Studies on replacement rate, Productive herd life, longevity,selective value and their components in different Indian and crossbred cattle-A review
Authors:   Department of Animal Genetics and Breeding, College of Veterinary and Animal Sciences, G.B.PantUniversityofAgricultureandTechnology, Pantnagar- 263 145, (U.S. Nagar), Uttarakhand India., Singh C.V. , kant Shashi , Dangi Manita 
Published: August 2024

The prevalence of abnormal births varied across various cattle breeds, with estimates ranging from 3.14 percent in Sahiwal cattle to 14.28 percent in crossbred cattle. The average sex ratio of 44.15%, (female calf) and 57.42% (male calf). The mean mortality rate in female calves from birth to age at first calving ranged between 13.70% inFrieswal (and 45.60 in crossbred cattle. The mortality rate during the first month of life varied among different breeds of calves and ranged from 4.22% to 16.92% in various breeds. During the age range of 1-3 months ranged from from2.3% to to12.90%, in the group of 3-6 months age mortality was found as 1.34% to 7.06%, in the group of 6-12 months age was found to be 0.81% to 5.06% and, from 12 months to age at first calving (AFC) ranged from 3.00% to 4.3% in different breeds calves. The mean culling rate in female calves from birth to age at first calving ranged between 3.72% and 31.05%. The replacement rate basis on female calves varied from 48.40% in Hariana cattle to 74.72% in Frieswal cattle. The effects of the calving period on abnormal calving have been observed-significant in various studies. However, other studies have also observed significant effects of the calving period on the occurrence rate of abnormal calving. Non-significant effects of the season were found in different studies. However, other studies have reported significant effects of the season. Heritability estimates for abnormal birth, sex ratio, female calf mortality, female calf culling, replacement rate from total female calf basis, and replacement rate from total calf based were reported to be very low. Productive herd life (PHL) ranged from3.06±0.09 years in Karan Fries cattle to 6.43±0.21 years in Sahiwal x Jersey crossbred cattle. The range of longevity is from 3.06±0.09 years in Karan Friesto to 8.76±0.28 years in the Sahiwal breed. The number of calves produced per cow was reported to be 2.91±0.07 in Frieswal’ 3.07±0.91 in Karan Fries 4.09±0.25 calves produced per cow in Sahiwal x Jersey crossbred cattle and 5.20±0.16 in Haryana. The maximum average of total alive calves born ranged from 2.71±0.15 in Frieswal cattle to 4.9±0.15 in Hariana cattle. The total number of female calves per cow ranged from 1.23±0.04 to 2.38±0.15. The number of replacement daughters per cow was observed from 0.74±0.05 to 1.61±0.11. The heritability estimates for productive herd life, longevity, total calves produced per cow, total calves produced per cow, total alive calves born, Selective value, and lactation-specific survival rate, for survivorship or stay-ability were observed from very low to high in different studies. It was found that around 1/4 of the total females left the herd after completing their first lactation. The percentage of cows in the herd was estimated and one-third of the total herd consisted of first-time calvers. A meager percentage (about 1.94%) of females in the herd were of 10th or more lactations. The anticipated herd life during the first parity was 1.47 lactations to 3.52 lactations, with a decreasing trend as the lactation number increased. The mean age of cows in the herd varied across cattle breeds from 2.54 lactations to 4.49 lactations. The average age of cows lost from the herd varied among the different breeds from 2.91 to 4.68 lactations. The mean loss rate per cow per lactation was from 0.21 lactations to 0.52 lactations. The replacement index in other studies was observed at 0.84 over 34 years and 1.4 over 20 years.