Abstract :
The objective of this study was to examine the chemical and immunological quality of goat
colostrum following delivery. Twenty dairy goats of the Majorera breed were milked 1 h
postpartum and then every hour for 10 h after the first milking. Residual colostrum (RC)
was also obtained at the time of the first milking after i.v. injection of 2 I.U. of oxytocin.
Colostrum yield, approximate composition, SCC, IgG, IgM, IgA and chitotriosidase activity
were measured in milking colostrum (MC), RC, and colostrums in each hour sample.
A PROC MIXED procedure was performed and a Tukey’s test was done to determine the
statistical significance of differences in the composition of the colostrum fractions and the
colostrum obtained over time. At the first milking, MC and RC weighed 2506 and 237 g,
respectively. At 1 h and 10 h after the first milking, the colostrum yield was 174 and 120 g,
respectively, with a continuous drop in yield over the course of the experiment. A drop in
protein production was also seen over time. Colostrum protein percentages were 10.4 and
10.2 in MC and RC. Colostrum protein percentages at 1 and 10 h after first milking were 9.7%
and 4.5%, respectively. The percentage of colostrum fat increased 1 h after the first milking
and then decreased to 6.1% at 10 h after the first milking. The lactose colostrum percentage
displayed an increase during the experimental period. Colostrum SCC was not affected by
colostrum fractioning or time, with a range of 4.2–5.8 × 106 cells/mL. IgG, IgM, IgA levels
and chitotriosidase activity did not present differences between colostrum fractions at the
first milking but displayed a drastic drop in subsequent milkings. In sum, the chemical and
immunological quality of colostrum dropped quickly after the first milking, and thus goat
keepers need only recover the first milked colostrum when they rear goat kids separately
from dams.
