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Subject: Livestock Production and Management × Author: Das, Venus × Start date: 2022 × Type: Thesis ×
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    ThesisItemOpen Access
    Amelioration of heat stress through certain managemental interventions in lactating dairy cows
    (College of Veterinary Science, Assam Agricultural University, Khanapara Campus, 2023) Das, Venus; Hussain, Jakir
    The present experiment was executed in the Instructional Livestock Farm (Cattle) and Sahiwal Cattle Farm under in the Livestock Farm Complex, College of Veterinary Science, Assam Agricultural University, Khanapara,Guwahati-22 to observe the heat stress amelioration capacity of body cooling and bypass fat feeding during summer season (1St May to 31st August, 2022) in lactating dairy cows. A total of twenty four (12 Holstein-Friesian crossbred and 12 pure Sahiwal) lactating cows were divided into three groups with eight animals in each group with similar parity, stage of lactation and average daily milk production and with equal number of each breeds. The experimental animals were offered feed twice daily individually @ 4 percent of body weight on DM basis to meet up the optimum nutritional demand (NRC, 2001). Out of total DM 1/3rd was given standard concentrate feed (CP: 18% & TDN: 68.00%) prepared in the farm and 2/3rd was given roughages. Out of total roughage 1/3rd was given as paddy straw and 2/3 mixed green fodders such as Para (Brachiaria mutica), Napier (Pennisetum purpureum) and Guinea (Panicum maximum) grasses in equal parts. In the treatment group bypass fat was fed along with concentrate mixture @ 100 g in the morning and 100 g in the afternoon daily. The experiment was followed by a 7 days of digestibility trial. The average daily milk yield for T1, T2 and T3 group was 5.94±0.09, 8.26±0.12 and 9.58±0.20 kg, respectively and for Holstein-Friesian crossbred and Sahiwal cow, it was 8.57±0.23 and 7.37±0.13 kg, respectively. The average daily milk yield was significantly (p<0.01) higher in T2 and T3 group than the T1 group. The average fat, protein, SNF, lactose, ash, specific gravity and freezing point depression of milk in T1, T2 and T3 group was 3.07±0.11, 3.62±0.13 and 4.31±0.20; 3.46±0.02, 3.53±0.02 and 3.59±0.02; 9.26±0.04, 9.34±0.04 and 9.34±0.04; 5.38±0.03, 5.41±0.03 and 5.48±0.02; 0.75±0.01, 0.78±0.01 and 0.79±0.00; 1.0348±0.0001, 1.0349±0.0002 and 1.0352±0.00 and - 0.63, - 0.64 and - 0.63 percent, respectively and for Holstein-Friesian crossbred and Sahiwal cow, it was 3.74±0.11 and 3.58±0.14; 3.53±0.02 and 3.53±0.0; 8.06±0.19 and 9.3±0.03; 5.42±0.02 and 5.42±0.02; 0.77±0.00 and 0.76±0.00; 1.0348±0.001 and 1.0351±0.0001 and - 0.63and - 0.64 percent, respectively. The analysis of variance showed that there was highly significant (p<0.01) effect of treatment on the average fat, protein, ash and non-significant (p>0.05) effect on SNF, lactose, specific gravity and freezing point depression. The average fat, protein and ash content (%) was significantly (p<0.01) increased in T2 and T3 groups. The average daily dry matter intake (DMI), dry matter intake per 100 kg body weight and feed conversion efficiency (FCE) for T1, T2 and T3 groups was 11.93±0.21, 14.66±0.19 and 15.42±0.22 kg; 2.43±0.03, 2.98±0.02 and 3.10±0.03 percent and 0.50±0.01,0.51±0.01 and 0.51±0.01, respectively. The average daily DMI, DMI per 100 kg body weight and FCE of Holstein-Friesian crossbred and Sahiwal cow was 15.40±0.19 and 12.61±0.16 kg; 2.76±0.03 and 2.91±0.03 percent and 0.51±0.00 and 0.49±0.01, respectively. There was (p<0.01) significant increase in DMI in T2 and T3 groups compared to T1 group. The overall average Temperature Humidity Index (THI) was 78.01±0.65, 74.89±0.39, 76.26±0.39, 76.26±0.39, 80.7±0.61, 85.04±0.64, 82.80±0.53 and 79.17±0.22 for 1st fort night (FN), 2nd FN, 3rd FN, 4th FN, 5th FN, 6th FN, 7th FN and 8th FN, respectively. The average THI