INFLUENCE OF PROLACTIN ON UDDER DEVELOPMENT IN PREPUBERTAL SHEEP

Abstract

One of the main agricultural activities in Bosnia and Herzegovina is the production of milk, both from beef and sheep. According to the available data, the number of sheep in the world has exceeded one billion (1.08 billion), and in B&H it is slightly higher than one million (1,021,000 heads). About 8.3 million tons of sheep's milk is produced in the world. The structure and function of the mammary gland is of crucial importance for milk production. The development of the mammary gland is influenced by several factors. One of the most important is the action of hormones. A crucial role for the development of the mammary gland is played by prolactin, which simultaneously affects the initiation and maintenance of lactation. Based on the set experiments, exogenous application of prolactin, its influence on the development of the udder in prepubertal females and the histological picture of the udder in untreated and treated udders were established. Treatment with prolactin was carried out by intramuscular injections in a dose of 5 IU, three times for 60 days (every 20 days). One group (36) was treated in the period of early spring (April-May), and the other (36) in the period of early autumn (September-October). Female lambs were on average 250 days old (8.5 months) at the time of treatment. Sixty days after the treatment, the animals were sacrificed and the complete udders with ligaments were taken, which were then measured. The following measurements were taken: mass of the complete udder, mass of the udder without skin and ligaments, length of the udder, width of the udder and diagonal length. The results obtained during both seasons showed that prolactin influenced the development of the mammary gland in sheep.