Participation in milk-recording programs that provide data for national genetic evaluations of dairy cattle in the United States is voluntary, but the effectiveness of the evaluation system increases with the number of herds that contribute data. To investigate patterns of herd participation in Dairy Herd Improvement (DHI) testing, periods of continuous testing were computed based on the year t...

Fecal samples were collected from 4,361 dairy cows on 91 dairy operations between 26 February and 8 July 1996. Fecal samples were cultured for Escherichia coli O157, and positive isolates were probed for verotoxin-producing genes. A total of 52 (1.2%) fecal samples on 22 (24.2%) operations were positive for verotoxin-producing E. coli O157. Herds in which samples were collected on or after 1 Ma...

........................................................................................................... 6 ORIGINAL ARTICLES ......................................................................................... 8 ABBREVIATIONS ................................................................................................. 9 INTRODUCTION .....................................................

STUDY QUESTION Is increased consumption of dairy foods associated with lower semen quality? SUMMARY ANSWER We found that intake of full-fat dairy was inversely related to sperm motility and morphology. These associations were driven primarily by intake of cheese and were independent of overall dietary patterns. WHAT IS KNOWN ALREADY It has been suggested that environmental estrogens could b...

Farms that purchase replacement breeding cattle are at increased risk of introducing many economically important diseases. The objectives of this analysis were to determine whether the total number of replacement breeding cattle purchased by individual farms could be reduced by improving herd performance and to quantify the effects of such reductions on the industry-level transmission dynamics ...

Objective: The objective was to evaluate the reproductive performance of sex-sorted semen on beef cows and heifers.

Q fever in dairy cattle herds occurs mainly after inhalation of contaminated aerosols generated from excreta by shedder animals. Propagation of Coxiella burnetii, the cause of the disease between ruminant herds could result from transmission between neighbouring herds and/or the introduction of infected shedder animals in healthy herds. The objective of this study were (i) to describe the spati...

Dairy producers and others have been discussing the use of sexed semen for many years. Sexing bovine semen is possible because X-sperm have 3.8% more DNA than Y-sperm. This difference can be identified with a flow cytometer by staining the sperm with a fluorescent dye that binds to the DNA. The technique is reasonably accurate (10% error rate) but still very expensive and slow, which has limite...

no report has been published on the economical losses associated with errors in oestrus detection in cows under iranian intensive dairy management. the following study was carried out to determine the accuracy of oestrus detection by farmers using artificial insemination in shiraz dairy farms. milk samples were collected from 179 holstein milking cows at the time of artificial insemination. mil...

Subfertility problems are encountered frequently in the cattle and buffalo bulls commercially maintained for semen production in dairy farms and under field conditions for natural insemination. Reports are scarce on the incidence of subfertility in breeding bulls, especially in India. The objective of the present study was to assess the incidence of the male reproductive anomalies leading to di...