Group housing of preweaned dairy calves is a growing practice in the United States. The objective of this practice is to increase the average daily gain of calves in a healthy and humane environment while reducing labor requirements. However, feeding protocols, commingling of calves, and occurrence of disease in different calf-housing systems may affect the prevalence of antimicrobial drug-resi...

Prophylactic and therapeutic antimicrobial use in food animals is questioned because of the potential for development of resistant bacteria and future inability to use some antimicrobials for human or animal disease. The objectives of this study were to determine the effect of raising preweaned dairy calves without antimicrobials in the milk and minimizing therapeutic antimicrobial treatment on...

Isolation, Molecular Identification, and Antibiotic Resistance Profile of Salmonella Typhimurium Isolated from Calves Fecal Samples Dairy Farms in Hamedan

The objectives of the current research were to determine the effect of weaning on fecal shedding of Salmonella and Escherichia coli O157:H7 in dairy calves and to examine cultured isolates (to include Enterococcus) for antimicrobial susceptibility. This research was conducted on one large commercial dairy (>3000 head) in the southwestern United States. Two collections were made, during the wint...

There is growing interest among the public in farm animal welfare and a need for methods to assess animal welfare on farm. A survey on calf rearing practices that might affect dairy calf welfare was performed via a 1-h interview on 115 dairy farms (mean +/- SD: herd size=52.5+/-20.9 cows; milk production=8,697+/-1,153L) distributed throughout the province of Quebec. Despite frequent recommendat...

The prevalence of Cryptosporidium in calves younger than 10 weeks was estimated in a cross-sectional epidemiological study on 100 dairy (n=499) and 50 beef (n=333) farms in East Flanders (Belgium), using a previously evaluated immunofluorescence assay (Merifluor). The calf prevalence was 37% (95% Probability Interval (PI): 7-70%) in dairy calves and 12% (95% PI: 1-30%) in beef calves. To elucid...

continued on page 2 Manuel Chamorro, DVM Clinical Instructor College of Veterinary Medicine The bovine fetus has a type of placentation that does not permit contact between maternal and fetal blood and therefore does not permit passive transfer of immunoglobulins (Ig) from the mother to her fetus. The bovine calf is born agammaglobulinemic and depends on the intake of an adequate amount of mate...

The decline of dairy cattle fertility worldwide remains a major concern, with conception rates to first service commonly below 40%. The length and severity of negative energy balance postpartum are unfavorably correlated with fertility, suggesting that the length and severity of negative energy balance and fertility are linked via several hormones or metabolites. These compounds therefore have ...

Male Holstein calves (n = 120) purchased from local dairy farms were fed one of three calf milk replacers for 42 d. Experimental milk replacers were formulated to contain whey protein concentrate (WPC) as the primary protein source or WPC plus 5% spray-dried bovine plasma (SDBP) or spray-dried porcine plasma (SDPP). The SDPP was heated to remove heat-insoluble materials and provide products wit...

To observe the effects of supplemental dietary d-α-tocopherol in relation to dietary energy on growth and immune status in dairy calves, 32 newborn Holstein bull calves were assigned to 1 of 4 treatments for 5 wk in a 2 × 2 factorial, randomized complete block, split-plot design. Calves received moderate growth (MG) or low growth (LG) all-milk dietary treatments, formulated to support daily gai...