Preparation of questionnaire and data collection: The questionnaire was prepared according to the objective of the investigation and was designed in a simple way so that the farmers could understand easily. The questionnaire included questions to collect information on age at puberty, oestrous cycle length, oestrous duration, prominent oestrous signs, gestation period, number of piglets born per sow, parity of sows, interval between farrowing and onset of oestrus and number of services required for each pregnancy. The investigator personally visited the farms of selected study area. Direct interview method was used for collection of information. Information given by pig farmers was recorded on questionnaire.
Study area, period and study population of pigs: Pig farms of Haluaghat, Dubhaura, Mymensingh Sadar and Muktagachha upazila of Mymensingh district were selected for the study during the period from December 2012 to May 2013. A total of 20 pig farms having 298 pigs (135 pigs from 14 farms of Haluaghat uapazila, 130 pigs from 1 farm of Dubhaura Upazila, 18 pigs from 2 farms of Mymensingh Sadar upazila and 15 pigs from 3 farms of Muktagacha upazila). Among total pigs, 60 were breedable females (sows), 27 were breedable males (boars) and 211 were piglets. The number of pigs per farm varied from 2 to 130.
Management of pigs: The sows were reared either traditionally, extensively, semi-intensively or intensively by the farmers. In extensively managed small holding farms, most sows were under grazing freely daily. All sows had free access to drinking water. There was no restriction of suckling by piglets. Weaning is occurred naturally in these sows. Boars and sows were kept together and natural mating occurred among them. They were kept in open houses made by bamboo. By day, sows were kept free and they took food from here and there. In semi-intensive system, floor of some houses was made of concrete and some were made of sand. Most of the houses of pigs were not cle an and the surrounding of house was not clean also. The houses of sows were located near the drain or garbage. Farmers are not careful of the general health condition of swine. Some farmers practiced deworming (12 farms out of 20) regularly but no vaccinations were in practice there. At night, they were kept in houses. Sows were fed with rice husk, rice polish, rice gruel and waste product of hotels. In traditional rearing system sows are tied by rope or chain with a tree or thumb and feed was supplied to th em under tied condition. Piglets are free range until matured. No extra care or management was done for them. But in intensive rearing system, matured and young pigs were housed separately and fed them separately. They were protected from extreme weather and extra care was taken for pregnant sows. Sometimes breeding boar was house separately.
Determination of reproductive parameters of sows: Age at puberty was determined by calculating intervals from birth to first detected oestrus of individual gilt and was expressed in days. Oestrous cycle length was determined by calculating intervals between two consecutive oestruses and was expressed in days. Oestrous period was determined by calculating intervals from the onset of oestrus to the end of oestrus and was expressed in hours. Prominent oestrus signs of sows were determined by observing behavioral and physical signs of gilts and sows by the farmers. Gestation length of sows was determined by calculating the interval between the date of last service and the date of parturition and was expressed in days. Number of piglets born per sow was determined by counting the numbers of live and dead fetuses delivered by individual sows. Parity of sows was determined by recording the number of parturition occurred by individual sows and farmers were interviewed to know this. Interval between farrowing and onset of oestrus in sows was determined by calculating by the interval between date of parturition and date of onset of oestrus and was expressed in days. Number of required services for each pregnancy was determined by interviewing the farmers and by calculating the number of services required for each pregnancy.
Statistical analysis: The collected data were entered into the Excel datasheet and descriptive statistics were performed. The values for age at puberty, oestrous cycle length, oestrous period, prominent oestrous signs, gestation length, number of piglets born per sow, interval between farrowing and onset of oestrus, number of services for each pregnancy were expressed as mean ± standard deviation.