Associated effects of copy number variants on economically important traits in Spanish Holstein dairy cattle.

Copy number variants (CNV) are structural variants consisting of duplications or deletions of genomic fragments longer than 1 kb that present variability in the population and are heritable. The objective of this study was to identify CNV regions (CNVR) associated with 7 economically important traits (production, functional, and type traits) in Holstein cattle: fat yield, protein yield, somatic cell count, days open, stature, foot angle, and udder depth. Copy number variants were detected by using deep-sequencing data from 10 sequenced bulls and the Bovine SNP chip array hybridization signals. To reduce the number of false-positive calls, only CNV identified by both sequencing and Bovine SNP chip assays were kept in the final data set. This resulted in 823 CNVR. After filtering by minor allele frequency >0.01, a total of 90 CNVR appeared segregating in the bulls that had phenotypic data. Linear and quadratic CNVR effects were estimated using Bayesian approaches. A total of 15 CNVR were associated with the traits included in the analysis. One CNVR was associated with fat and protein yield, another 1 with fat yield, 3 with stature, 1 with foot angle, 7 with udder depth, and only 1 with days open. Among the genes located within these regions, highlighted were the MTHFSD gene that belongs to the folate metabolism genes, which play critical roles in regulating milk protein synthesis; the SNRPE gene that is related to several morphological pathologies; and the NF1 gene, which is associated with potential effects on fertility traits. The results obtained in the current study revealed that these CNVR segregate in the Holstein population, and therefore some potential exists to increase the frequencies of the favorable alleles in the population after independent validation of results in this study. However, genetic variance explained by the variants reported in this study was small.

Does wing use and disuse cause behavioural and musculoskeletal changes in domestic fowl (Gallus gallus domesticus)?

Domestic chickens may live in environments which restrict wing muscle usage. Notably, reduced wing activity and accompanying muscle weakness are hypothesized risk factors for keel bone fractures and deviations. We used radio-frequency identification (RFID) to measure duration spent at elevated resources (feeders, nest-boxes), ultrasonography to measure muscle thickness (breast and lower leg) changes, radiography and palpation to determine fractures and deviations, respectively, following no, partial (one-sided wing sling) and full (cage) immobilization in white- and brown-feathered birds. We hypothesized partially immobilized hens would reduce elevated resource usage and that both immobilization groups would show decreased pectoralis thickness (disuse) and increased prevalence of fractures and deviations. Elevated nest-box usage was 42% lower following five weeks of partial immobilization for brown-feathered hens but no change in resource usage in white-feathered birds was observed. Fully immobilized, white-feathered hens showed a 17% reduction in pectoralis thickness, while the brown-feathered counterparts showed no change. Lastly, fractures and deviations were not affected in either strain or form of wing immobilization; however, overall low numbers of birds presented with these issues. Altogether, this study shows a profound difference between white- and brown-feathered hens in response to wing immobilization and associated muscle physiology.

Technology and Poultry Welfare.

Consideration of animal welfare is essential to address the consumers' demands and for the long term sustainability of commercial poultry. However, assessing welfare in large poultry flocks, to be able to detect potential welfare risks and to control or minimize its impact is difficult. Current developments in technology and mathematical modelling open new possibilities for real-time automatic monitoring of animal welfare and health. New technological innovations potentially adaptable to commercial poultry are appearing, although their practical implementation is still being defined. In this paper, we review the latest technological developments with potential to be applied to poultry welfare, especially for broiler chickens and laying hens. Some of the examples that are presented and discussed include the following: sensors for farm environmental monitoring, movement, or physiological parameters; imaging technologies such as optical flow to detect gait problems and feather pecking; infrared technologies to evaluate birds' thermoregulatory features and metabolism changes, that may be indicative of welfare, health and management problems. All these technologies have the potential to be implemented at the commercial level to improve birds' welfare and to optimize flock management, therefore, improving the efficiency of the system in terms of use of resources and, thus, long term sustainability.