EFFECT OF DRAFT WORK ON PERFORMANCE AND METABOLISM OF CROSSBRED COWS .1. EFFECT OF WORK AND DIET ON BODY-WEIGHT CHANGE, BODY CONDITION, LACTATION AND PRODUCTIVITY
T. Gemeda et al., EFFECT OF DRAFT WORK ON PERFORMANCE AND METABOLISM OF CROSSBRED COWS .1. EFFECT OF WORK AND DIET ON BODY-WEIGHT CHANGE, BODY CONDITION, LACTATION AND PRODUCTIVITY, Animal Science, 60, 1995, pp. 361-367
Forty pregnant F-1 crossbred dairy cows (20 Friesian X Boran and 20 Si
mmental X Boran) were stratified in a 2 X 2 diet X work factorial expe
riment (not working-not supplemented, NWNS; not working-supplemented,
NWS; working-not supplemented, WNS; and working-supplemented, WS). Wor
king cows pulled sledges 100 days/year (pull = 350 to 450 N, 4 h/day,
4 days/week). Work output of supplemented and non-supplemented cows te
as similar over 1 and 2 years. Over all 3 years, dry-matter intake rel
ative to metabolic body size (g/kg M(0.75)) was greater for working, c
ompared with non-working cows. Body-weight changes and body condition
score were similar for working and non-working cows. Non-supplemented
cows lost weight throughout the first 2-year period, while supplemente
d cows tended to maintain or gain body weight over 1 and 3 years. Over
2 years, supplementation of working cows proportionately reduced live
-weight loss by 0.73 and doubled the number of conceptions and parturi
tions. Days in milk, milk, milk fat and protein yields were similar fo
r working and non-working cows, but were greater for supplemented, com
pared with non-supplemented, cows. Total conceptions and calves born i
n all 3 years tended to be greater for supplemented and non-working co
mpared with non-supplemented and working cows. A productivity index (P
I) that took into account food intake was calculated. The PI for suppl
emented cows over 2 years was greater than that for non-supplemented c
ows. Meanwhile the PI was similar for working and non-working cows ove
r all periods considered. A similar PI for working and non-working cow
s under supplementation indicates potential of on-farm adoption of a c
ow traction technology that includes improved food production and feed
ing strategies.