Effect of Sex on the Body Weights of Pure Breed Sahiwal Calf under the High Humid Conditions of Assam

The demand for pure and organic food products are increasing day by day in the whole world. In a country where 60-70% of people depend directly or indirectly on the agricultural sector, India can increase its milk production of its indigenous cattle population to meet the growing demand. India holds the 2^nd position in agricultural production. Contribution of India to the global agricultural output accounts for 7.39%. According to the economic survey 2017-18, agricultural sector contributes 17-18% to the country’s Gross Domestic Product (GDP). One cannot separate the livestock sector from the agriculture, because a huge portion of income is generated from this sector. Therefore, implementing various policies to improve the livestock germplasm is of utmost importance. In this regard, the introduction of various milch breed of cattle has gained momentum. Amongst the various milch breeds found in India, Sahiwal is one of the highest producers with its origin from Sahiwal area in the Montgomery district of Punjab in Pakistan. According to Breed Survey, Deptartment of Animal Husbandry, Dairying and Fisheries, Government of India, 2013, the population of Sahiwal cattle in India is 10.92.459. Availability of this pure breed in the north-eastern part of India is very much finite. It is one of the main reasons to select Sahiwal as the breed of study for providing performance data to the field workers. In this study, body weights of calves were analyzed. The increasing body weight of animals at different age plays an important role to assess the dam’s health condition, their milking ability as well as an idea about the calves’ prenatal development processes. Measurement of newly born calf provides a clear picture to the producer, breeder and the farmers in judging their health along with their mother soon after their birth (Wakchaure, and Meena, 2010). Calf born with reduced size and weight provides an indication of illness and reduced production of the dam in future. The present study was conducted in order to conserve, further propagate and bring about genetic improvement of this outstanding Indian milch breed under the high humid conditions of North East India, in particular Assam. Very low and very high birth weight calves results increase incidence of death and calving difficulty in both the dam and in the calf (Johanson and Berger, 2003). Calves born with lower birth weight are associated with lack of vigor, their thermo regulatory mechanism shows reduced function, inability to fight against pathological agents and less ability to overcome different stresses, particularly the parturition stress (Holland, and Odde, 1992).

The present study was carried out in the Department of Animal Genetics and Breeding, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, India. Pure breed of Sahiwal calf was taken as the breed of study in our research programme. The university is maintaining a pure herd of Sahiwal cattle at the College campus since August, 2017. Data were collected from the Sahiwal cattle farm, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati for a period from August, 2017 to January, 2020 by utilizing a total of 25 numbers of Sahiwal calves born in the farm itself. This study has been approved by the Institutional Animal Ethics Committee. The particular herd was maintained with sufficient care and special concern was undertaken to avoid any discomfort in the farm. The cattle sheds were constructed within the farm complex in a scientific manner, having all the facilities for the comfort of the animals. Stall feeding and open grazing practices are done periodically. The particular herd was well pronounced for their good reproductive and mothering ability. They were also provided with scientific management and breeding practices.
 
Collection of data
 
Body weight of Sahiwal calves were recorded as per the following sequence:
·      At the day of birth
·      1^st month of age
·      2^nd month of age
·      3^rd month of age
·      4^th month of age
·      5^th month of age
·      6^th month of age
Body weights of the calves were recorded as monthly interval in the digital weighing balance during our experimental period. Before the process of loading in the platform, the digital meter was adjusted to zero in order to minimize the error and the same goes after unloading. Each value was noted and recorded in the unit of kilogram for the purpose of further analysis.
 
Statistical analysis
 
The Least Squares Analysis of Variance Technique of Harvey (1975) was used to analyze the data. To make pair wise comparison among the means showed by the sex effect, Duncan’s Multiple Range Test (DMRT) as modified by Kramer (1957) was used.

The body weights of Sahiwal calves from birth to six months of age were averaged out with the help of least squares means. The least squares means along with standard errors in the day of birth, 1^st month, 2^nd month, 3^rd month, 4^th month, 5^th month and 6^th months were 26.96±0.27 kg, 32.03±0.47 kg, 37.03±0.62 kg, 42.91±0.76 kg, 48.45±0.77 kg, 55.22 ± 0.77 kg and 62.08±0.88 kg respectively (Table 1). Month wise gains along with the overall body weight were plotted in a graph and results were compared thereafter as shown in Fig 1. Body weight at birth in case of crossbred calf was found relatively similar to our result as reported by Hiremath et al., (2007) that was 26.0±0.38 kg. They obtained a higher value for the calves of six month’s age (74.1±2.81 kg). Body weight at birth was found less for Sahiwal calf, 20.80±0.07 kg as reported by Manoj et al., (2012) that coincides with the result obtained by Wakchaure and Meena, (2010), which was 20.41±0.23 kg. Gandhi and Kumar, (2014) and Manoj et al., (2014) performed two separate works by taking Sahiwal as the breed of their choice; the resultant values at the day of birth were 20.59±0.27 kg and 20.54±0.079 kg and at six months of age were 82.29±2.64 kg and 81.48±0.659 kg respectively. In a comparison between Sahiwal and crossbreed calves, Dandapat et al., (2010) recorded relatively higher value for crossbred calf (26.8±0.63 kg) than that of Sahiwal calf (20.833±0.599 Kg). Khan et al., (1999) and Chandrakala and Sinniah, (2002) had done two separate studies in Sahiwal calves at birth and they recorded quite similar results; that were 21.4±2.5 kg and 21±2.5 kg respectively. Another report from Chakravarthi et al., (2017) revealed that body weight at 1 month, 3 month and 6 month of age were 34.25±5.27 kg, 34.75±4.97 kg and 46.25±5.57 kg respectively. Kayastha et al., (2008) recorded a much lower value for indigenous cattle of Assam; that was 14.667±0.150 kg. In case of Red Kandhari calves, overall least squares mean for body weight at 0-3 months of age and at 4-6 months of age were 51.65±0.62 kg and 114.15±1.09 kg respectively (Bainwad D.V.et_al2019). Again, Wagh et al., (2019) reported 31.24±0.62 kg body weights at 0-3 months of age for Gaolao calves of Maharashtra.
 

