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The objective of this research was to determine the effect of group size on pig performance. A field study was carried out during 15 months. The building had 52 pens in total, which housed grower pigs to 35-38 kg body weight. During the first 8 months the average number of animals was 726. During the time of most significant decrease of performance in months 9 and 10 the average number went up to 751 animals. A reduction in total feed intake was observed during months 9, 10 and 11 and the average consumption of compound feed per animal and day dropped to 1.68, 1.32 and 1.09 kg. Consequently the weight gain decreased to 615, 535 and 505 g, respectively. The example showed the negative influence of overstocking of grower pigs on the essential performance indicators, such as weight gain, compound feed consumption per feeding day and feed conversion. The number of animals in pens should be decided on the basis of stocking density which influence positively performance. The size of the lying area for this particular age group and this particular building should be between 0.48 and 0.51 sq m per animal.
The aim of this study was to evaluate the effect of genetically-modified (GM) insect-resistant corn (MON 810) and glyphosate-tolerant GM soybean meal (Roundup Ready, MON 40-30-2), used as the main dietary components for broilers, on the performance parameters, results of slaughter analysis, and the chemical composition of the breast muscles. In a 42-d floor pen experiment, Ross 308 broilers were fed corn-soybean meal diets. In the experiment, a randomised complete block design was used with 4 dietary treatments. Each treatment was divided into 4 replicates (pens) of 40 birds. All the experimental diets met the requirements of broilers; they were all isonitrogenous and isoenergetic, and contained non-modified corn and soybean meal (group I), non-modified corn and GM soybean (group II), GM corn and non-modified soybean meal (group III), or GM corn and GM soybean meal (group IV), respectively. The nutrient composition of Bt corn and its non-modified isogenic counterpart (parental line) revealed no major differences. The final live weight, average daily weight gain, feed intake, feed conversion (feed:gain ratio), and mortality rate did not differ statistically across the dietary treatments. No statistical differences (P>0.05) were also found in the results of slaughter analysis (carcass yield, meat yield, abdominal fat pad, and relative weight of the liver, gizzard, and spleen) and chemical composition of the breast muscles. It was concluded that insect-resistant GM corn (MON 810) and soybean meal produced from glyphosate-tolerant GM soybean (Roundup Ready) are nutritionally equivalent to conventional feeds and can be used as components of broiler diets with no adverse effect on performance indices.
The purpose of the study was to evaluate with BLUP the effectiveness of breeding work performed in a commercial farm of laying hens where the selection index approach was applied. Production results of two (maternal M55 and paternal V44) nucleus strains regarded nine generations (1994-2002). Considered were body weight at the age of 18 weeks (BW), age (days) at first egg (MAT), number of eggs laid during first 15 weeks (IL), mean egg weight at week 10 of laying (EW), number of eggs laid during 44 weeks (L44) and hatchability (HA). Mean inbreeding coefficient of inbred birds amounted to 1.7 and 2.2%, in M55 and V44, respectively. Estimates of h2 (REML with animal model) were found similar in both strains, being highest for BW (0.604 and 0.646) and EW (0.536 and 0.607) and lowest for IL (0.180 and 0.185 in M55 and V44, respectively). Annual genetic changes (BLUP) were:0.69 and 0.54 eggs for IL, 2.64 and 2.23 eggs for L44, -0.62 and -0.79 days for MAT, –0.09 and 0.16 g for EW, respectively for M55 and A44 strains.
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