This study analyzed genetic and phenotypic variation in plasma GH during lactation in first parity dairy cows. The heritability and repeatability were examined using an algorithm for separation of basal and peak concentrations and different power transformations. Blood samples were obtained 17 times during first parity in 85 Holstein, 67 Red Dane, and 62 Jersey cows and assayed for GH. Each bre...

The objective was to determine whether transfer of fresh or vitrified embryos produced in vitro with sex-sorted semen improves pregnancy and calving rates during summer in lactating dairy cows compared with artificial insemination (AI). Lactating dairy cows (n=722) were enrolled during summer months at 2 commercial dairies in Central Texas and randomly assigned to 1 of 3 treatments: AI with con...

S ADSA Student Affiliate Division * Author Presenting Paper Original Research/Independent Study Undergraduate Paper Presentations 957 The luteolytic potential of reduced doses of prostaglandin. J. Brinkerhoff*, R. Silcox, J. Donley, and C. Kubo, Brigham Young University, Provo, UT. Prostaglandin (PGF) and its analogs have greatly contributed to managing the reproductive performance of dairy her...

The transition from pregnant, non-lactating to non-pregnant, lactating is too often a disastrous experience for the cow. Most of the metabolic diseases of dairy cows milk fever, ketosis, retained placenta, and displacement of the abomasum occur within the first 2 wk of lactation. In addition to metabolic disease, the majority of infectious disease experienced by the dairy cow, especially mastit...

the present study was conducted to evaluate the effects of extruded linseed on milk production,dry matter intake and reproduction performance of 300 holstein lactating cows (35±15 days in milk;41±9/8 kg/day of milk production). cows were placed in a completely randomized design of 2treatments (concentrate containing 7 percent of extruded linseed vs. control), (150 cows pertreatment). cows were ...

Many dairy cows in the developed world are now housed exclusively indoors with fewer than 5% of the 10 million lactating cows in the United States having access to pasture during the grazing season. Indoor housing systems are designed to meet biological needs for food, water, hygiene, and shelter, but surveys of public and farmer opinion suggest that people think that pasture access is also imp...

The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]glucose i.v. infusion in lactating dairy cows. Sample enrichments were analysed by gas chromatography/mass spectrometry. Linearity (enriched solutions) and specificity (enriched plasma) were good: for enrichments ranging between 1.6 and 6.3 mol% excess, the slopes were about 1 and the ordinates at th...

The transition from pregnant, non-lactating to non-pregnant, lactating is too often a disastrous experience for the cow. Most of the metabolic diseases of dairy cows milk fever, ketosis, retained placenta (RP), and displacement of the abomasum occur within the first two wk of lactation. In addition to metabolic disease, the majority of infectious disease experienced by the dairy cow, especially...

this experiment was conducted to investigate the effect of feeding frequency and oil supplementation to the diet on performance and feeding behavior of lactating dairy cows. twenty four lactating holstein cows, 12 primiparous, (bw= 626±58 kg and dim= 195±44 day) and 12 multiparous, (bw= 617±25 kg and dim= 207±39 day) were randomly assigned to four diets contained 2.5 percent supplemental oil or...