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Salmonella-infected poultry products are a major source of human Salmonella infection. The prophylactic use of antimicrobials in poultry production was recently banned in the EU, increasing the need for alternative methods to control Salmonella infections in poultry flocks. Genetic selection of chickens more resistant to Salmonella colonization provides an attractive means of sustainably controlling the pathogen in commercial poultry flocks and its subsequent entry into the food chain. Analysis of different inbred chickens has shown that individual lines are consistently either susceptible or resistant to the many serovars of Salmonella that have been tested. In this study, two inbred chicken lines with differential susceptibility to Salmonella colonization (6 and N) were used in a backcross experimental design. Unlike previous studies that used a candidate gene approach or low-density genome-wide screens, we have exploited a high-density marker set of 1255 SNPs covering the whole genome to identify quantitative trait loci (QTL). Analysis of log-transformed caecal bacterial levels between the parental lines revealed a significant difference at 1, 2, 3 and 4 days post-infection ( P < 0.05). Analysis of the genotypes of the backcross (F × N) population ( n = 288) revealed four QTL on chromosomes 2, 3, 12 and 25 for the two traits examined in this study: log-transformed bacterial counts in the caeca and presence of a hardened caseous caecal core. These included one genome-wide significant QTL on chromosome 2 at 20 Mb and three additional QTL, on chromosomes 3, 12 and 25 at 96, 15 and 1 Mb, respectively, which were significant at the chromosome-wide level ( P < 0.05). The results generated in this study will inform future breeding strategies to control these pathogens in commercial poultry flocks. [ABSTRACT FROM AUTHOR]

Thirty-one sets of N yield data were considered, taken from seven experiments grazed by sheep. N yield could be explained in terms of fertilizer N rate, an estimate of soil N and an interaction between the two. Fertilizer N increased grass N yield more on grazed swards than on cut swards, and this effect was greatest on soils with high available soil-N, It is concluded that N recirculation can be substantial on heavily-stocked swards receiving high rates of fertilizer N, so increasing the efficiency of fertilizer as a source of N in these conditions. [ABSTRACT FROM AUTHOR]

The importance of predicting grass N yield lies in its controlling influence on grass DM output and thus on animal production. Results from 88 experiments studying the use of fertilizer N on cut grass swards show that the major part (97%) of the variation in grass N yield could be explained in terms of fertilizer N rate, an estimate of soil N and an interaction between the two. From this, it appears that high fertilizer N recovery is associated with a high uptake of soil N and vice versa. [ABSTRACT FROM AUTHOR]

The article focuses on the research about poult enteritis and mortality syndrome suffered by turkeys in Great Britain. Because of the serious losses recorded by young turkey growers, poult vaccination was conducted to fight against turkey rhinotracheitis caused by avian pneumovirus. Some flocks became ill and deaths usually occur overnight. The most obvious clinical signs include lack of activity, reduced feed and water intake, scouring, and huddling.