BACKGROUND: Dairy cows undergo physiological changes during pregnancy and lactation and cardiovascular system may alter during these periods. OBJECTIVES: Understanding the physiological effects of production periods of dairy cows on heart electrical activities can aid to better monitoring the cardiovascular system in these animals. METHODS: Five multiparous Holstein dairy cows were studied from...

OBJECTIVE To examine the effects of Rhodobacter sphaeroides (R. sphaeroides) supplementation as a direct-fed microbial (DFM) on rumen fermentation in dairy cows and on coenzyme Q10 (CoQ10) transition into milk, an in vitro rumen simulation batch culture and an in vivo dairy cow experiment were conducted. METHODS The characteristics of in vitro ruminal fermentation were investigated using rume...

Introduction In modern dairy cattle operations, antimicrobials are administered for both therapeutic and prophylactic purposes. Most antimicrobials are used therapeutically but some antimicrobials are used to prevent disease in healthy animals during periods of increased susceptibility. Mastitis is one of the most frequent infectious diseases in dairy cattle and accounts for most of the doses o...

More than a decade of observations of dairy operations in Hawai‘i suggested that there were more black cows in the local dairy herds than white cows. Hence, the objective of the study was to investigate if hair coat color affected productive life of Holstein cows in the sub-tropics. Two large herds within 2,000 meters of each other in the Waianae Coast district were used. Lactating cows were cl...

14 15 In this paper the implementation of a tool was considered, based on Machine Learning (ML) techniques to improve 16 the detection of subclinical mastitis in dairy herds. The analysed population included 71 dairy farms in Asturias 17 (Northern Spain) and a total of 2,407 lactating cows. Four sources of information were available: a) a questionnaire 18 survey describing facilities, milking r...

An adequate and clean artificial insemination (AI) technique is recommended to improve reproductive outcomes in dairy cattle. The objective of this study was to evaluate the effectiveness of using protective plastic sheaths (PS) to minimize contamination of the AI catheter (AIC) on pregnancies per AI (PAI) in lactating dairy cattle. Lactating cows housed in freestall barns on a commercial dairy...

A cross-sectional study was conducted to determine the prevalence of sub-clinical and clinical mastitis and the associated factors in cows from selected smallholder dairy farms in Zimbabwe. Physical examinations were conducted on all lactating cows for evidence of signs of clinical mastitis. Composite milk samples were collected from all lactating cows for bacterial culture and somatic cell cou...

A feeding trial utilizing lactating dairy cows was conducted to compare Eastern gamagrass (Tripsacum dactyloides) and alfalfa hay. Response criteria included feed intake, weight change, and yield and composition of milk. Dry matter intake and milk yield of cows fed alfalfa hay exceeded that of those fed gamagrass hay. There was no significant difference in milk composition, and average weight c...

Methane emission factors are lacking from different livestock species in various production states fed varying diets. The objectives of the present study were to measure effects of physiological state, silage type, and supplemental NDF on DMI, DM digestibility (DMD), and methane emissions of lactating and dry dairy cows using two 4 × 4 Latin squares (5-wk periods) with four lactating (114 DIM ±...

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...