EVALUATION OF HEAT TOLERANCE AND PERFORMANCE OF CROSSBRED DAIRY CATTLE IN CAUVERY DELTA REGION OF TAMIL NADU
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Date
2021
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Abstract
The aim of the study was to look into the current management practices of
crossbred dairy cattle among farmers in the Cauvery delta region of Tamil Nadu,
mainly Tiruchirappalli, Thanjavur, and parts of Pudukkottai districts. A pre-tested
interview schedule was used to collect information on existing management
practices and constraints from 90 randomly selected crossbred dairy farmers. In the
Cauvery Delta region, the majority of cross-bred dairy farmers (48.89 per cent)
were medium-aged and educated. Moreover, animal husbandry was either the
primary (25.56 per cent) or secondary (74.44 per cent) occupation of farmers.
The herd size of animal maintained by farmers were nearly identical in all
groups with large (above 10 animals) 35.56 per cent, small (1 to 5 animals) 34.44
per cent and medium (6 to 10 animals) 30.00 per cent. In this region, 42.22 per cent
of farmers had more than 20 years of experience, 38.89 per cent had less than 10
years of experience, and 18.89 per cent had 11 to 12 years of experience
respectively, in crossbred cattle rearing.
In this study region, the crossbred dairy cattle were housed in loose type of
housing with East - West orientation by 70 per cent of the farmers adjacent to their
homes. The commonly prevalent roofing pattern was gable type (54.45 per cent)
with galvanized iron sheet (33.33 per cent) as roofing material.
Semi-intensive system of rearing was widely practiced (66.67 per cent) in
this region with all farmers feeding concentrates ranging from 300 to 400 g (46.66
percent) to 401 to 500 g (45.56 per cent) on the basis of milk yield per animal per
day. Majority (85.55 per cent) of the farmers provided green fodder and almost all
the farmers provided dry fodder with most of them fed nearly 5 to 6 kg per day
(60.00 per cent) to their dairy cattle either from their own harvest or purchased.
Mineral mixture (64.40 per cent) was the most widely used feed supplement.
Artificial insemination (81.11 per cent) was the most widely used breeding
method. Regarding calf management practices in this region, colostrum feeding
(100 per cent), ligation of navel cord (53.33 per cent) and deworming (81.11 per
cent) were commonly followed. Vaccination (98.89 per cent), deworming (94.44
per cent) and isolation of sick animals (88.89 per cent) were habitually followed to
control diseases. Excellent milking practices like cleaning of animals, utensils and
hands (100 percent) were adopted.
The Temperature Humidity Index (THI), Black Globe Humidity Index
(BGHI) and Heat Load Index (HLT) values of thatched shed were 82.06 ± 0.49,
83.17 ± 0.64 and 87.32 ± 1.36, respectively, which were significantly low compared
to other roofing structures in farmer’s field.
The diverse impediments significantly faced by crossbred dairy cattle
farmers in this region were scarcity of feed resources, high feed costs, repeat
breeding, ignorance about selection and breeding and involvement and exploitation
by middlemen.
In this study region, the crossbred dairy cattle were housed in loose type of
housing with East - West orientation by 70 per cent of the farmers adjacent to their
homes. The commonly prevalent roofing pattern was gable type (54.45 per cent)
with galvanized iron sheet (33.33 per cent) as roofing material.
To evaluate the effect of heat stress on the performance of crossbred dairy
cattle for all the four seasons, the meteorological parameters inside the cattle shed
were recorded daily in the organized farm. Higher significant difference (P<0.01)
was observed for average feels like temperature between all four seasons but
A Highly significant difference (P<0.01) was observed in the evening after
exposure to sunlight for the physiological responses of rectal temperature, skin
temperature (rump and shoulder) and respiration rate for all the four seasons, but
pulse rate showed highly significant difference (P<0.01) between seasons except
winter and NEM.
Hematological values of RBC count and Hb in crossbred dairy cattle showed
highly significant difference (P<0.01) in the evening after exposure to sunlight
between winter and summer; winter and SWM respectively, whereas the PCV
values were highly significant (P<0.01) between winter and summer seasons.
Cortisol levels in the evening showed a highly significant difference
(P<0.01) between winter and summer; winter and SWM, while T3 levels showed a
highly significant difference (P<0.01) between winter and summer; winter and
SWM; NEM and summer respectively.
It was observed from the study, that a highly significant difference (P<0.01)
was observed for Iberia Heat Tolerance Test (HTC) and Benezra’s Coefficient of
Adaptability (BCA) values between four seasons but Dairy Search Index (DSI)
values were also highly significant (P<0.01) between seasons except NEM and
winter; SWM and summer respectively. The HTC value for crossbred dairy cattle
during summer (94.39 ± 0.28) was low and less heat tolerant, whereas the BCA and
DSI values for SWM (2.79 ± 0.02 and 1.073 ± 0.003 respectively) and summer
(2.88 ± 0.02 and 1.078 ± 0.002 respectively) showed deviation from adaptability.
average ambient temperature, wind speed, relative humidity and black globe
temperature showed higher significant difference (P<0.01) between seasons except
during South West Monsoon (SWM) and summer. The average THI value of the
cattle shed were highly significant (P<0.01) between four seasons whereas the
average BGHl and HLI values were highly significant (P<0.01) between seasons
except SWM and summer. The average THI value was within comfort zone during
winter (73.09 ± 0.21) whereas it exceeded during all other seasons. The average
BGHI values of the dairy cattle shed were comfortable for winter (75.47 ±0.18)
and North East Monsoon (NEM) (76.73 ± 0.15), whereas the HLI values were
comfortable only in winter (75.59 ± 1.13).
Highly significant difference was noticed in fat, SNF and protein content of
evening milk samples between winter and seasons of SWM and summer and
between NEM and summer. The average daily milk yield was highly significant
(P<0.01) between seasons and a higher yield was recorded in winter (6.80 ± 0.04).
THI, BGHI and HLI values were negatively conelated with daily milk yield. The
HTC values were positively correlated with daily milk yield, whereas the BCA and
DSI values were negatively correlated.
The ameliorative treatment groups (T?, T3 and T4) showed highly significant
(P<0.01) decrease in physiological responses when compared to control (Tj) in the
evening after exposure to sunlight in heat ameliorative study.
The HTC values of the ameliorative groups showed highly significant
(P<0.01) increase from control. Similarly, BCA and DSI values showed highly
significant (P<0.01) decrease in ameliorative groups from control.
The hematological values (RBC count, Hb, PCV and Platelet count) and
milk composition (SNF content and protein content of milk) of the ameliorative
group (T3) showed significant (P<0.05) increase in their values compared to control.
The daily milk yield was highly significant (P<0.01) between ameliorative groups
and control. Among the ameliorative treatment groups, the T3 group supplemented
with yeast Saccharomyces cerevisiae (2.5g per animal/ day) and splashing of water
had better performance level during summer.