No abstract

ABSTRACT. The effects of a maternal vaccine against newborn calf diarrhea associated with group A bovine rotavirus (BRV), bovine coronavirus (BCV), bovine parvovirus and K99 Escherichia coli (E.coli) were examined on a beef cow-calf herd. After vaccination, serum or colostrum antibody titers to BRV, BCV and E. coli K99 in the vaccinated cows were significantly higher than those in unvaccinated control cows. Serum antibody titers to BRV, BCV and E. coli K99 in calves from the vaccinated cows were also significantly higher than those in calves from the control cows for 3-4 weeks after birth. These results suggested that the immunization of cows with the maternal vaccine enhanced the passive immunity levels in calves against BRV, BCV and K99 E. coli. -KEY WORDS: bovine coronavirus, bovine rotavirus, K99 Escherichia coli.J. Vet. Med. Sci. 59(11): 1023-1025, 1997 the first vaccination, the second booster injection was given in the same manner. The remaining 48 cows served as unvaccinated controls. The calves from the vaccinated and control cows were observed for clinical signs once daily. Serum samples were collected from the vaccinated cows at vaccination, at calving and post-calving days 2, 7 and 28, and from the control cows at times corresponding to sampling in the vaccinated cows. Colostrum and milk samples were collected from all the cows on the day of calving and post-calving days 2, 7 and 28. Serum and feces were taken from all the calves on days 2, 7, 21 and 28 after birth. Feces were also obtained when these calves developed diarrhea. The fecal suspensions were examined for enteric viruses by electron microscopy [2], and group A BRV was also detected by a latex agglutination test (Rotalex; Orion Diagnosis, Espoo, Finland). Virus-neutralizing antibody titers to NCDV (G6) and KK3 (G10) strains of group A BRV in serum and milk samples were determined by a fluorescence focus neutralizing (FFN) test with MA104 cells as described previously [9]. The virus-neutralizing antibody titers to the Mebus strain of BCV and the BF-15 strain of BPV were determined by CPE inhibition tests with HRT-18 cells and BT cells, respectively [15,19]. E. coli K99 antibody titers were determined by a passive hemagglutination test [8]. Statistical analysis of the data was performed using the Student's t-test and the χ 2 test.Abortions and other adverse reactions were not observed in the 48 vaccinated pregnant cows. At the first vaccination, there were no differences in serum antibody titers to BRV, BCV, BPV and E. coli K99 between the vaccinated and control cows. At the second vaccination, serum antibody titers to both G serotypes of BRV, BCV and E. coli K99 in the vaccinated cows increased and were higher than those of controls (P<0.05) ( Table 1). Colostrum antibody titers to both serotypes of BRV and E. coli K99 in the vaccinated cows were higher than those of control cows (P<0.05). For 3-4 weeks after birth, the calves from the vaccinated cows

Three pregnant cows were inoculated intramuscularly with inactivated vaccine to bovine rotavirus (BRV) serotype 1 (BRV-1) and serotype 2 (BRV-2). Serum neutralizing antibody (NA) titers against both serotypes increased significantly after immunization. NA titers of colostrum obtained from immunized cows against BRV-1 and BRV-2 were 29286 and 38109, respectively, which were significantly higher than those from non-immunized control cows. Nine and 6 colostrum deprived calves were orally challenged with BRV-1 and BRV-2, respectively, and monitored for clinical manifestation and viral shedding. Five calves of them, 3 with BRV-1 and 2 with BRV-2, received 2 l of milk replacer supplemented with 10% immune colostrum 2 hr before challenge and twice daily for the first 5 days after challenge. Other 10 calves, 6 with BRV-1 and 4 with BRV-2, were fed only milk replacer as controls. All control calves developed severe diarrhea and shed a large amount of BRV in feces, beginning from 24 to 48 hr after challenge inoculation. On the contrary, all calves but one fed colostrum supplement remained clinically healthy after challenge, and BRV was not detected in their feces during feeding immune colostrum. The possibility that continuous feeding of immune colostrum is capable of preventing newborn calves from diarrhea associated with BRV and viral shedding was suggested.

ABSTRACT. Effects of recombinant bovine granulocyte-macrophage colony-stimulating factor (rboGM-CSF) on bactericidal activity of bovine peripheral blood neutrophils in vitro and in vivo were studied. In in vitro experiment, bovine blood neutrophils were cultured for 9 hr in media containing 0.005, 0.05 or 0.5 µg/ml of rboGM-CSF. Neutrophils treated with rboGM-CSF showed significantly higher luminol-dependent chemiluminescence (LDCL) than control cells. In in vivo experiment, neutrophils isolated from cows injected 5.0 µg/ kg of rboGM-CSF showed significantly higher Nitrobluetetrazolium (NBT) reduction value than that from control cows 24 hr post injection. Total leukocyte counts of cows injected rboGM-CSF sharply decreased 6 hr post injection and recovered to normal level 2 days post injection. Body temperature of these cows rose 6 hr post injection and back to normal level at 24 hr post injection. It was suggested that rboGM-CSF enhanced bactericidal activity of bovine neutrophils both in vitro and in vivo.-KEY WORDS: bactericidal activity, neutrophil, recombinant bovine GM-CSF.

Six ruminally cannulated Wagyu (Japanese Black) steers (average initial bodyweight (BW) 387 ± 29 kg) were used in a split‐plot design experiment, comprising a 3 × 3 Latin square design (whole plot) and a randomized block design (subplot). The whole plot treatments were three different feeding levels of supplemental diet, fed at 0.2, 0.4 and 0.6% of BW, on a dry matter (DM) basis. Subplot treatments were two different supplemental diets: a potato pulp silage‐based diet (PPS) and a grain‐based diet (GRAIN). Chopped, medium‐quality cool‐season grass hay (predominately Timothy, Phleum pratense L) was fed daily at 0.7% BW (on a DM basis) as the basal diet. Each period consisted of 21 d, which included 11 d of adaptation to the diets and 10 d of the collection period. Chromium oxide was used as an indigestible marker. In situ forage degradation was measured using the nylon bag technique. The dry matter intake increased (linear; P < 0.01) as the feeding level increased and was not affected by the diet. Digestibility was not affected by any treatments. The GRAIN diet tended to decrease the rate of in situ forage degradation as the feeding level increased, but this trend was not found in the steers fed the PPS diet. Steers fed the GRAIN diet had a lower (P < 0.1) ruminal pH compared with steers fed the PPS diet. Ruminal pH was not significantly affected by feeding level; however, it was numerically higher for steers supplemented at 0.2% per BW than that for the steers supplemented above 0.4% per BW due probably to the higher starch intake. The total volatile fatty acids concentration numerically increased as the feeding level increased and was not affected by the diet. Increasing the feeding level decreased (linear, P < 0.01) the proportion of acetate. Neither diet nor the feeding level had any effects on the proportion of ruminal propionate. The results suggested that, for steers fed the PPS diet, there are not adverse effects on forage digestion in the rumen that occur as the feeding level is increased.