Laying performance characteristics, egg quality, and integument condition of Saxonian chickens and German Langshan bantams in a free-range system

SUMMARY: Indigenous poultry breeds represent an important animal genetic resource. However, their characteristics in respect of performance, product quality, and integument condition are often poorly investigated. Therefore, the local breeds Saxonian chickens (SaChi) and German Langshan bantam chickens (GLB) of different plumage colors were characterized. The high-performing hybrid strain of Lohmann brown chickens (LB) served as the control group. For each group, 60 hens and 6 roosters were studied in an extensive free-range system from 21 to 80 wk of life. The plumage and foot pad quality were scored on 9 distinct observation dates and the measurements of the egg quality were performed at 7 different time periods.The number of eggs per hen housed in the first laying year was significantly lower in the SaChi (146.4 ± 30.8) and the GLB chickens (107.8 ± 20.4) when compared to the LB chickens (295.0 ± 16.8) (P < 0.001). Regarding laying performance, we detected effects of plumage color within both local breeds (P < 0.001). Within 4/7 plumage colors, effects of the breeder were also found (P ≤ 0.037). The eggs of the local chicken breeds showed lower egg weights (P < 0.001), shell breaking strength (P ≤ 0.041), albumen consistency (P < 0.001), and a lower egg shape index (P < 0.001), but higher proportions of yolk (P < 0.001) when compared to the eggs of the LB chickens. The logistic regression models for the plumage and footpad condition demonstrated that the SaChi and GLB hens underwent less plumage loss and footpad swelling than the LB hens (P < 0.001).Overall, this study shows that the laying performance of the local breeds was significantly lower, but there were noticeable advantages in terms of egg composition and animal welfare indicators when compared to a high-performing hybrid strain. In further studies and the use in extensive production systems, the observed performance differences between plumage colors and breeders should be taken into account

Multiple independent de novo mutations are associated with the development of schistosoma reflexum, a lethal syndrome in cattle.

Schistosoma reflexum (SR) is a lethal congenital syndrome characterized by U-shaped dorsal retroflexion of the spine and exposure of abdominal viscera. SR is usually associated with severe dystocia. The syndrome is thought to be inherited as a Mendelian trait. We collected a series of 23 SR-affected calves from four breeds (20 Holstein, one Red Danish, one Limousin, one Romagnola) and performed whole-genome sequencing (WGS). WGS was performed on 51 cattle, including 14 cases with parents (trio-based; Group 1) and nine single cases (solo-based; Group 2). Sequencing-based genome-wide association studies with 20 Holstein cases and 154 controls showed no association (above Bonferroni threshold; P-value<3×10-09). Assuming a monogenic recessive inheritance, no region of shared homozygosity was observed, suggesting heterogeneity. Alternatively, the presence of possible dominant acting de novo mutations were assessed. In Group 1, heterozygous private variants, absent in both parents, were found in seven cases. These involved the ACTL6A, FLNA, GLG1, IQSEC2, MAST3, MBTPS2, and MLLT1 genes. In addition, heterozygous private variants affecting the genes DYNC1LI1, PPP2R2B, SCAF8, SUGP1, and UBP1 were identified in five cases from Group 2. The detected frameshift and missense variants are predicted to cause haploinsufficiency. Each of these 12 affected genes belong to the class of haploinsufficient loss-of-function genes or are involved in embryonic and pre-weaning lethality or are known to be associated with severe malformation syndromes in humans and/or mice. This study presents for the first time a detailed genomic evaluation of bovine SR, suggesting that independent de novo mutations may explain the sporadic occurrence of SR in cattle

Rapid Discovery of De Novo Deleterious Mutations in Cattle Enhances the Value of Livestock as Model Species

Abstract In humans, the clinical and molecular characterization of sporadic syndromes is often hindered by the small number of patients and the difficulty in developing animal models for severe dominant conditions. Here we show that the availability of large data sets of whole-genome sequences, high-density SNP chip genotypes and extensive recording of phenotype offers an unprecedented opportunity to quickly dissect the genetic architecture of severe dominant conditions in livestock. We report on the identification of seven dominant de novo mutations in CHD7, COL1A1, COL2A1, COPA, and MITF and exploit the structure of cattle populations to describe their clinical consequences and map modifier loci. Moreover, we demonstrate that the emergence of recessive genetic defects can be monitored by detecting de novo deleterious mutations in the genome of bulls used for artificial insemination. These results demonstrate the attractiveness of cattle as a model species in the post genomic era, particularly to confirm the genetic aetiology of isolated clinical case reports in humans

Rapid Discovery of De Novo Deleterious Mutations in Cattle Enhances the Value of Livestock as Model Species

In humans, the clinical and molecular characterization of sporadic syndromes is often hindered by the small number of patients and the difficulty in developing animal models for severe dominant conditions. Here we show that the availability of large data sets of whole-genome sequences, high-density SNP chip genotypes and extensive recording of phenotype offers an unprecedented opportunity to quickly dissect the genetic architecture of severe dominant conditions in livestock. We report on the identification of seven dominant de novo mutations in CHD7, COL1A1, COL2A1, COPA, and MITF and exploit the structure of cattle populations to describe their clinical consequences and map modifier loci. Moreover, we demonstrate that the emergence of recessive genetic defects can be monitored by detecting de novo deleterious mutations in the genome of bulls used for artificial insemination. These results demonstrate the attractiveness of cattle as a model species in the post genomic era, particularly to confirm the genetic aetiology of isolated clinical case reports in humans.ISSN:2045-232