 
Effect of sex
 
Analysis of variance technique revealed that the factor sex had significant effect (<0.05) on the body weight of calves during the day of birth and at the 4^th month, but there was no any significant effect of sex in the 1^st, 2^nd 3^rd, 5^th and the 6^th months of age (Table 2). Body weight growths for male and female calf were calculated out separately. The least squares means for male calves were 27.54±0.39 kg, 32.71±0.68 kg, 38.30±0.89 kg, 44.43±1.10 kg, 50.27±1.10 kg, 56.53±1.11 kg and 63.16±1.27 kg from birth to six months of age respectively. On the other hand, least squares means for female calves were 26.38±0.37 kg, 31.35±0.66 kg, 35.77±0.85 kg, 41.39±1.06 kg, 46.62±1.06 kg, 53.91±1.07 kg, 60.99±1.22 kg from birth to six months of age respectively. The male calves were found significantly heavier than the female calves. Chakravarthi, et al., (2017) conducted a study on four Sahiwal cows and calves and revealed that the males were significantly heavier than females upto one year of age. He also observed that the variations in the growth rate are primarily due to the managemental practices and feeding schedule followed in different regions of the country. Better managemental practices and feeding schedule pointed out by Manoj, et al., (2012). Chandrakala and Sinniah, (2002) revealed that sex of calf had no significant effect on birth weight; it is primarily due to the poor managemental conditions of pregnant cows. Selvan et al., (2018) conducted a study and found that sex of calf had highly significant (P<0.01) influence on the birth weight of zebu and crossbred cattle. The male calves had higher birth weight compared to female calves. The mean body weights of male calves were found as 20.52±0.19 kg, 21.63±0.31 kg and 28.86±0.30 kg and female body weights were 19.31±0.19 kg, 20.18±0.29 kg and 27.71±0.30 kg in case of Sahiwal, Tharparkar and crossbred calves respectively. Manoj, et al., (2014) reported that the sex of calf had highly significant effect on birth weight of Sahiwal calves. They found that the average birth weight of male calves (22.27±0.07 kg) was 1.64 kg (7.95%) higher than female calves (20.63±0.07 kg). Study conducted in case of indigenous cattle of Assam revealed that sex of calf produces highly significant effect on birth weight (Kayastha, et al., 2008). Again, they found that the body weight of male calves (15.466 0.203 kg) was significantly heavier than that of the female calves (13.868±0.201 kg). Bainwad et al., (2019) reported that the least squares means of body weight for male calves at 0-3 months and 4-6 months of age were averaged 51.82±0.85 kg and 118.06±1.62 kg and in case of female calves, at 0-3 months of age and at 4-6 months of age were 51.47±0.85 kg and 110.24±1.29 kg respectively. The least squares analysis of variance has revealed non-significant effect of sex on body weight of Red Kandhari calves at 0-3 months of age but highly significant (P<0.01) effect of sex at 4-6 months of age. Wagh et al., (2019) revealed that least squares mean for body weight of Gaolao calves for male and female calves were 32.19±0.85 kg and 30.30±0.89 kg respectively. The least squares analysis of variance revealed non-significant effect of sex on body weight of Gaolao calves at 0-3 months of age.
 

From the above study, it was concluded that sex of the calf of the calf had significant effect on the growth weight of cattle. Implementation of better managemental practices and feeding schedule will lead to more improvement of the herd. This study was done outside the breeding tract of Sahiwal cattle. It was proved that in high humid conditions like north eastern parts of India, this milch breed can thrive well and can cope up against their natural habitat. Utilization of this information would be helpful for the producers and farmers to double their income which was one of the main aims of the government in increasing the economy of the nation.

The author is grateful to Dr. Purabi Kaushik, Major advisor for the constant help and guidance. Author will be ever grateful to Dr. R.N Goswami, for providing a helping hand to make the analysis of data successful. Lastly, author wishes to thank all the members as well as required facilities available in the farm.