Document Type : Review Article
1 Lecturer of Payam Noor university, Faculty of Agriculture,Qom, Iran
2 Associate Professor of Azad University, Saveh Branch, Saveh, Iran
3 Lecturer of Payam Noor university, Tehran, Iran
The reproductive performance of a dairy herd has a significant effect on the profitability of that herd. Common measures of reproductive performance are days to first service, days to conception, calving interval, services per conception, conception rate, estrus detection rate, and pregnancy rate. Most cow operations would benefit economically by reducing the number of operational days, decreasing culling rates due to non-pregnant females, and shortening their calving interval. Several factors influence reproductive performance, but none require more visual attention than heat or estrus detection
Aroeria J A D, da Silva H M, Fontes L R and Sampaio I B M. (1977) Age at first calving, length of reproductive life and life expectancy in Zebu cows. Arquivos da Escola de Veterinaria, Universidade Federal de Minas Gerais 29: 301-309 (Animal Breeding Abstracts 46: 32-72).
Bastidas P. Troconiz J. Verde O and Silva O. (1984) Effect of restricted suckling on ovarian activity and uterine involution in Brahman cows. Theriogenology 21: 525-532.
Basu S B. Bhatnagar D S and Taneja V K. (1983) Genetic and phenotypic parameters of lifetime traits in Tharparkar cows. Indian Journal of Dairy Science 36: 207-210.
Bazan O. Munoz H. Deaton O W and Vohnout K. (1976) Reproductive performance of beef cattle in Costa Rica. Memoria, Asociacion Latinoamericana de Produccion Animal 11: 54 (Animal Breeding Abstracts 46: 1-254).
Bazer F W. (1973) A twenty-year summary of heterotic effects on reproduction in Florida cattle. In: M Koger, T J Cunha and A C Warnick (eds), Crossbreeding beef cattle Series 2. University of Florida Press, Gainsville, Florida. pp. 128-134.
Cruz V O. Koger M, Warnick A C and Frankie D E. (1976) Heritability of reproductive characters in Brahman cattle. Memoria, Asociacion Latinoamericana de Produccion Animal 11 25-26 (Animal Breeding Abstracts 46: 1264).
Dennis J P and Thiongane A I. (1978) Effect of intensive feeding on reproductive performance in female Gobra Zebu at the CRZ, Dehra. Revue d'Elevage et de Medicine Veterinaries des Pays Tropicaux 31: 85-90.
Duarte F A M, Valle A, Lobo R B and Bezerra L. (1983) Phenotype and genetic study in reproductive and production characters in the Pitanguieras breed. 2. Calving interval. Agronomia Tropical (Maracay, Venezuela) 30: 325-334 (Animal Breeding Abstracts 53: 1281).
Mahadevan P. Galukande E B and Black J C. (1962) A genetic study of the Sahiwal grading-up scheme in Kenya. Animal Production 4: 337-342.
Malik B S and Ghei G C. 1977. A note on some production characteristics of Gir cattle. Indian Journal of Animal Sciences 47: 587.
McDowell R E. (1971) Feasibility of commercial dairying with cattle indigenous to the tropics. Cornell international Agricultural Development Bulletin No. 21. Cornell University, Ithaca, New York, USA. 22 pp.
Singh R P and Raut K C. (1980) Studies on performance characteristics in cattle maintained under village conditions. Indian Journal of Animal Sciences 50: 619-623.
Wellington K E, Mahadevan P and Roache K L. (1970) Production characteristics of the Jamaica Hope breed of dairy cattle. Journal of Agricultural Science 74: 463 468.