Sm. Das et al., Effects of calf management and level of feed supplementation on milk yieldand calf growth of Zebu and crossbreed cattle in the semi-arid tropics, LIVEST PROD, 59(1), 1999, pp. 67-75
The study was conducted on 45 Zebu and 37 crossbred cows that calved in two
seasons, the wet and dry season. All cows were fed 2 kg of concentrate mix
ture daily for 40 days pre-partum in addition to grazing. At calving, cows
and their calves were randomly assigned to one of four groups: (1) HAR (n =
18) cows were fed a high level of concentrate supplement (4 kg/day) and ca
lves were artificially reared; (2) HRC (n = 24) cows were fed a high level
of concentrate supplement (4 kg/day) and restricted suckling of calves was
practiced; (3) LAR (n = 23) cows were fed a low level of concentrate supple
ment (2 kg/day) and calves were artificially reared and (4) LRC (n = 17) co
ws were fed a low level of concentrate supplement (2 kg/day) and restricted
suckling of calves was practiced. Calves in all of the groups were weaned
at six months of age. Feeding high or low levels of concentrate supplements
to cows was continued for 90 days postpartum, Five animals were excluded f
rom the study for various reasons and the results were derived from 77 cows
. Two calves died before weaning. Group LAR had the highest frequency (81.8
%) of cows with short lactation lengths ( < 200 days). Daily milk yield, la
ctation yield and lactation length were significantly affected by the treat
ments. Cows in group HAR had a mean lactation yield of 2386+/-141.77 kg, wh
ich was significantly higher than for cows in groups HRS (1539+/-116.42 kg)
, LAR (1161+/-120.84 kg) find LRS (778+/-131.48 kg). Total milk produced (l
actation yield + milk suckled by the calf) by HRS cows averaged 2346.7+/-10
1.07 kg, and did not differ (P < 0.05) from that of HAR cows, but was signi
ficantly higher than for cows in groups LAR and LRS. The interaction, breed
x group significantly influenced the daily milk yield and lactation yield.
The lactation length of cows in group HRS, of 290.3+/-11.51 days, was sign
ificantly longer than for cows in the other groups, i.e. HAR, LAR and LRS.
Cows calving in the wet and dry seasons did not differ in lactation yields,
but the lactation length of cows calving in the dry season was significant
ly longer than for cows calving in the wet season. Crossbred cows had highe
r daily milk yields and lactation yields than the Zebu cows (P < 0.05), whi
le lactation lengths of the two breeds did not differ significantly. Calf l
iveweight and average daily gain to three months of age were significantly
affected by group. Calves in group HRS had a significantly higher liveweigh
t, of 49.5+/-1.14 kg at three months of age, and a higher average daily gai
n, of 334.8+/-11.06 g, than calves in the other groups. Calves born in the
wet season had higher liveweights at three and six months of age than calve
s born in the dry season. Crossbred calves had significantly higher livewei
ghts at three and six months of age, and higher mean daily weight gain to t
hree months of age and up to weaning age than the Zebu calves. The performa
nce of the cows in the HRS group in terms of total milk production, longer
lactation length and the added advantage of the higher growth rate of calve
s than of those in the HAR, LAR and LRS groups shows that restricted suckli
ng coupled with a high level of feed supplementation is important for high
performance in Zebu and crossbred cattle. (C) 1999 Elsevier Science B.V. Al
l rights reserved.