References

Alvarez-Rodriguez, J. and A. Sanz, 2009. Physiological and behavioural responses of cows from two beef breeds submitted to different suckling strategies. Applied Anim. Behav. Sci., 120: 39-48.

Boettcher, P.J. and B.M.A.O. Perera, 2007. Improving the Reproductive Management of Dairy Cattle Subjected to Artificial Insemination: A Summary. International Atomic Energy Agency, Vienna, Austria, ISBN: 92-0-114806-2, pp: 1-7.

Bridges, G.A., G.E. Portillo, J.W. de Araujo, W.W. Thatcher and J.V. Yelich, 2005. Efficacy of either a single or split treatment of PGF2α after a 14 day melengestrol acetate treatment to synchronize estrus and induce luteolysis in Bos indicus × Bos taurus heifers. Theriogenology, 64: 344-362.
Direct Link  |  

Briggs, H.M. and D.M. Briggs, 1980. Modern Breeds of Livestock. 4th Edn., Macmillan Publishing Co., New York, USA.

Buddenberg, B.J., C.J. Brown, H.P. Peterson and A.H. Brown, 1989. Factors influencing pregnancy rate and calving date in four breeds of beef cows on an Ozark mountain range. Anim. Reprod. Sci., 18: 243-252.

DVS, 2011. Malaysia: Self-sufficiency in livestock products (%), 2000-2010. Department of Veterinary Services Malaysia. http://www.dvs.gov.my/c/document_library/get_file?uuid=d41d4a2a-ab2b-44d2-9f97-228767acd357&groupId=28711

Dobbins, C.A., D.R. Eborn, D.E. Tenhouse, R.M. Breiner, S.K. Johnson, T.T. Marston and J.S. Stevenson, 2009. Insemination timing affects pregnancy rates in beef cows treated with CO-Synch protocol including an intravaginal progesterone insert. Theriogenology, 72: 1009-1016.
PubMed  |  

Eversole, D.E., M.F. Browne, J.B. Hall and R.E. Dietz, 2009. Body Condition Scoring Beef Cows. Virginia Cooperative Extension, Blacksburg, Virginia, pp: 400-795.

Galina, C.S. and A. Orihuela, 2007. The detection of estrus in cattle raised under tropical conditions: What we know and what we need to know. Horm Behav., 52: 32-38.

Gungor, C., M. Ulubilir, M. Saler and S.G. Karakok, 2009. The comparison of two different seasons oestrus synchronization results with fixed-time AI protocols. J. Anim. Vet. Adv., 8: 373-378.
Direct Link  |  

Kasimanickam, R., M.L. Day, J.S. Rudolph, J.B. Hall and W.D. Whittier, 2009. Two doses of prostaglandin improve pregnancy rates to timed-AI in a 5-day progesterone-based synchronization protocol in beef cows. Theriogenology, 71: 762-767.
Direct Link  |  

Krininger, III C.E., J. Block, Y.M. Al-Katanani, R.M. Rivera, C.C. Chase Jr. and P.J. Hansen, 2003. Differences between Brahman and Holstein cows in response to estrus synchronization, superovulation and resistance of embryos to heat shock. Anim. Reprod. Sci., 78: 13-24.
CrossRef  |  PubMed  |  Direct Link  |  

Lyimo, Z.C., M. Nielen, W. Ouweltjes, T.A.M. Kruip and F.J.C.M. van Eerdenburg, 2000. Relationship among estradiol, cortisol and intensity of estrous behavior in dairy cattle. Theriogenology, 53: 1783-1795.
CrossRef  |  Direct Link  |  

Neglia, G., B. Gasparrini, R. di Palo, C. de Rosa, L. Zicarelli and G. Campanile, 2003. Comparison of pregnancy rates with two estrus synchronization protocols in Italian mediterranean buffalo cows. Theriogenology, 60: 125-133.
Direct Link  |  

Panandam, J.M., H.H. Abdelwahid, A. Majidi and Y.W. Kit, 2004. Genetic characterisation of indigenous Kedah Kelantan cattle and its crossbred breed types. Mol. Biol., 3: 56-58.
Direct Link  |  

