In the spring of 2013, a survey of California (CA) dairies was performed to characterize management practices related to bovine respiratory disease in preweaned calves, compare these practices across geographic regions of the state, and determine the principal components that explain the variability in management between herds. The questionnaire consisted of 53 questions divided into 6 sections...

Bovine viral diarrhea virus 1 (BVDV-1) subtype b was isolated from premature Holstein calves from a dairy herd that experienced an outbreak of premature births, late-term abortions, brachygnathism, growth retardation, malformations of the brain and cranium, and rare extracranial skeletal malformations in calves born to first-calf heifers. Experimental inoculation of 3 colostrum-deprived calves ...

A dairy herd including approximately 50 milking cows and 40 heifers and calves was investigated. This herd was detected with high prevalence of calves persistently infected (PI) with bovine viral diarrhea virus (BVDV). Nine PI animals including a milking cow and 8 newborn calves were detected in the herd within 4 months. Prevalence of PI animals in this herd was estimated 7.0% which was very hi...

Blindness attributed to vitamin A deficiency afflicted 47 out of 197, and 15 out of 29 new-born dairy calves on 2 farms. Other clinical signs included doming of the forehead, thickening of the carpal joints, incoordination and weakness. Gross lesions in 8 of the calves examined consisted in hydrocephalus and thickened occipital and sphenoid bones. In 4 of these calves the optic nerves were cons...

The aim of this experiment was to better describe early behavioral responses of calves to illness to help improve early detection. We examined the behavior of calves after injections of very low doses of bacterial lipopolysaccharide (LPS). Fifteen dairy calves of 2 ages (3 and 20 wk), housed in individual pens and fed milk and concentrates with free access to hay and water, were injected i.v. w...

The study evaluated possible transmission of Mycoplasma bovis from sand bedding to naive dairy calves. Screening of a closed herd showed 99% probability that the herd was free of mycoplasma in calves. Neonatal calves (n = 12) from the herd were blocked by weight and height and randomly assigned as controls (n = 6) bedded with quarry sand, or exposed (n = 6) bedded with M. bovis-positive bedding...

iv General Preface v Acknowledgements vi List of Tables xi List of Figures xiii List of Abbreviations xiv List of Publications xv Chapter one: Introduction 1 Chapter two: Neonatal calf diarrhoea: a literature overview 4 2.1. The principles of rearing of newborn dairy calves, with particular reference to the situation in New Zealand 4 2.2. The economic impact of neonatal calf diarrhoea 8 2.3. Ae...

Weaning of dairy calves is an early life husbandry management practice which involves the changeover from a liquid to a solid feed based diet. The objectives of the study were to use RNA-seq technology to examine the effect of (i) breed and (ii) gradual weaning, on the whole blood mRNA transcriptome of artificially reared Holstein-Friesian and Jersey calves. The calves were gradually weaned ove...

Sex-sorted semen can increase the profitability of dairy cattle by producing offspring of the desired sex. The objective of the present study was to compare conception rate, stillbirth, calving difficulty and sex ratios from sexed and conventional semen in a commercial dairy herd in Isfahan province, Iran. Data were collected from April 2009 until December 2015 on 13,343 inseminations in 8,011 ...