript (GHR1A) and decreased GHR abundance. As a consequence, hepatic processes stimulated by GH, such as IGF-I production, are reduced. In contrast, adipose tissue has been assumed to remain fully GH responsive in early lactation. ...

A number of reproductive parameters are altered in lactating dairy cows including: twinning rate, expression of estrus, conception rate, pregnancy loss, and incidence of anovulation. We hypothesized that the high feed consumption associated with lactation has fundamentally altered reproductive physiology due to increased metabolism of steroids. We evaluated liver blood flow and steroid metaboli...

Twenty-four multiparous Holstein cows were used in six 4×4 Latin squares with 28day periods to determine inclusion rates for wet corn gluten feed (WCGF) in diets for lactating dairy cows. Cows were housed in a tie-stall barn and fed diets to meet or exceed NRC (1989) nutrient requirements. Experimental treatments were 1) control, 2) WCGF constituting 20%, 3) WCGF constituting 27.5%, and 4) WCGF...

The aim of this study was to examine whether increased frequency of luteinizing hormone (LH) pulses influences luteal progesterone (P4) secretion by measuring progesterone concentrations at the secreted (caudal vena cava) and circulating levels (jugular vein) in lactating dairy cows. Cows received six intravenous administrations of 2.5 μg of GnRH (gonadorelin acetate, n=4) or 2 ml saline (n=3) ...

BACKGROUND The prevalence and the clinical consequences of subacute ruminal acidosis (SARA) in dairy cows are still poorly understood. In order to evaluate the prevalence of SARA, 26 German dairy farms were included in a field study. In each herd, between 11 and 14 lactating dairy cows were examined for their ruminal pH using rumenocentesis. Milk production data and farm management characterist...

The nutrient contents of perennial ryegrass (Lolium perenne L.) and alfalfa (Medicago sativa L.) are reasonably similar. Despite similarities, the lactation performance of dairy cows fed perennial ryegrass has not been compared with the lactation performance of dairy cows fed alfalfa. The present study was implemented to compare the performance of lactating cows fed alfalfa or perennial ryegras...

The objective of the present study was to compare the efficacy of conventional and extendedintramammary (IMM) therapy of persistent subclinical mastitis in lactating dairy cattle using nafcillinpenicillin-dihydrostreptomycin combination (NPD). Sixty-five dairy cows with 126 infected quarters were enrolled in the study. Infected cows were allocated randomly to 1 of 3 different treatment regimens...