THE INTERRELATION BETWEEN VARYING LEVELS OF PROTEIN AND ENERGY IN THE FOOD RATIONS FOR BOARS KEPT FOR BREEDING PURPOSES, THEIR SEXUAL BEHAVIOUR AND THE QUALITY OF THEIR SPERM

Milen Boychev, Yodan Marchev

Abstract: The experiment was carried out in the Agricultural Institute - Shumen, and involved 20 boars of the Danube White breed, each fed on daily rations of 2.3kg combined forage containing varying amounts of crude protein and metabolizable energy. The time was measured between entering the boar into the mating box, its mating with the dummy and the duration of ejaculation. The ejaculates were then measured in terms of amount (cm3), thickness (mln/cm3), рН, number of doses for insemination from one ejaculate, survival of spermatozoa after 24, 48 and 72 hours, and their dehydrogenase activity. The conclusion is that increasing the level of metabolizable energy from 11.50 MJ/kg to 13.60 MJ/kg notably affects the time for ejaculation (P<0.05). The time for ejaculation (P<0.05) is in medium positive correlation with the amount of ejaculates (r=0.284* and r=0.139). A negative interrelation is established between the time for ejaculation and the thickness of sperm (r= –0.129 for group I и r= –0.132 for group II ).

Keywords: boar; energy; libido; protein; sperm quality

Date published: 2023-03-07