Impact of raising Improvac®-vaccinated boars on growth, carcass quality and meat quality compared to physical castrates under fi eld conditions

Abstract

Introduction Boar taint is related to sexual maturity and male hormones and is usually controlled by surgical castration. With growing focus on animal welfare, surgical castration without anesthesia has become controversial. Alternative approaches include immunization against gonadotropin releasing factor (GnRF)1, which disrupts the hypothalamic-pituitary-gonad axis, thereby temporarily suppressing testicular function and steroid synthesis. Our aim was to compare productivity, carcass quality and meat quality of pigs vaccinated against GnRF using Improvac against those of surgically castrated pigs under fi eld conditions. Materials and Methods The trial was conducted in a commercial farm in Lithuania. 402 cross-bred pigs were split into two groups. Pigs in group 1 (204) were castrated at 3 days of age. Pigs in group 2 (198) were vaccinated with Improvac at day 95 and day 140 of life. All pigs were fed the same farm-made diet depending on the growth phase. Animals were weighed in groups of 20-30 at weaning (d.28) entry to the fattening stage (d.60); fi rst vaccination (d.95), second vaccination (d.140) and on the day of slaughter (d.180) and daily weight gain (DWG) was calculated. Mortality was recorded and necropsies performed. Fat was measured using a Fat-o-Meater according to the routine slaughterhouse procedures. Samples of longissimus dorsi were tested to assess meat quality. Means, standard deviations and coeffi cients of variation were calculated for the variables assessed. The unpaired t-test (MS Excell 2003) was used to test diff erences between the mean values of groups. P<0.05 was used as the signifi cance level. Results Castrates were signifi cantly heavier (74.1kg v 66.5 kg [...].