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Effect of Reduced Energy Intake
on Organ and Gland Weights in Brangus Cows, by J.A.S. Chipepa and D.E.
Ray, Zambia Journal of Science & Technology, Vol.7, October 1984, Pg 22-30.
An experiment was conducted with Brangus cows to evaluate the effect of loss of
body weight and condition on gland and organ weights. The treatment groups were:
lactating intact (LI), lactating overiectomized (LO), nonlactating intact (NLI),
and nonlactating overiectomized (NLO). The study was carried out in two separate
blocks, each one consisting of 3 periods. During period 1 the cows were fed a
ration that supplied 90% or 80% of the National Research Council (NRC)
recommendation for Total Digestible Nutrients (TDN) in lactating and
nonlactating cows, respectively. This period lasted 170 days in block 1 and 130
days in block 2. During period 2 the TDN was reduced to 55% or 52% for lactating
and nonlactating cows, respectively. Period 2 lasted 100 days for cows in block
1 and 63 days for cows in block 2. At the beginning of period 3, TDN was further
reduced to 25% or 27% for the lactating and nonlactating cows, respectively. No
significant differences in the weight of the cows among the treatment groups
were found. All cows were, however, losing weight through the course of this
study. The nonlacting cows maintained higher body condition (P < .05) than
lactating cows from 31 days after ovariectomies were performed until the end of
The weights of the heart, adrenals, kidney, udder, and reproductive tracts were
not different amongst the treatment groups at slaughter. The weight of the
pituitary in lactating ovariectomized cows was significantly greater (P < .05)
than that of the nonlactating intact cows. There were no difference in the
weight of the left and right ovary in lactating and nonlactating intact cows.
Folicular fluid volume did not differ in the intact cows. When the organs were
expressed as a function of cow's weight, adrenals were significantly different
only between lactating oveariectomized and nonlactaing overiectomized cows.
(0.957 g/kg versus 0.040 g/kg; P < .05). Lactating cows had significantly lower
(P < .05) carcass lipid than nonlactating cows. Although the differences in fact
cover over the twelfth ribs were not significant, lactating cows both intact and
ovariectomized had much lower values than their nonlactating counterparts.
Percent protein and moisture were significantly higher (P < .05)in lactating
than in nonlactating cows. Loss in boy weight and condition in the present study
did not affect organ and gland weights preferentially.
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