The aim of this study was to determine differences in residue elimination of amoxicillin (AMX) in cow ́s milk, after intramammary administration of a pharmaceutical preparation of AMX plus potassium clavulanate (CLV), either in healthy or in spontaneous cases of clinical mastitis, and following label instructions or administering the preparation in an extra-label manner. Twelve lactating healthy...

Colostrum samples from 88 Jersey cows were analyzed for concentrations of IgG, IgM, IgA, total solids, specific gravity, and N fractions. Colostrum (50 ml) was sampled from each cow as soon as possible after parturition, and specific gravity was determined immediately using a hydrometer. Samples then were frozen prior to analysis of Ig, fat, and N fractions. Mean concentrations of IgG, IgM, and...

The objective of this study was to investigate if a reduced milking frequency altered the effect of dietary energy restriction on the hepatic transcriptome of grazing dairy cows during early lactation. Multiparous Holstein-Friesian and Holstein-Friesian × Jersey cows (n = 120) were milked twice daily (2×) from calving until 34 ± 6 days in milk (mean ± SD). Cows were then allocated to one of fou...

Heat stress at the time of conception affects the subsequent milk production of primiparous Holstein cows; however, it is unknown whether these effects are maintained across multiple lactations. Therefore, the objective of the current study was to examine the relationship between periconceptional heat stress and measurements of milk production and composition in cows retained within a herd for ...

The objectives of the study were to compare the ovarian activity of Holstein-Friesian (CH HF), Fleckvieh (CH FV) and Brown Swiss (CH BS) dairy cows of Swiss origin with that of Holstein-Friesian (NZ HF) dairy cows of New Zealand origin, the latter being used as a reference for reproductive performance in pasture-based seasonal calving systems. Fifty, second-lactation NZ HF cows were each paired...

Estimates of additive and nonadditive multibreed co-variance components, genetic parameters, and predicted genetic values for first lactation 305-d mature equivalent (ME) milk yield, fat yield, and protein yield were computed using data from a sample of 3316 cows from the Chilean Holstein-other breeds multibreed population. Variances and covariances were estimated by 2-trait REML analyses using...

CASE HISTORY: A herd of Holstein, Jersey, or Holstein-Jersey cross lactating cattle of mixed ages presented with a sudden drop in milk yield in 94/678 cows on 3 October 2014 (Day 0). The herd was located in Gretna in the Derwent Valley (Tasmania, Australia) and had been grazing dryland pasture. CLINICAL FINDINGS: On Day 0 the cows variably showed recumbency, peracute photosensitisation, inflame...

Background: No dairy breed or crossbreed has superior overall performance in all environments; therefore, it is necessary to determine which the most suitable for Mexican tropic and what proportion of European optimum reproduction. Objective: To assess effect Bos taurus (Bt) genes on reproductive Holstein×Zebu (HZ) Brown Swiss×Zebu (BZ) cows, compare these genotypes a dual-purpose production sy...

the objective of the study was to evaluate the uterine histopathological changes in holstein dairy cows, within the range of 90-145 day in milk, with or without clinical history of reproduction system disorders. lactating holstein cows (n =133) with (n=92, 69.17%) or without (n= 41, 30.82%) recorded clinical signs of reproduction diseases were examined for uterine histopathological lesions. the...