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The objective of this study was to evaluate the long-term effect of a gonadotropin-releasing hormone (GnRH) vaccine, Improvac (Pfizer Ltd.), on the levels of GnRH antibodies, testosterone, estrone sulphate (E1S) and androstenone, as well as skatole and indole in male pigs. Additionally, the long-term effect of immunocastration on social and sexual behaviour was studied. Male pigs were assigned to two treatment groups: a treatment group given two doses of Improvac (n=12) and a control group of entire male pigs (n=12). The pigs were kept either 16 or 22 weeks after vaccination. Blood samples were collected five or six times; prior to both first and second vaccination, then three or four times during the 16 or 22 week period after second vaccination. Immunocastration significantly reduced levels of testosterone and E1S in plasma, and levels of androstenone in fat (P

This study aimed to compare different production systems, i.e., the combined effect of outdoor and indoor rearing of pigs and organic diets fed ad libitum or restrictively. Furthermore, the suitability of two breed crosses for outdoor rearing was studied. The effects on performance, carcass and technological quality traits were investigated. During two years, 240 pigs of Duroc x Large White (D*LW) and Swedish Landrace x Large White (L*LW) were allocated to three production systems: 1) Pigs kept outdoors, fed an organic diluted diet (20% alfalfa roughage) ad libitum; 2) Pigs kept outdoors, strategically fed a diluted organic diet up to a live weight of approximately 80 kg and thereafter an undiluted organic diet ad libitum; 3) Pigs kept indoors, fed an undiluted organic diet restrictively. For outdoor pigs, strategic feeding increased daily weight gain and backfat thickness, compared with feeding a diluted diet throughout (p≤0.01). L*LW pigs in both outdoor systems grew slower than in the indoor s...

The aim of our study was to investigate the effect of rearing system (mixed or single-sex) on performance and carcass quality of entire male and female pigs slaughtered at around 90 or 115 kg live weight. We also studied the combined effect of live weight and dietary supplement of raw potato starch (RPS) on technological meat quality for both sexes, and boar taint compounds in entire male pigs. Furthermore, we investigated pre-slaughter routines (pen-wise or mixing with unfamiliar pigs) and sexual maturity. A total of 408 growing/finishing pigs were included in this two-year study. Performance did not differ significantly between entire male and female pigs irrespective of rearing system, except for daily weight gain in the interval from 90 kg to slaughter. Mixed pigs had significantly higher daily weight gain in this interval than single-sex pigs. Entire male pigs had higher carcass lean meat content than female pigs (1.6 percentage units). Technological meat quality differed only slightly betwe...

The aim of this project was to study the effects of feeding system (dry or wet feeding with whey), dietary lysine level and pre-slaughter routines on technological meat quality in entire male, female and castrated male pigs, which were carriers or non-carriers of the RN − allele. The feeding system only affected the yield of processed meat, resulting in lower Napole yield (87.5% vs 89.4%) for meat of whey fed pigs. Further, lower dietary lysine levels resulted in higher drip loss of the meat compared with high dietary levels (5.3% vs 4.8%). Mixing of unfamiliar pigs prior to slaughter led to meat with lower internal reflectance values (28.3 vs 32.2) and glucose+G-6-P concentrations of the meat juice (46.3 vs 49.7 μmol/ml) compared with pen-wise slaughtering. In comparison with non-carriers, RN − carriers had significantly lower ultimate pH, shear force values and water-holding capacity. Mixing of non-carrier pigs prior to slaughter gave higher Napole yield compared with those handled pen-wise. Females had...

The effects of various environmental factors on sexual maturation of entire males were studied and the relationships between sexual maturation, weight of genital organs, production traits and backfat androstenone and skatole levels were investigated. The material comprised 550 crossbred entire male and 550 female pigs. All were fed a restricted dry or wet (whey or water) diet containing 0.85, 0.95 or 1.05% lysine. Entire males and females were raised in either single-sex or mixed groups. Feed was withheld in half of the pens for approximately 26 h before slaughter. The pigs were slaughtered at a live weight of 107 kg. Most of the entire males were classified as mature or well developed. Environmental factors did not affect sperm maturation. Epididymal weights for males raised together with females were heavier than for those raised in single-sex groups. Weights of genital organs were negatively (but weakly) correlated to the proportion of lean meat in the carcass. Withholding feed before slaughter resulte...