AMELIORATION OF HEAT STRESS WITH MODIFIED MICROCLIMATE IN LACTATING DAIRY CATTLE
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Date
2022
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KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, NANDINAGAR, BIDAR - 585401
Abstract
An experiment was conducted to compare the effectiveness of different heat stress
alleviating methods for lactating dairy cattle. Twelve lactating dairy were selected and
grouped into three treatments with four animals each group. The treatments vizT1 as
control, T2 (micro sprinklers) and T3 (wet gunny bags). The daily variation of min & max
environmental temperature and relative humidity were recorded both inside and outside
the shed, whereas 18.7 and 31.5 °C & 36.4 and 79.2 per cent inside the shed respectively
and outside the shed was 20.2 and 32.1°C & 41.7 and 84.0 per cent respectively. The
chemical compositions of feed were estimated and dry matter intake was showed nonsignificant
difference among treatment groups. The effect of heat stress or raise in
ambient temperature on physiological parameters viz., rectal temperature and pulse rate
was non-significant, whereas the respiration rate was found significant (P<0.005) among
the groups. Milk yield (kg/d) was significant between T1 and T2 (P<0.013) & T2 and T3
(P<0.043) and non-significant between T1 and T3. Similarly for milk fat % showed
significant difference (P<0.001) between T1 and T3 & T2 and T3 (P<0.001), but it was
non-significant between T1 and T2 groups. The SNF%, protein %, lactose % and CLR
showed non-significant difference among treatments groups. The fat yield (g/d) showed
significant (P<0.05) difference among all the groups. The protein and lactose yields (g/d)
were found to be non-significant. Fortnightly body weight changes (kg) showed nonsignificance
among the treatment groups. The serum cortisol (μg/dl), sodium (mEq/L)
and potassium (mEq/L) levels estimated on 0th, 30th and 60th day showed non-significant
difference. Hence the mild heat stress may not alter performance of dairy cows
significantly. Therefore, necessary modification of microclimate for rearing lactating
dairy cows is needed.