Data from six experiments (two with dry cows) were used to predict partitioning of gross energy to CH4 in Holstein cows using selected independent variables, some of which were intercorrelated, and a stepwise backward elimination regression procedure. Methane outputs ranged from 3.1 to 8.3% (mean 5.5) of gross energy intake for 134 dry cow balance trials and from 1.7 to 14.9% (mean 5.2) of gros...

A twoto four-fold increase in corn prices in recent years over historical trends has prompted many questions about alternatives to corn for dairy rations. As corn is a low protein high energy feedstuff, its continued use even with high prices or concern over its partial replacement is mainly confined to rations for lactating cows where meeting the energy requirements of milk production is impor...

The optimum starch content of diets fed to lactating cows is not well defined, but 24% to 26% starch (DM basis) has been suggested (Staples, 2007). Kaiser and Shaver (2006) and Bucholtz (2006), from surveys of high producing (>13,650 kg RHA) dairy farms in Wisconsin (n = 9) and Michigan (n = 18), respectively, reported starch concentrations of diets fed to lactating cow groups ranging from 25% ...

Previous research indicates that high blood urea nitrogen (BUN) concentrations are associated with decreased fertility in lactating dairy cows.This experiment was done to evaluate the effects of equine chorionic gonadotropin (eCG) administration (with or without eCG) on fertility of lactating dairy cows with different levels of BUN subjected to fixed-time artificial insemination (FTAI).Ovulatio...

An experiment was conducted to examine the effect that various isoenergetic diets, containing different quantities of soluble carbohydrate and fiber and different types of starch, have on nitrogen (N) balances. Six lactating dairy cows in early to midlactation consuming grass silage diets with not less than 600 g/kg total DMI as forage were used in the experiment. Four concentrates were prepare...

In two consecutive years, primi- and multiparous, spring-calving Hereford and Hereford x Angus cows (n = 32, yr 1; n = 42, yr 2) were used to determine the effects of supplements and lactational status on forage intake, digestibility, and energy intake. Cows were randomly alloted to treatments after being blocked by age, breed, and weight. Supplements fed during gestation provided .55 kg/d of C...

OBJECTIVE To estimate seroprevalence of Mycobacterium avium subsp paratuberculosis (MAP) infection among adult dairy cows in Colorado and determine herd-level factors associated with the risk that individual cows would be seropositive. DESIGN Cross-sectional observational study. ANIMALS 10,280 adult (> or = 2 years old) dairy cows in 15 herds in Colorado. PROCEDURE Serum samples were test...

The effects of utilizing evaporative cooling system equipped with tunnel ventilation on postpartum ovarian activities, energy balance and milk production of early lactating dairy cows under hot and humid climates were studied from parturition to 22 wk postpartum. Thirty-four crossbred Holstein-Friesian (93.75% HF×6.25% Bos indicus) primiparous cows were randomly assigned to one of two groups. C...

Heat stress has negative effects on pregnancy rates of lactating dairy cattle. There are genetic differences in tolerance to heat stress; Bos taurus indicus (B. t. indicus) cattle and embryos are more thermotolerant than Bos taurus taurus (B. t. taurus). In the present study, the effects of sire and sire breed on conception and embryonic/fetal loss rates of lactating Holstein cows during the Br...

a field study was conducted around pb slag contaminated sites in ibadan, nigeria to assess theintake of trace metals by cows reared around the contaminated sites as indication of heavy metals contamination.levels of pb, cd, cu and zn in blood, milk and faeces were determined in 20 cows exposed to the sites and 20reference cows from uncontaminated areas. chemical analysis of pasture grasses and ...