value for ILF(C) was 78.14±0.97, 74.99±0.56, 76.26±0.56, 77.69±0.70, 80.90±0.93, 85.25±0.96, 82.93±0.77 and 79.52±0.28 and For Sahiwal cattle farm, it was 77.87±0.90, 74.79±0.56, 76.26±0.56, 76.26±0.56, 80.5±0.81, 84.83±0.88, 82.66±0.74 and 78.82±0.33 during 1st FN, 2nd FN, 3rd FN, 4th FN, 5th FN, 6th ii FN, 7th FN and 8th FN. There was significantly (p<0.05) highest THI was found during 6th FN. The average respiration rate, pulse rate, rectal temperature and rumination time in T1, T2 and T3 groups was 26.84±0.54, 26.22±0.39 and 26.22±0.39 per min; 80.33±2.02, 67.52±1.31, 65.17±1.30 per min; 102.1±0.17, 101.4±0.10 and 100.69±0.08 ºF and 405.7±3.30, 425.59±4.45 and 438.88±4.45 min/day, respectively and for Holstein-Friesian crossbred and Sahiwal cows, it was 27.00±0.31 and 25.85±0.41per min; 74.44±1.45 and 68.11±1.41per min; 101.38±0.11 and 101.48±0.12 ºF and 422.92±3.33 and 423.85±3.21 min/day, respectively. There was highly significant (p<0.01) decrease in pulse rate, rectal temperature and increase in rumination time in T2 and T3 groups than the T1 group. But respiration rate was not affected by treatment in the present study. The average blood albumin, globulin and A: G ratio in T1, T2 and T3 groups was 5.28±0.21, 7.36±0.27 and 8.47±0.48 g/dl; 5.36±0.21, 6.91±0.32 and 7.97b±0.33g/dl and 1.01 ±0.03, 1.19±0.07 and 1.09±0.05, respectively and for Holstein-Friesian crossbred and Sahiwal, it was 6.56±0.29 and 7.51±0.32 g/dl, 6.35±0.25 and 7.13±0.26 g/dl and 1.12±0.04 and 1.07±0.04, respectively. There was highly significant (p<0.01) increase in blood albumin and globulin content in T2 and T3 group compared to T1 group in the present study. The average superoxide dismutase (SOD) level of plasma for T1, T2 and T3 groups was 8.06±0.10, 7.48±0.13 and 7.27±0.22 unit/mg of protein, respectively and for Holstein-Friesian crossbred and Sahiwal, it was was 7.69±0.15 and 7.52±0.11 unit/mg of protein, respectively. In the present study, it was found that there was significant (p<0.05) reduction in superoxide dismutase level of blood in T2 and T3 group compared to T1 group. The overall mean digestibility coefficient of DM, OM, CP, EE, CF and NFE in T1, T2 and T3 group was 67.05±0.15, 68.26±0.16 and 68.48±0.15; 68.46±0.17, 65.11±0.24 and 68.88±0.15; 64.89±0.24, 65.11±0.24 and 64.70±0.28; 53.69±1.19, 53.57±0.76 and 56.61±0.39; 59.67±0.20, 59.94±0.24 and 60.04±0.21 and 73.74±0.25, 74.74±0.25 and 76.71±0.15 percent, respectively and for Holstein-Friesian crossbred and Sahiwal cows, it was 68.10±0.14 and 67.76±0.17; 68.61±0.12 and 68.47±0.14; 65.01±0.13 and 64.79±0.26; 56.27±0.39 and 52.98±0.87; 60.10±0.18 and 59.67±0.17 and 75.02±0.25 and 75.11±0.27 percent, respectively. The analysis of variance showed non-significant (p>0.05) effect of treatment, breed and fortnight on digestibility coefficient of DM, OM, CP, CF and NFE. But in case of EE, there was highly significant (p<0.01) effect of treatment and breed on digestibility coefficient of EE. There was highly significant (p<0.01) effect of treatment and breed on the average daily cost of feeding and cost of feeding per kg milk yield. The mean cost of feeding and cost of feeding per kg milk yield for T1, T2 and T3 group was Rs. 212.27±3.70, 262.37±2.82 and 302.25±3.31 and Rs. 36.13±0.78, 31.43±0.27 and 32.17±0.58, respectively. Though the total cost of feeding for T3 group was found to be significantly (p<0.01) higher due to feeding of bypass fat, but cost of feeding per kg milk yield was significantly (p<0.01) lower in T2 and T3 group compared to T1 because of higher milk production. In respect of breed, the daily cost of feeding and cost of feeding per kg milk yield in HF crossbred was significantly higher than pure Sahiwal cows. The present experiment validated that heat stress can be ameliorated significantly by body cooling and feeding bypass fat during summer season for improvement of milk production and maximize the income from rearing of dairy cattle.