The objective of this study was to determine the long-term effects of feeding monensin on methane (CH4) production in lactating dairy cows. Twenty-four lactating Holstein dairy cows (1.46 +/- 0.17 parity; 620 +/- 5.9 kg of live weight; 92.5 +/- 2.62 d in milk) housed in a tie-stall facility were used in the study. The study was conducted as paired comparisons in a completely randomized design w...

Several temperature-humidity indexes (THI) have been used to estimate the degree of thermal stress experienced by dairy cows. The present objectives were to develop equations using meteorological variables that predicted rectal temperature of lactating cows in a subtropical environment and compare the goodness of fit of these equations to those using 8 different THI. Rectal temperature was meas...

To establish sustainability in the dairy industry, it is important that cows become pregnant at a biologically optimal time and at an economically profitable interval after calving. In this review, the results obtained from Holstein cattle in an experimental herd for dairy research are summarized. First, the effect of age at first calving of heifers on productive and reproductive performance wa...

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. ...

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...