Reasons for postlactation anestrous periods occurrence in primipara sows
1988
Varga, F. ("Agroinstitut", Sombor (Yugoslavia)) | Trajkovic, B. | Gerhart, P. | Kovacevic, R. | Zigic, B. | Vasiljevic, Z. | Pujin, D.
In order to find causes of postlactation anestrous periods in primipara sows, we investigated the influence of the age at the time of the first mating, the duration of the first lactation, the number of sucking piglets and the influence of the duration of the season on the duration on the interval of weaning, - the first estrus occurence and weaning - conception. The results seem to indicate that these parameters by primipara sows are very variable within all these observed characteristics. The effect of conception during the warmer period of the year is reduced and the frequency of the return to service increased. No differences have been found with regard to the rate of body mass losses during lactation between primipara and older sows. The range of estradiol 17 beta and progesterone level in 15 tested primipara sows before, during and 20 days after estrus shows a high rate of coincidence with the physiological state of the animals, having estrus occurrence before the 6th day and deviations from the physiological values of the animals with prolonged estrus and anestric animals. In sacrificed anestric animals there has been found cystic degeneration of ovarian parenchyma with present carriers Streptoccocus species and Staphyloccocus epidermidis.
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