The genetic and phenotypic associations between lamb survival outcomes and other traits recorded at lambing

Context. Australian sheep breeding values (ASBVs) for lambing ease (LE) are estimated by Sheep Genetics, by using a threshold animal model at the lamb level, in a tri-variate analysis that includes data on birth weight, gestation length and lambing ease score. The implications of these traits for lamb survival, or the use of other indirect traits to improve accuracy of ASBVs for LE, are not currently being considered. Ultimately, it is desirable to extend the analysis to outcomes for individual lamb survival. Aim. The present study investigated implications of LE for lamb survival outcomes, accounting for litter size, and examined associations with other traits recorded at or shortly after lambing in maternal sheep breeds.Methods. Equivalent linear models were used to compare lamb- and ewe-level models with various combinations of additional random effects. In particular, lambing ease was treated as a different trait for single-born and twin-born lambs, to identify changes in genetic correlations associated with litter size between LE and other traits. Other traits included lambs recorded dead at birth, survival to weaning, lamb birth weight, gestation length and maternal behaviour score.Key results. Individual lamb survival outcomes inferred from field data and dead at birth lambs, are lowly heritable traits influenced by both direct and maternal effects. Lamb survival is positively correlated with birth weight, but negatively correlated with gestation length, lambing ease score (increasing lambing difficulty) and dead at birth lambs. Genetic and phenotypic correlations demonstrated that birth weight and lambing ease are antagonistic traits, more so for single-born lambs. Genetic correlations were moderate between dead at birth lambs and LE (0.40–0.45 singles; 0.15–0.36 including data from twins) or lamb survival (−0.63 to −0.81 singles; −0.00 to −0.23 including data from twins) and can add to the accuracy of genetic evaluation for these traits. In contrast, maternal behaviour score was predominantly an ewe trait, and will therefore add to accuracy of evaluation only for maternal effects. Lamb-level models appeared to underestimate heritability, sometimes compensated for by larger variance, and over-estimate genetic correlations for some traits relative to ewe-level models.Conclusions. Expanding the current lambing ease analysis to include dead at birth records and lamb survival outcomes would provide more detailed options for breeders to develop breeding goals to improve outcomes for both ewes and lambs. Further work is required to expand analyses to include threshold and continuous traits and understand genetic contributions to ewe survival traits.Implications. Relative selection emphasis on LE and birth weight must be considered in light of the expected litter size in which lambs will be born, to ensure favourable outcomes for lamb survival overall. Accuracy of genetic evaluation for LE can be improved using data on dead at birth. Equivalent ewe model analyses are possible. Completeness of pedigree, availability of informative lamb level data and integration with other traits are also factors to consider for the choice between operational lamb- versus ewe-level models for genetic evaluation systems

Typing Late Prehistoric Cows and Bulls—Osteology and Genetics of Cattle at the Eketorp Ringfort on the Öland Island in Sweden

Human management of livestock and the presence of different breeds have been discussed in archaeozoology and animal breeding. Traditionally osteometrics has been the main tool in addressing these questions. We combine osteometrics with molecular sex identifications of 104 of 340 morphometrically analysed bones in order to investigate the use of cattle at the Eketorp ringfort on the Öland island in Sweden. The fort is dated to 300–1220/50 A.D., revealing three different building phases. In order to investigate specific patterns and shifts through time in the use of cattle the genetic data is evaluated in relation to osteometric patterns and occurrence of pathologies on cattle metapodia. Males were genotyped for a Y-chromosomal SNP in UTY19 that separates the two major haplogroups, Y1 and Y2, in taurine cattle. A subset of the samples were also genotyped for one SNP involved in coat coloration (MC1R), one SNP putatively involved in resistance to cattle plague (TLR4), and one SNP in intron 5 of the IGF-1 gene that has been associated to size and reproduction

Gilts and sows adapt feed intake and feeding behaviour differently when moved into dynamic groups with electronic sow feeders

Introduction: Disruption of feed intake during gestation has detrimental effects on reproductive performance and increased sow removals (Vargovic et al., 2021). The purpose of this study was to investigate whether the introduction of new sows to existing group-housed sows was associated with disruptions to feed intake or changes to feeding behaviour

Ranking for fight lesion scores is not consistent over time

Aggressive behaviours such as fighting compromise the welfare of group-housed gilts and sows. The extent of lesions that result from fighting is a simple measure of the aggression received by individual animals within a group, and is a potential measure of individual behaviour (Turner et al. 2006). However, group dynamics and individual behaviour can change over time. The hypothesis investigated in this study was that for individual gilts regrouped within parity over time, post-selection and pre-farrowing lesion scores might not be a consistent indicator of aggressive behaviours

