AIMS: To investigate factors associated with pregnancy rate in a number of herds of contract rearing replacement dairy heifers. These factors included the average daily gain of a heifer mob, the average bodyweight of the mob at the start of grazing, the number of heifers in the mob, the length of the grazing period, the breed of heifers, the grazing season and the region from where the heifers ...

Livestock species can be affected by different types of genetic defects. Recently, we are faced with genetic defects in dairy cattle such as bovine leukocyte adhesion deficiency (BLAD) and complex vertebral malformation (CVM) both are autosomal recessive defects leads to an inherited lethal disease in Holstein breed. BLAD is caused by a deficiency in leukocyte surface glycoproteins known as int...

This dissertation summarises the findings of two separate studies relating to the epidemiology of bovine viral diarrheoa virus in New Zealand dairy herds. The objective of the first study was to estimate the distribution and causes of abortion in dairy herds across New Zealand during the 2001/2002 breeding season. A questionnaire survey was sent to all veterinary practices that were listed as m...

BACKGROUND The Swedish control program for salmonella includes restrictions and on-farm control measures when salmonella is detected in a herd. Required control measures are subsidised by the government. This provides an opportunity to study costs for on-farm salmonella control. The aim of this study was to describe the costs for on-farm salmonella control in Swedish cattle herds and to investi...

A high rate of on-farm cow mortality (i.e. unassisted death and euthanasia) is both a financial concern and an important animal welfare issue. The overall aim of this thesis was to evaluate the development of mortality in Swedish dairy herds and to identify characteristics associated with on-farm mortality at cow and herd levels. In paper I, two analyses were performed using data from the cattl...

Salmonella is one of the most serious foodborne pathogenic bacteria in the United States, causing an estimated 1.3 million human illnesses each year. Dairy cows can be reservoirs of foodborne pathogenic bacteria, including Salmonella spp.; it is estimated that from 27 to 31% of dairy herds across the United States are colonized by Salmonella. The present study was designed to examine the occurr...

Bovine rotaviruses isolated from beef and dairy herds in Argentina were serotyped by the immunoperoxidase focus reduction assay as previously described (G. Gerna, M. Battaglia, G. Milenesi, N. Passarani, E. Percivalle, and E. Cattaneo, Infect. Immun. 43:722-729, 1984). Three strains from beef herds were related to the UK and NCDV bovine rotavirus strains defined as serotype 6 (Y. Hoshino, R. G....

BACKGROUND: Cardiovascular system is a very importantorgan that plays a vital role in tissue function. In farm animals,the growth and high milk production depends on function ofcardiovascular system. OBJECTIVES: Cardiovascular health inhigh and low-yielding dairy cows was investigated. METHODS:Fifty 4-year-old high- yielding Holstein dairy cows and fifty 4-year-old low- yielding Holstein dairy ...

The National Johne’s Demonstration Herd Project (NJDDHP) in the United States was initiated to evaluate the long-term feasibility and effectiveness of management-related practices designed to control Johne’s disease on dairy and beef cattle operations. The NJDDHP began in 2003 and includes 62 dairy herds and 20 beef herds in 17 states. All herds began with culture-confirmed Mycobacterium avium ...