The upper respiratory tract (URT) hosts a complex microbial community of commensal microorganisms and potential pathogens. Analyzing the composition and nature of the healthy URT microbiota and how it changes over time will contribute to a better understanding of the pathogenesis of pneumonia and otitis. A longitudinal study was conducted including 174 Holstein calves that were divided in four ...

Two point mutations were identified within the gene encoding bovine CD18 in a Holstein calf afflicted with leukocyte adhesion deficiency (LAD). One mutation causes an aspartic acid to glycine substitution at amino acid 128 (D128G) in the highly conserved extracellular region of this adhesion glycoprotein, a region where several mutations have been found to cause human LAD. The other mutation is...

A survey of 715 Holstein dairy farms in Pennsylvania was used to construct demographics for the average Holstein dairy farm. The average Holstein dairy farm was composed of 69 lactating cows; 11 nonlactating, pregnant cows; 44 heifers; and 18 calves. Milk production averaged 27.3 kg (60.0 lb). Crop area averaged 73.6 ha. Milk production, crop area and type, average county yields, and herd anima...

We measured changes in plasma ghrelin and GH concentrations in mature Holstein cows and 3-mo-old female Holstein calves fed at scheduled times. Our objective was to determine the characteristics of ghrelin secretion in dairy cattle and its influence on GH. Animals were fed at 0800 and 1600 for 2 wk before and during experiments. Plasma was sampled for 24 h at 2-h intervals in Exp. 1. In mature ...

Parasitic Gastroenteritis(PGE) Penrith diagnosed PGE in a 10-week-old Limousin-X calf which had been at pasture for three weeks before developing diarrhoea. Parasitological examination revealed 5100 trichostrongyle eggs per gram faeces and 1700 coccidial oocysts. Langford diagnosed PGE on eight occasions in six to twelve month old calves Trichostrongyle sp. worm egg counts of up to 4,550 epg we...

This study aimed to investigate the effects of insulin resistance (IR) during the close-up dry period on the metabolic status and performance of dairy cows as well as to determine the effects on body weight (BW) and metabolic status of their calves. An insulin tolerance test (ITT) was conducted by administering 0.05 IU/kg BW of insulin to 34 multiparous Holstein cows at 3 weeks prepartum. Blood...

The hemostatic properties of platelets to a large degree determine the activity metabolic processes that have great biological significance especially in early ontogeny. This study was conducted on 43 calves Holstein breed during phase milk-vegetable diet. It found observation period indicators were stable between 31 and 60 days life, platelet aggregation weakened. In blood there slight increas...

Male Holstein calves (n = 120) purchased from local dairy farms were fed one of three calf milk replacers for 42 d. Experimental milk replacers were formulated to contain whey protein concentrate (WPC) as the primary protein source or WPC plus 5% spray-dried bovine plasma (SDBP) or spray-dried porcine plasma (SDPP). The SDPP was heated to remove heat-insoluble materials and provide products wit...

in order to compare the effects of different weaning strategies on feed intake, structural growth measurement and health, blood metabolites and economic efficiency of young dairy calves, twenty four female holstein calves were used. calves after birth were randomly assigned into one of three weaning strategy as follow: 1) weaning based on feed intake, 2) weaning based on weight gain (30 kg weig...

Gender of the calf whose birth initiates lactation could influence whole lactation milk yield of the dam due to hormonal influences on mammary gland development, or through calf gender effects on gestation length. Fetal gender could influence late lactation yields because cows become pregnant at peak lactation. The effects of calf gender sequences in parities 1-3 were assessed by separately fit...