A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge

The authors previously reported the construction of a glycoprotein E-deleted (gE-) mutant of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE-, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE-. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas non-vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE- could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE- was shown to be suitable for use as a BHV-1 differential vaccine viru

Genetic relationship between longevity and objectively or subjectively assessed performance traits in sheep using linear censored models

Genetic parameters of longevity in crossbred mule ewes, and genetic relationships among longevity, growth, body composition, and subjectively assessed traits on mule lambs and ewes have been estimated using Bayesian linear censored models. Additionally, the genetic associations between longevity and culling reasons were examined. Data comprised 1,797 observations of mule ewes for longevity, culling reasons, growth, body composition, mouth scores, and type traits. Longevity was defined as the time (in years) from 2 yr of age (the age at first lambing of most ewes) to culling or death. Censored data (i.e., observations for which only the lower bound of the true longevity is known, such as when the animals are still alive) comprised 24% of all observations for longevity. Bivariate analyses were used to analyze the longevity of the ewe with each performance trait by fitting linear Bayesian models considering censored observations. Longevity was split into 3 different sub-traits: age at culling due to teeth/mouth conditions, age at culling due to udder conditions, and age at culling due to other culling reasons. These sub-traits and their aggregation into the overall trait of longevity were analyzed in a multiple-trait model. The heritability of longevity was moderate at 0.27, whereas heritabilities of the growth and body composition traits ranged from 0.11 for average of shoulder, loin, and gigot conformation to 0.36 for ewe BW at first premating. Mouth scores and type traits had heritabilities ranging from 0.13 for jaw position to 0.39 for fleece quality. All analyzed traits showed low genetic correlations with longevity, ranging from –0.20 for average conformation scores in live animals to 0.18 for tooth angle. Teeth/mouth conditions resulted in the greatest heritability (0.15) among the sub-traits based on the separate culling reasons. Genetic correlations between separate culling reasons were low to high (0.12 to 0.63 for teeth/mouth conditions with udder conditions and other culling reasons, respectively). Longevity may be preferred as a selection criterion because of (i) its moderate heritability compared with its component sub-traits based on specific culling reasons, and (ii) its moderate to high genetic correlation with these component sub-traits. The moderate heritability for longevity reflects the potential of this trait for genetic improvement, especially when longevity is based on clearly defined culling reasons

Archaeal abundance in post-mortem ruminal digesta may help predict methane emissions from beef cattle

The Rowett Institute of Nutrition and Health and SRUC are funded by the Rural and Environment Science and Analytical Services Division (RESAS) of the Scottish Government. The project was supported by DEFRA and DA funded Agricultural Greenhouse Gas Inventory Research Platform. Our thanks are due to the excellent support staff at the SRUC Beef Research Centre, Edinburgh, also to Graham Horgan of BioSS, Aberdeen, for conducting multivariate analysis.Peer reviewedPublisher PD

Genetic associations of novel behaviour traits derived from social network analysis with growth, feed efficiency, and carcass characteristics in pigs

Reducing harmful aggressive behaviour remains a major challenge in pig production. Social network analysis (SNA) showed the potential in providing novel behavioural traits that describe the direct and indirect role of individual pigs in pen-level aggression. Our objectives were to (1) estimate the genetic parameters of these SNA traits, and (2) quantify the genetic associations between the SNA traits and commonly used performance measures: growth, feed intake, feed efficiency, and carcass traits. The animals were video recorded for 24 h post-mixing. The observed fighting behaviour of each animal was used as input for the SNA. A Bayesian approach was performed to estimate the genetic parameters of SNA traits and their association with the performance traits. The heritability estimates for all SNA traits ranged from 0.01 to 0.35. The genetic correlations between SNA and performance traits were non-significant, except for weighted degree with hot carcass weight, and for both betweenness and closeness centrality with test daily gain, final body weight, and hot carcass weight. Our results suggest that SNA traits are amenable for selective breeding. Integrating these traits with other behaviour and performance traits may potentially help in building up future strategies for simultaneously improving welfare and performance in commercial pig farms

Invited review:Novel methods and perspectives for modulating the rumen microbiome through selective breeding as a means to improve complex traits: Implications for methane emissions in cattle

The rumen microbiome is responsible for methane emission in ruminants. The study of microbes in the rumen has attracted great interest in the last decade. High-throughput sequencing technologies have been key in expanding the knowledge of the microorganisms that populate the rumen through metagenomic studies. There is substantial evidence that the composition of the rumen microbiota is influenced by host genotype. Therefore, modulation of the microbiota poses an important tool for breeding for lower emissions in large and small ruminants. The main challenges of metagenomic studies are addressed and some solutions are proposed when available, including the incorporation of metagenomic information into statistical models regularly used in animal breeding. To incorporate microbiome information into breeding programs, the particularities of the rumen microbiome must be considered, from sampling to inclusion in selection indices. The latest advances in this area are discussed in this review.Universidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de ZootecniaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigación en Nutrición Animal (CINA