SYNCHRONIZATION OF ESTROUS CYCLE AND THE STUDY OF REPRODUCTIVE PERFORMANCE IN LOCAL PIGS

Abstract

Pig production now plays an important role in the economy of Singapore. There are normally two directions in improving the production of pigs. One is to control the growth and carcass quality through the study of nutrition, the other is through proper selection and management. Batch farrowi.ng is recognised as being of great advantage to pig producers. It enables piglings to be raised in batches according to age and breeds, and also reduces many problems in managements, housing, disease control and livestock improvement. Batch farrowing is possible if the time of mating of gilts and sows could be effectively synchronized according to the breeding schedule. Gerrits and Johnson (1964, 1965a, b), Gerrits et al (1966, 1968a, b), Baker (1967), Cummings (1967), Groves (1967), Nishikawa et al (1968) and Polge et al (1968) had successfully synchronized the estrous cycle of both sows and gilts by oral administration of ICI 33,828 compound (Aimax), and found no adverse effects on reproductive performance. It is therefore the purpose of the present study to find out if the compound could be used to synchronize the estrous cycle of pigs in local farms. The stages during the normal estrous cycle were also established by vaginal smear technique before synchronization. Garber and First (1969 c) have shown evidence that ICI 33, 828 compound (Aimax) blocks LH and FSH release, but not their synthesis. It is therefore the purpose of this experiment to find out if estrus in prepubertal and delayed pubertal gilts could be brought about by the compound. Production registry records of the local pigs are one of the main indicators for improving the breeding and management programmes. Therefore, an attempt was carried out to analyse the data from the farm records in order to find out the reproductive performance in different breeds of pigs.