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Sixteen prepubertal Holstein Friesian heifers were used to study the effect of long-term administration of bovine GH (bGH) on mammary development in intact and ovariectomized heifers. Eight heifers were ovariectomized at 2.5 months of age. Four intact and four ovariectomized heifers received subcutaneous injection of bGH (15 mg/day) for 15 weeks starting at(More)
The effect of stocking rate on the acquisition of Ostertagia ostertagi infection and performance of yearling calves grazing a marshland area in the southwest of Jutland (Denmark) was examined. During the early part of the grazing season, when grass growth was high and pasture infectivity low, there was little stocking rate effect on performance. However,(More)
Available evidence concerning the relationship between growth rate, mammary growth and milk yield in heifers leads to these conclusions: 1) Increased growth rate due to high feeding level before puberty onset can lead to reduced pubertal mammary growth and reduced milk yield potential. 2) Increased growth rate due to high feeding level after puberty and(More)
The lactational variation in milk protein composition and renneting properties and their relationship to the cow's body condition at calving were investigated in 39 Danish Holstein first lactation cows fed on a well balanced standard diet. All milk characteristics measured were significantly affected by stage of lactation (P < 0.01). Casein as a proportion(More)
Nine pairs of identical twins were used to examine the effect of exogenous bovine somatotropin on mammary growth and development in dairy heifers. One twin received a daily subcutaneous injection of somatotropin (20 IU) and the other received excipient. Treatments commenced at 8.0 mo of age (179 kg live weight) and continued for 15.6 wk, at which time(More)
The main purpose of this experiment was to study the importance of time of turnout on the epidemiology and impact of ostertagiasis in calves pastured for the first time. When time of turnout onto permanent pasture was postponed from mid-May to mid-June, fewer overwintered larvae were picked up and re-contamination of pastures was markedly diminished.(More)
This paper describes clinically manifest infections occurring as early as June and early July in first-season grazing calves in Denmark during the period 1972-1987. Two severe outbreaks in 1976, included in our experiments, were studied in detail. Herbage infectivity was particularly high in grass tufts surrounding cow pats that were present in high numbers(More)
Computed tomography scanning is introduced as a new technique to quantify parenchymal tissue of heifer mammary glands. Tissue types with different densities attenuate x-rays differently, and computed tomography is based on computer processing of such x-ray attenuation data. Different tissue types can be quantified by summation of defined x-ray attenuation(More)