The impact of direct-maternal genetic correlations on international beef cattle evaluations for Limousin weaning weight

In beef cattle maternally influenced traits, estimates of direct-maternal genetic correlations (r_dm) are usually reported to be negative. In international evaluations, r_dm can differ both within countries (r_{dm_WC}) and between countries (r_{dm_BC}). The r_{dm_BC} are difficult to estimate and are assumed to be zero in the current model for international beef cattle evaluations (Interbeef). Our objective was to investigate re-ranking of international estimated breeding values (IEBVs) in international beef cattle evaluations between models that either used estimated values for r_dm or assumed them to be 0. Age-adjusted weaning weights and pedigree data were available for Limousin beef cattle from ten European countries. International EBVs were obtained using a multi-trait animal model with countries modeled as different traits. We compared IEBVs from a model that uses estimated r_{dm_BC} (ranging between −0.14 and +0.14) and r_{dm_WC} (between −0.33 and +0.40) with IEBVs obtained either from the current model that assumes r_{dm_BC} to be 0, or from an alternative model that assumes both r_{dm_BC} and r_{dm_WC} to be 0. Direct and maternal IEBVs were compared across those three scenarios for different groups of animals. The ratio of population accuracies from the linear regression method was used to further investigate the impact of r_dm on international evaluations, for both the whole set of animals in the evaluation and the domestic ones. Ignoring r_{dm_BC}, i.e., replacing estimated values with 0, resulted in no (rank correlations > 0.99) or limited (between 0.98 and 0.99) re-ranking for direct and maternal IEBVs, respectively. Both r_{dm_BC} and r_{dm_WC} had less impact on direct IEBVs than on maternal IEBVs. Re-ranking of maternal IEBVs decreased with increasing reliability. Ignoring r_{dm_BC} resulted in no re-ranking for sires with IEBVs that might be exchanged across countries and limited re-ranking for the top 100 sires. Using estimated r_{dm_BC} values instead of considering them to be 0 resulted in null to limited increases in population accuracy. Ignoring both r_{dm_BC} and r_{dm_WC} resulted in considerable re-ranking of animals’ IEBVs in all groups of animals evaluated. This study showed the limited impact of the current practice of ignoring r_{dm_BC} in international evaluations for Limousin weaning weight, most likely because the estimated r_{dm_BC} was close to 0. We expect that these conclusions can be extended to other traits that have reported r_dm values in the range of r_{dm_WC} values for weaning weight in Limousin.     

基于改进生态足迹模型的西北地区生态可持续性评价

西北地区的生态可持续状况对于稳定生态环境,改善人地关系具有重要的现实意义。传统生态足迹模型(EFM)中存在诸多不足和缺陷,文中对原有模型进行了改进并对西北地区2012年生态可持续性进行了计算和评价。结果表明:1)西北地区人均生态足迹为2.90hm2/人,人均生态承载力为2.18hm2/人,人均生态赤字为0.72hm2/人,整体的生态结构不合理,处于不可持续状态;2)西北地区各省区的生态足迹差异明显,除青海和新疆为生态盈余外,其它省区均为生态赤字,其中陕西最大,甘肃最小;3)西北地区生态适度人口为0.74×108人,实际人口与生态适度人口的比例是1:0.75,人口数量整体处于超载状态;生态利用效率为0.65万元/hm2。改进生态足迹模型能够较好地评价生态可持续现状,研究方法和结果对于区域生态可持续发展研究具有一定的参考价值。     

