The aim of this study was to evaluate the effect of inclusion of tannic acid on some performance traits and nutrient digestibility in Holstein dairy calves. A total of 20 seven days old Holstein calves were randomly assigned to 4 experimental treatments with 5 calves each. The treatments were as follows: 1) basal diet formulated to meet all nutritional requirement of calves according to NRC (20...

Fecal specimens were collected from 30 calves from birth to 24 months of age at a dairy farm in Maryland to determine the prevalence of Giardia duodenalis genotypes in cattle of different ages. Fecal samples were subjected to density gradient centrifugation to remove debris and concentrate cysts. Specimens were analyzed by immunofluorescence microscopy and polymerase chain reaction (PCR). All P...

The objective of this experiment was to investigate the therapeutic efficacy of a supplemental bovine serum protein blend fed to calves challenged with virulent coronavirus. Twelve Holstein bull calves (approximately 3 wk of age) were allocated by initial body weight to Control (n = 5) and treated (n = 7) groups. On d 0, all calves were orally challenged with 1 x 10(7) plaque-forming units of v...

Pathogenicity of Mycoplasma mycoides subsp. capri (Mmc) for calves with and without Trypanosoma congolense (Tc) infection was undertaken. Four calves were inoculated with Tc and two of them were challenged with Mmc, while one calf was inoculated with Mmc only; another calf was inoculated with sterile broth as control. No overt disease was found in the Mmc-infected calf. The two calves with dual...

A mating plan was designed to test the genetic hypothesis that atresia coli is inherited as an autosomal recessive at a single locus with two alleles. Matings between 8 putative carrier sires and 56 putative carrier dams resulted in 59 normal and 8 atresia coli calves, which was not different from the expected number of 8.1 affected calves. One case of atresia coli was observed among 628 calves...

The objective of this study was to evaluate the response of weaned calves to different feed additives within a preconditioning supplement. Specifically, alternatives to antibiotics and ionophores were evaluated to determine their effectiveness in improving calf performance and mitigating the stress response observed during the weaning process. Following stratification by bodyweight, sex, previo...

The objective of this study was to determine if deworming nursing calves prior to weaning would increase calf weaning weight. A total of 568 calves from three different locations were randomly assigned to either a deworming treatment (doramectin injectable) or control (no treatment) 90 d prior to weaning. Dewormed calves had greater body weight gain prior to weaning compared to control calves. ...

Soybean hulls (SBH) and soybean meal (SBM) were evaluated as potential supplements for preconditioning beef calves in Florida. Weaned calves were fed 4.76 lb/hd/d as fed of SBH or 1.40 lb/hd/d as fed of SBM for a 42-d preconditioning period. Calves fed SBH yielded higher preconditioning weight gains than calves supplemented with SBM (34.8 lb/ hd vs 22.3 lb/hd). An economic evaluation of precond...

A challenge experiment was performed to investigate whether administration of Mycobacterium avium subsp. paratuberculosis (MAP) via the respiratory route leads to MAP infection in calves. Eighteen calves from test negative dams were randomly allocated to four groups. Six calves were challenged with MAP nasally and six calves were challenged by transtracheal injection; three orally challenged ca...

Eight bull calves (four Holsteins and four Ayrshire calves with mean birth weight of 38.8 kg) were ruminally cannulated at 3 d of age and allocated to one of two weaning programs. All calves were fed colostrum for 3 d after birth and milk until weaning. Calves in the conventional-weaning program were fed a starter diet from 3 d of age and weaned at 6 wk of age. In the early-weaning program, cal...