The effect of fostering status and nurse sow parity on pre-weaning survival

Application Optimising fostering procedures to maximise piglet survival in commercial farrowing houses. Introduction Fostering is a process by which nursingpiglets are moved from one sow to another and is generally performed to even out litter size, matching the number of piglets to be suckled with the number of sow teats available (APL,2017), typically before two days of age. Other reasons for fostering include when piglets appear to be losing condition, the sow is savaging piglets or is unable to care for the litter,or sow death (Heim et al., 2012) which generally occurs after two days of age. The aim of this study was to investigate the effect of nurse sow parity on the survival of piglets either not fostered or fostered up toor after two days of age

Improve your social license - Breed sheep for disease resistance

Consumer interests in the health and welfare of animals has increased as production systems become more transparent. This brings about a need for cultural change around how the industry approaches the long-term management of disease traits. Genetic tools have been used by leading sheep breeders for decades to bring about genetic gain in production traits. The same approach can also be applied to breeding for good health and welfare. This paper provides a summary of the steps required to develop long-term solutions to diseases outbreaks allowing sheep producers to breed for disease resistance and improve the social license for the agricultural industry

Genetic parameters for urinalysis traits recorded on gestating sows

Urinalysis can be used to detect sows that typically remain unidentified with health conditions such as urinary tract infection, and also provides data on physiological variables reflecting metabolic status (e.g. glucose, ketones). The urine was collected from gilts and sows (N=694) after animals were transferred to the farrowing shed. The traits were defined from the urinalysis test strip results, with additional subjective measurements of odour, colour and turbidity. Subsequently, a trait representing urinary tract infection was defined. Heritability estimates were in a range 0.08 to 0.36, except for the presence of blood (0.03). Strong genetic correlations were estimated between bilirubin and urobilinogen (0.78), but not other trait combinations. The study demonstrated that several urinalysis traits could be considered as selection criteria for increasing the health status of sows. However, alternative procedures to collect phenotypes are required to improve ease of data collection. The associations of urinalysis parameters with breeding objective traits requires further investigation

The value of innate sow appetite as a model trait for maternal breeding objectives

The concept presented here evaluated benefits of including 'innate appetite' as an additional source of information to enhance response within a maternal breeding objective. The term 'innate appetite' refers to (heritable) feed intake (or comparable feeding behaviour) data recorded at any point in a sows' life-cycle, reflecting an animals desire to eat. When 'innate intake' was included as a selection criterion, the overall response increased from $41.98 to$47.31. The main proportion of the overall response was attributed to traits recorded on growing pigs. At the same time, farrowing and pre-weaning survival, wean-to-conception interval and longevity improved. Maternal breeding objectives in pigs can be extended by using innate appetite data, provided that uncertainty of genetic parameters, in particular between traits of growing pigs and sows is clarified

Phenotypic trade-offs between lambs and wool reflect weak antagonistic genetic correlations between reproductive and wool traits

Rearing lambs while producing wool is an annual source of competition for available nutritional resources supplied to breeding ewes. Genetic correlations between wool and reproductive traits were estimated from industry data, comparing models that did or did not account for the effects of reproductive level on wool traits recorded at different wool age stages (yearling, hogget, adult). Small to moderate antagonistic correlations between wool and reproductive traits tended to decrease in magnitude when birth -rear type of the individual (yearling and hogget stages) or reproductive output (adult ewes) were accounted for in models for wool traits. Increased recording of reproductive performance would make it possible to more accurately compare young animals for wool traits as well as genetically improve both trait sets (ewe reproduction and wool traits) for Merinos

Economic benefit of additional recording for welfare traits in maternal breeding objectives for pigs

The purpose of this study was to investigate, using selection index calculations, the economic benefits of improving welfare by expanding recording within traditional pig breeding programs to include welfare-related traits. The genetic parameters were adapted from several Australian studies. A basic breeding objective including average daily gain, backfat thickness and number of piglets born alive was extended to include welfare traits and feed conversion ratio (FCR). Welfare traits were: survival of piglets at farrowing (FS) and until weaning (PWS), weaning to conception interval (WCI), sow mature weight (MWT) and sow longevity (LONG). Sow appetite before farrowing (FRBF) and body condition before farrowing (CAL) were considered as additional selection criteria. When welfare traits were absent from the breeding objective and selection criteria, this resulted in reduced LONG, higher MWT, prolonged WCI and overall lower genetic response in the index in comparison with other scenarios. Valuing and recording welfare traits resulted in desirable responses for both production and welfare traits and increased overall economic merit. Including FCR in the breeding objective made it more difficult to improve welfare traits, particularly if FCR was recorded