The effect of a maternal dietary yeast cell wall supplement during gestation on cow performance and calf growth and immunity
The objective of this study was to determine if feeding of yeast cell wall (YCW) to pregnant cows influences cow performance as well as postnatal calf growth and immunity. Multiparous cows were assigned by predicted calving date into either the control (C; n=24) or supplemented (Y; n=24) groups. The Y cows were fed 4 g of YCW in 230 g of ground corn top-dressed on 1.81 kg of corn gluten and soybean meal (4:1) from approximately 90 d prepartum through 28 d postpartum. Weight and body condition score (BCS) were taken at 28-d intervals prepartum and postpartum. Within 24 hr of parturition, the BW and BCS of cows and BW of calves were recorded, and blood samples from calves were obtained to determine white blood cell numbers. These procedures were repeated on d 14 and 28 postpartum, and continued at 28-d intervals through weaning. Weaning weights were adjusted to 180 d of age. Cows were observed for estrus twice daily starting d 28 postpartum through first estrus. Data were analyzed using the MIXED procedure in SAS. Yeast supplementation did not affect cow prepartum BW (P=0.39) or BCS (P=0.14), postpartum BW (P=0.97) or BCS (P=0.89), or the postpartum interval (P=0.98; C=56.2±3.3, Y=56.3±3.2 d). Calf weight was not different at birth; however, on d 14 and at weaning, C males tended to be heavier than Y group males as well as females from the C and Y groups (P=0.08, 0.07, respectively). At d 28 C males were heavier than Y males or females (P=0.02). There was a tendency for 180-d adjusted weaning weight to be heavier for C males than either Y males or C and Y females (P=0.0563). There was also a treatment by day interaction in which C calves were heavier than Y calves (P=0.01) and a calf sex by day interaction with males being heavier than females preweaning (P=0.01). Treatment did not affect the white blood cell profile of calves on d 0 or 28 as C and Y calves had similar percentages (P > 0.2) of lymphocytes, monocytes, segmented neutrophils, banded neutrophils and eosinophils. The C males demonstrated a greater growth rate than prenatally supplemented calves in the neonatal and preweaning periods. These data suggest that prenatal YCW supplementation to healthy mature cows in a low stress environment does not benefit cow or calf performance.
Keywords: yeast cell wall, calf performance, cow performance