Portillo, G.E., G.A. Bridges, J.W. de Araujo, M.V. Shaw, F.N. Schrick, W.W. Thatcher and J.V. Yelich, 2008. Response to GnRH on day 6 of the estrous cycle is diminished as the percentage of bos indicus breeding increases in angus, brangus and brahman angus heifers. Anim. Reprod. Sci., 103: 38-51.
PubMed  |  

Roelofs, J., F. Lopez-Gatius, R.H.F. Hunter, F.J.C.M. van Eerdenburg and C. Hanzen, 2010. When is a cow in estrus? Clinical and practical aspects. Theriogenology, 74: 327-344.
CrossRef  |  Direct Link  |  

Roelofs, J.B., 2005. When to inseminate the cow? Insemination, ovulation and fertilization of the dairy cattle. Ph.D. Thesis, Wageningen University, Wageningen, The Netherland.

Roelofs, J.B., E.G. Bouwman, S.J. Dieleman, F.J.C.M. van Eerdenburg, L.M.T.E. Kaal-Lansbergen, N.M. Soede and B. Kemp, 2004. Influence of repeated rectal ultrasound examinations on hormone profiles and behaviour around oestrus and ovulation in dairy cattle. Theriogenology, 62: 1337-1352.
PubMed  |  

Rosby, R., 2007. Early weaning beef calves. Vet. Clin. N. Am-Food A, 23: 29-40.

Sa-Filho, O.G., C.C. Dias, G.C. Lamb and J.L.M. Vasconcelos, 2010. Progesterone-based estrous synchronization protocols in non-suckled and suckled primiparous Bos indicus beef cows. Anim. Reproduc. Sci., 119: 9-16.
CrossRef  |  

Saumande, J. and P. Humblot, 2005. The variability in the interval between estrus and ovulation in cattle and its determinants. Anim. Reprod. Sci., 85: 171-182.
PubMed  |  

Sharif, Z.A. and W. Mohamed, 2005. Beef production for Malaysian entrepreneurs. Malaysian Agricultural Research and Development Institute (MARDI), Kuala Lumpur.

Sivarajasingam, S. and A.R. Kumar, 1993. Comparative performance of Malaysian, Australian and New Zealand F1 Friesian crossbreds. Livestock Prod. Sci., 36: 299-310.
CrossRef  |  

Smith, O.B. and B.S. Somade, 1994. Nutrition reproduction interractions in farm animals. International foundation seminar on animal production, Niamey, Niger, pp: 1-33.

Van Eerdenburg, F.J.C.M., D. Karthaus, M.A.M. Taverne, I. Mercis and O. Szenci, 2002. The relationship between estrous behavioral score and time of ovulation in dairy cattle. J. Dairy Sci., 85: 1150-1156.
Direct Link  |  

Verduzco, A., C.S. Galina, I. Rubio and M. Maquivar, 2006. Average response to estrus and timing of ovulation in Bos indicus cattle synchronized alternatively with a synthetic progestagen. J. Anim. Vet. Adv., 5: 924-929.
Direct Link  |  

Voh, A.A., A. Larbi, S.A.S. Olorunju, K. Agyemang, B.D. Abiola and T.O. Williams, 2004. Fertility of ndama and bunaji cattle to artificial insemination following oestrus synchronization with PRID and PGF_2α, in the hot humid zone of Nigeria. Trop. Anim. Health Prod., 36: 499-511.
CrossRef  |  Direct Link  |  

Warr, S., G. Rodriguez and J. Penm, 2008. Changing food consumption and imports in Malaysia. Opportunities for Australian agricultural exports (Australian Bureau of Agricultural and Resource Economics ABARE research report) Canberra, Australia, pp:1-29.

Weems, C.W., Y.S. Weems and R.D. Randel, 2006. Prostaglandins and reproduction in female farm animals. Vet. J., 171: 206-228.
Direct Link  |  

Yavas, Y. and J.S. Walton, 2000. Postpartum acyclicity in suckled beef cows: A review. Theriogenology, 54: 25-55.
CrossRef  |  PubMed  |  Direct Link  |  

Yelich, J.V., H.S. Mauck, M.D. Holland and K.G. Odde, 1995. Synchronization of estrus in suckled postpartum beef cows with melengestrol acetate and PGF_2α. Theriogenology, 43: 389-400.