葡萄枝屑栽培平菇的产量及营养成分效应研究

为解决平菇栽培原料供应价格飙升、供应紧张的现状,以平菇为试材,在平菇栽培培养料中按不同比例添加葡萄枝屑(0、30%、50%、70%),研究葡萄枝屑对平菇菌丝体生长、子实体产量及子实体营养成分的影响。先将葡萄枝屑、玉米芯、土霉素药渣等原料按不同比例浸泡混匀,装袋培养灰色平菇栽培种,采用柱前衍生反相高效液相色谱法测定平菇子实体氨基酸含量,按照国家标准测定方法测定平菇中微量元素含量。结果表明:添加适宜比例葡萄枝屑栽培平菇,菌丝体长势强,生长速率高,菌丝洁白、粗壮、紧密;添加葡萄枝屑可显著提高平菇产量,其中以添加50%葡萄枝屑的平菇产量最高(324.0 g/袋),且加入葡萄枝屑3个处理的生物学效率为90.3%~99.7%;添加葡萄枝屑可提高平菇子实体中铁、锌、硼等微量元素的含量;4个基质配方栽培的平菇基本能满足人体对必需氨基酸的搭配需求,且添加葡萄枝屑栽培的平菇赖氨酸含量显著高于不添加葡萄枝屑的对照。因此,加入葡萄枝屑可提高平菇的产量及微量元素含量,满足人体对必需氨基酸的需求。     

Genetic screening of FecB,FecXG and FecXI mutations and their linkage with litter size in Barki and Rahmani sheep breeds

Characterization of fecundity genes offers the opportunity to improve production efficiency, and the consequent increase in litter size in livestock industry, through utilizing them in breeding programs. The main objective of this study was to detect the BMPR‐IB, BMP15 and GDF9 gene mutations and to investigate whether these mutations are associated with litter size in Egyptian sheep breeds. To achieve this goal, 73 adult ewes representing Barki (n = 33) and Rahmani (n = 40) breeds were used. Polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) screening approach was used to detect the presence of FecB, FecX^G and FecX^I mutations in the two selected breeds. Results of this study showed that the three different candidate gene mutations, namely FecB, FecX^G and FecX^I are not present among these selected populations of the Egyptian breeds. Further studies regarding other mutations and/or other genes, which may influence ovulation rate, should be carried out to determine the type and mode of inheritance of such genes in Egyptian sheep breeds.     

Frequency of pancreatic amyloid deposition in cats from south-eastern Queensland

Summary Stereological procedures were used to estimate the amount of amyloid deposition in the pancreatic islets of 83 cats from random sources in south-eastern Queensland. Most had only minor deposits of less than 20% of islet volume (median 9%), but deposits equal to more than 50% of the islet volume were found in 10% of the cats. Amyloid deposition in pancreatic islets was correlated with the age of the cat. Although similar observations have been made previously in cats from the USA, the frequency of amyloid deposition was higher in this population of cats from south-eastern Queensland.     

Response of the pupil to steady-state retinal illumination: contribution by cones

Response of the pupil to steady-state retinal illumination was measured in an observer who lacked functioning rods. At high intensities, this response was as great as that of a normal eye. These results cannot be explained by the hypothesis that only rods are receptors for the steady-state response.     

Novel polymorphism of the canine dopamine receptor D4 gene intron II region

Various dog breeds are remarkably different from each other not only in their sizes and shapes but also in behavioral traits, suggesting that some of these characteristics are under genetic control. However, little is known about genes related to behavioral traits in canine species. In humans, it has been reported that the dopamine receptor D4 gene (DRD4) includes polymorphism at several regions that relate to personality or psychiatric disorders. In an earlier study by the authors of the present study, the polymorphisms in canine DRD4 exon III and exon I regions were reported. In the present study, a novel polymorphism in canine DRD4 intron II was found based on a 17 base pair insertion/deletion, and the two alleles detected were named P (shorter allele) and Q (longer allele). The allelic distribution in 28 breeds of dog, including a total of 1114 unrelated individuals, were then investigated. Both P and Q alleles were detected in most of the breeds investigated; however, the frequencies of P and Q differed greatly between breeds. With respect to classification based on breed origin, P and Q alleles were frequent in Occidental and Oriental breeds, respectively. Furthermore, two subspecies of wolves, the ancestors of dogs, were analyzed for the comparison of allele frequencies with dogs, and the P allele was predominant in both European and Chinese wolves.