Effect of Non-genetic Factors on Culling and Mortality Rate in Murrah Buffalo Males

| Sixteen years data (1997-2012) comprising of records on 1029 Murrah buffalo males born in NDRI herd were analysed to study culling and mortality rates. Data were classified into four periods viz., P-1 (1997-2000), P-2 (2001-2004), P-3 (2005-2008), P-4 (2009-2012) and four seasons of birth viz., S-1 (Dec-Mar), S-2 (Apr-Jun), S-3 ( Jul-Sep), S-4 (Oct-Nov); to study the disposal pattern of different age groups of buffalo male calves. Mortality rates in different age groups of 0-1, 1-2, 2-3, 3-6, 6-18, 18-36, 36-60 and above 60 months were 17.49, 5.99, 3.34, 5.42, 6.35, 2.59, 2.81 and 1.96 percent, respectively and corresponding culling rates for the age groups were 6.32, 9.95, 9.86, 14.69, 25.60, 39.81, 39.89 and 34.31 percent; respectively. Mortality rate was higher in young age groups (0-1 months, 1-2 months) whereas, culling rate was higher in six months and above age group. Overall disposal rate in eight age groups were 23.81, 15.94, 13.20, 20.10, 31.95, 42.39, 42.70 and 36.27 percent respectively. Effect of season and period of birth was statistically significant (p<0.01) for overall disposal rate in age groups of 0-1, 1-2, 2-3, 3-6. Higher overall disposal rate in male calves born in Dec-Mar and Jul-Sep could be due to higher mortality which could be attributed to exposure to inclement cold weather conditions in the former and parasitic infection in the latter season.


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inseminated with semen of proven bulls are therefore, raised for frozen semen production for subsequent inclusion in test mating.However, prior to reaching frozen semen production, a number of high genetic merit males are disposed of due to various reasons.Hence, knowledge of disposal pattern is very helpful in accurate planning and successful execution of genetic improvement programme.Therefore, there is a need to evaluate the disposal rate to assess the relevance of their use as monitoring criteria in herd-health schemes.
The rates of animal disposed from the herd due to season and period of birth were calculated by proportion using descriptive statistics.To study the differences in disposal rate, Chi-square value was calculated (Snedecor and Cochran, 1968).

RESULTS AND DISCUSSION
Overall disposal, mortality and culling rates of different age group of Murrah buffalo males are presented in table 1. Overall disposal rate of males from 0-1, 1-2, 2-3, 3-6, 6-18, 1.5 mo-3 yrs, 3 yrs-5 yrs and >5 yrs age group were 23.81, 15.94, 13.20, 20.10, 31.95, 42.39, 42.70 and 36.27 percent, respectively.Whereas mortality rates were 17. 49, 5.99, 3.34, 5.42, 6.35, 2.59, 2.81, 1.96 and culling rate 6.32, 9.95, 9.86, 14.69, 25.60, 39.81, 39.89, 39.31 & 34.31 percent, respectively.In younger age groups overall disposal was mainly due to mortality while in older age groups overall disposal was due to culling.According to Afzal et al. (1983) the mortality in buffalo calves was found to be 39.8% which is comparatively higher than our finding.Pradhan and Panda (1994) also reported that high mortality in Murrah buffalo calves occurred mainly during 0-3 months of age.Effect of season of birth was highly significant (P<0.01) on overall dis-posal up to 6 months age group whereas period of birth was highly significant (P<0.01) for 1-2, 2-3 6-18 month age groups and significant (P<0.05) for 0-1, 3-6 month age groups.Pandey et al. (2012) found that effect of season, period and sire was highly significant (P<0.01) on mortality rate, while for culling season effect was significant.Highest disposal rate in 18 mo-3 yrs and 3-5 years age groups was found because during this age animal comes into semen donation stage so more of disposal due to reproductive problems like libido problem, semen freezability.Disposal due to surplus was observed in these age groups which might be due to more number of bulls available than the requirement of the farm.At NDRI herd Chauhan (2007) conducted a study on Karan Fries males and found that important cause of disposal for male calves below 1.5 years of age was mortality and in case of above 1.5 years of age group, culling due to poor growth and poor semen quality were the main reasons.Based on 15 yrs data Mukhopadhyay et al. (2010) reported that subfertility problem is one of the major causes of disposal of breeding bulls which was almost one-third to half of the reserved stock disposed due to sub-optimal reproduction efficiency and poor libido was one of the important cause of subfertility among the Murrah buffalo males.
In P4 maximum culling and mortality was observed in 6-18 mo and 0-1 mo age group i.e. 15.15% and 28.46% while minimum culling and mortality estimated in 0-1 mo (0.41%) and 2-3 mo (4.97%) age groups.Overall disposal revealed a decreasing trend as per period advanced.The results indicated that management practices over the time were improved.
Effect of season and period was found to be statistically significant (P<0.01) for overall disposal rate in age groups of 0-1, 1-2, 2-3, 3-6 months.Higher overall disposal rate in age groups up to 2 months of age was observed for first and last periods which could be primarily due to higher mortality rates during those periods.For the age groups of 3-6 and 6-18 months, overall disposal rate was lower in last period which could be due to decline in culling rates over the years.Higher overall disposal rate in male calves born in Dec-Mar and Jul-Sep could be due to higher mortality which could be attributed to exposure to inclement cold weather conditions in winter season and parasitic infection in the latter season.So managemental intervention is important in winter months like bedding should be dry and soft, make some arrangement for prevention of direct cold air.The result of the study indicated that mortality rate was higher in young age group (up to 6 months), whereas culling rate was higher in older age group (above 18 months).Higher overall disposal rate in male calves born in Dec-Mar may be due to higher mortality due to inclement cold weather whereas high

Advances in Animal and Veterinary Sciences December 2014 | Volume 2 | Issue 12 | Page 659Table 1 :
Disposal rate of different age group of Murrah males

Table 2 :
Effect of season and periods of birth on disposal rate of Murrah buffalo males Figure in parentheses indicate percentage; * χ2(P<0.05),** χ2(P<0.01);Av.Anim. is availability of animals.