1. The effects of changes in technical efficiency on the increase of broiler production are presented for the period 1994–2013 based on the panel data from seven farms located in southern and central Poland. A total of 766 cycles were analysed.
2. The Cobb–Douglas production function was used to assess the changes of output elasticities as well as technical changes in broiler production, for 5-year sub-periods separately.
3. Technical indices of broiler production significantly improved between years 1994–2013: feed conversion ratio decreased from 2.50 kg/kg to 1.78 kg/kg, mortality rate from 8.8% to 4.0% and daily weight gain increased from 37.1 g/d to 58.7 g/d, respectively.
4. Before accession to the EU, there was a substantial increase of fixed capital connected with modernisation of buildings and equipment. In the period 1994–2013, inputs of fixed capital per kilogram of livestock increased by 72% and at the same time the input of labour decreased by 56%.
5. Technical changes in years 1994–1998 contributed to a rapid production increase at a rate of 4.6% annually and only by up to 0.7% annually during 2009–2013. The slowdown of production rate increase after 2009 was partially caused by decreasing the stocking density. 相似文献
Two 125‐day experiments of the same design were conducted to evaluate the effects of a heterotrophically grown microalgae (AURA) containing docosahexaenoic acid (DHA) on pig performance, carcass traits and the fatty acid composition of lean and adipose tissue. In each experiment, 144 Hypor pigs were blocked by sex, allocated to three treatment groups, and fed 0, 0.25% or 0.50% AURA in isonutritive, isocaloric diets. Pigs were weighed on days 0, 28, 56, 84 and 112. Feed and water intakes were measured every 28 days. Pigs were slaughtered on day 125. Data from the two studies were analysed as a single data set. Performance and carcass traits did not differ between treatments. Both microalgae treatment levels enriched (p <.05) Longissimus lumborum (LL) and backfat in DHA and improved (p <.05) their ratios of n‐6 to n‐3 fatty acids. 相似文献
Bone weight, defined as the total weight of the bones in all the forequarter and hindquarter joints, can reflect somebody conformation traits and skeletal diseases. To gain a better understanding of the genetic determinants of bone weight, we used a composite strategy including multimarker and rare‐marker association to perform genomewide association studies (GWAS) for that character in Simmental cattle. Our strategy consisted of three models: (i) A traditional linear mixed model (LMM) was applied (Q+K‐LMM); (ii) single nucleotide polymorphisms (SNPs) with p‐values less than .05 from the LMM were selected to undergo the least absolute shrinkage and selector operator (Lasso) in the second stage (LMM‐Lasso); (iii) genes containing two or more rare SNPs were examined by performing the sequence kernel association test (gene‐based SKAT). A total of 1,225 cattle were genotyped with an Illumina BovineHD BeadChip containing 770,000 SNPs. After the quality‐control procedures, 1,217 individuals with 608,696 common SNPs and 105,787 rare SNPs (with 0.001 < minor allele frequency [MAF] <0.05) remained in the sample for analysis. A traditional LMM successfully mapped three genes associated with bone weight, while LMM‐Lasso identified nine genes, which included all genes found by traditional LMM. Only a single gene, EPHB3, surpassed the significance threshold after Bonferroni correction in gene‐based SKAT. In conclusion, based on functional annotation and results from previous endeavours, we believe that LCORL, RIMS2, LAP3, PRKAR2B, CHSY1, MAP2K6 and EPHB3 are candidate genes for bone weight. In general, such a comprehensive strategy for GWAS may be useful for researchers seeking to probe the full genetic architecture underlying economic traits in livestock. 相似文献
In this research,12 heads of 28 to 30 months (low months age group) and 8 heads of 32 to 34 months (high months age group) Xinjiang Brown cattle steers which fed in the same mode of nutrition were chose for the slaughter test,in which the carcass traits,nutrient composition and some edible quality index were measured and comparative analyzed,a research which through comparative analysis the carcass traits and meat quality of nutritional components of different months of Xinjiang Brown cattle steers was carried out.The results indicated that the marbling,carcass grade,fat,meat color of high months age group were better than that of low months age group,the traits of the low months age group on fat color,moisture,protein,cooking loss and shear force value were better than that of high months age group,and there were significant difference on the traits of fat and meat color L* between the two groups (P<0.05),while the differences of other traits between them were not significant (P>0.05);As high-grade beef,in addition to the traits of meat color and pH value of the chunk roll,tenderloin and striploin,each site of the meat traits on the fat,protein,moisture,cooking loss,shear force value indicators were all better than other parts,and showed the best of nutritional value and edible quality.28 to 34 months of Xinjiang Brown cattle steers could produce high-grade beef,the meat could be used as the raw materials of steak and boiled beef. 相似文献