The objective of this study was to evaluate the effect of vaccination against GnRH on performance traits, pig behaviour and acute phase proteins. A total of 120 pigs (36 non-castrated males, NCM; 36 males to be vaccinated, IM; 24 castrated males, CM; and 24 females, FE) were controlled in groups of 12 in pens with feeding stations allowing the recording of individual feed intake. The two vaccinations (Improvac®) were applied at a mean age of 77 and 146 days. All pigs were individually weighed every 3 weeks from the mean ages of 74 to 176 days and backfat thickness (BT) and loinmuscle depth (LD) were also recorded ultrasonically. Twelve group-housed pigs for each treatment were video recorded during 2 consecutive days at weeks 9, 11, 20, 21, 23 and 25 of age to score the number of inactive or active pigs in each treatment group by scan sampling. Aggressive behaviour by the feeder and away from the feeder, and mounting behaviour was also scored by focal sampling. Blood samples from 12 NCM, 12 CM and 12 IM were taken to determine the concentration of circulating acute phase protein Pig-MAP at weeks 1, 2, 4, 11, 13, 21 and 25 of age. After slaughter, the number of skin lesions on the left half carcass was scored. IM presented overall a higher growth rate and daily feed intake compared to NCM (Pb 0.05), whereas their feed conversion ratios did not differ significantly. In comparison with CM, IM presented a better feed conversion ratio (Pb 0.05), since their overall daily weight gain did not differ significantly, but IM ate less. Final lean meat percentage of IM and CM was lower compared to that of NCM (Pb 0.05). Activity, mounting and aggressive behaviour of NCM was higher than in IM, CM and FE after the second vaccination. Pig-MAP concentrations were significantly elevated just after surgical castration and after both administrations of the vaccine (Pb 0.05), but concentrations subsequently decreased throughout time. Skin lesions of NCM were significantly higher compared to that of IM and FE (Pb 0.05). The effects of vaccination were especially remarkable after the second dose, when the higher feed intake and lower activity of IM compared to NCM might result in higher final body weight and more fat. Results from this study indicate that some welfare aspects such as a reduced aggression and mounting behaviour may be improved by vaccination against GnRH, together with productive benefits like adequate feed conversion ratio and daily weight gain.

The fine mapping of polymorphisms influencing cholesterol (CT), triglyceride (TG), and lipoprotein serum levels in human and mouse has provided a wealth of knowledge about the complex genetic architecture of these traits. The extension of these genetic analyses to pigs would be of utmost importance since they constitute a valuable biological and clinical model for the study of coronary artery disease and myocardial infarction. In the present work, we performed a whole genome scan for serum lipid traits in a half-sib Duroc pig population of 350 individuals. Phenotypic registers included total CT, TG, and low (LDL)-and high (HDL)-density lipoprotein serum concentrations at 45 and 190 days of age. This approach allowed us to identify two genomewide significant quantitative trait loci (QTL) for HDL-to-LDL ratio at 45 days (SSC6, 84 cM) and for TG at 190 days (SSC4, 23 cM) as well as a number of chromosomewide significant QTL. The comparison of QTL locations at 45 and 190 days revealed a notable lack of concordance at these two time points, suggesting that the effects of these QTL are age specific. Moreover, we have observed a considerable level of correspondence among the locations of the most significant porcine lipid QTL and those identified in humans. This finding might suggest that, in mammals, diverse polymorphisms located in a common set of genes are involved in the genetic variation of serum lipid levels.lipoproteins; lipid metabolism; candidate genes IDENTIFICATION of the genetic factors regulating the concentrations of serum lipoproteins has been a major goal in the prevention and treatment of atherosclerosis. A tremendous effort has been made in this direction by using approaches that combine whole genome scans with information generated by gene expression and bioinformatic analyses (76,81,82). In humans, Ͼ100 quantitative trait loci (QTL) influencing high (HDL)-and low (LDL)-density lipoprotein levels as well as triglyceride (TG) concentrations have been found (82). Moreover, the comparison of mouse and human genomic data has shown that LDL, HDL, and TG QTL display a striking positional concordance in these two mammalian species (80 -82).The inclusion of additional mammalian genomes in this human-mouse QTL comparative framework would yield great benefits in the search of genes influencing susceptibility to atherosclerosis. Pigs are an interesting experimental model to tackle this issue for several reasons. First, pigs have been used as a biomedical model of human diseases for decades, with a special impact on those related to myocardial infarction, cerebral ischemia, and atherosclerosis (44). Familial hypercholesterolemia has been reported in pigs, and, unlike other model species, affected individuals develop atherosclerotic lesions in the coronary vasculature that closely match those observed in humans, suggesting that atherosclerosis shares a common pathogenesis in both species (31). Moreover, the existence of a relevant amount of additive genetic variability for serum lipid traits in pigs has been demo...

13Boar taint is the off-odour or off flavour of cooked pork. Currently, the most common 14 method of controlling boar taint is surgical castration. However, immunocastration has 15 been used in some parts of the world as an alternative to surgical castration. The aim of 16 this study was to evaluate the sensory acceptability of immunocastrated pigs meat ( consumer's evaluation of meat from IM, CM, and FE. In contrast, EM meat presented a 23 higher percentage of dissatisfied scores and was significantly (P<0.05) less accepted 24 than meat from CM, IM and FE. Consumers' acceptability of EM meat was always 25 lower, independently of its androstenone levels. However meat with low levels of 26 androstenone was more accepted that meat with medium or high levels of this 27 substance. It can be concluded that immunocastration produced pork that was accepted 28 by the consumers, and was comparable to pork from CM or FE. 29 30

Because feed is the major cost to pork production, management practices and breeding strategies are aimed at optimizing feed intake. Knowledge about the shape of feed intake and feeding behavior curves may be of interest for optimization of lean meat production. This study investigated trends based on daily measurements of feeding behavior in 200 Duroc barrows, originating from 5 sires and 200 dams, during growth. Daily values were examined between 88 and 188 d of age. Furthermore, phenotypic correlations between feeding length and feeding rate, and feeding frequency, feed intake, residual feed intake, growth rate, and rate of fat deposition were investigated for a period between 95 and 175 d of age. No differences were observed between sires for parameter estimates of a curvilinear function fitted to data on feeding length as a function of age, but the effect of sire was significant (P < 0.01) for values at individual ages up to 132 d of age. Feeding rate (feed ingested for each minute spent eating) increased in a linear fashion with age (average R(2) = 0.80) and differently so for different sires (P < 0.05 for the intercept and P < 0.01 for the regression coefficient). Because the increase in BW is linear over this time period (average R(2) = 0.99), the results suggest that feeding rate increased with increased BW and is related to the physical capacity for feed intake. Results indicate that pigs that ate faster also ate more (r = 0.29, P < 0.001), grew faster (r = 0.40, P < 0.001), and grew fatter (r = 0.28, P < 0.001), but had no greater or lower residual feed intake (r = -0.01). The linear regression slope of feeding rate on age seemed inherent to the individual and was correlated with feed intake but not with residual feed intake. Feeding length may be selected for in order to regulate absolute feed intake at different stages of growth.

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