1. ANON, 1984. Dairy herd fertility Ref Book 259. London, HMSO
2. Bourchier, C.P., Garnsworthy, P.C., Hutchinson, J.M., Benton, T.A., 1987. The relationship between milk yield, body condition and reproductive performance in high yielding dairy cows (Abstr). Animal Production 44,460.
3. Cavestany, D., Corea, E., Silva, D., Meikle, A., 2003. Dairy cattle reproduction in tropics. Breed differences and metabolic profiles. In IAEA. Regional coordination meeting, Asuncion, Paraguay, 21st – 26th July.
4. Chamberlain, A.T., Wilkinson, J.M., 1996. Feeding the dairy cow. Chalcombe publications, UK, pp 151.
5. CLINPRO INTERNATIONAL CO. LLC., 2005. Progesterone Enzyme immunoassay test kit. No EH-511. Handbook.