Multi-trait genomic prediction in pigs using single and multistep methods based on the absorption of ungenotyped animals

acceptedVersio

Can we improve maternal care in sows? Maternal behavioural traits important for piglet survival in loose-housed sow herds

Author's accepted version (post-print).This is a pre-copyedited, author-produced version of an article accepted for publication in Journal of Animal Science following peer review. The version of record Ocepek, M., Rosvold, E. M., Andersen-Ranberg, I. & Andersen, I. L. (2017). Can we improve maternal care in sows? Maternal behavioural traits important for piglet survival in loose-housed sow herds. Journal of Animal Science, 95(11), 4708-4717 is available online at: https://doi.org/10.2527/jas2017.1725.Available from 02/11/2018.acceptedVersio

Management routines influencing piglet survival in loose-housed sow herds

Author's accepted version (post-print).Piglet mortality is still a significant welfare and ethical matter in pig production, as well as an economical challenge for the farmer. Most of the mortality occurs early after farrowing, and previous studies have shown that the farm's management routines, especially around farrowing, are important factors to reduce it. When sows are loose-housed at farrowing and in the following lactation period, it puts higher demands on management input from the farmer to keep piglet mortality low. The objective of this study was to assess the importance of different management routines around the time of farrowing, and other farm qualities for piglet survival in loose-housed herds. To study risk factors for herd piglet mortality, a cross-sectional field survey was carried out in Norway in the year 2013, and included 52 commercial herds with hybrid LY sows (Norwegian Landrace x Swedish Yorkshire). The farms were visited once, and the farmers answered a questionnaire about their management practices. The outcome was the average herd pre-weaning mortality in the years of 2012–2013. To include as many management factors as possible into the multivariable linear regression model, we generated a new variable based on 4 management routines: 3 routines at farrowing (presence at 80–100% of the farrowings, drying newborn piglets, and practice split suckling), and one concerning farmer´s contact with the sows. This variable was called “Management type” (M), and were divided into 4 categories with increasing effort; M1 herds without any of the 4 mentioned routines, M2 had contact with sows >2 times per day, M3 performed the 3 routines at farrowing, and M4 combined the high sow contact and the 3 routines. The predicted values of mean herd piglet mortality for M1, M2, M3 and M4 were 20.1%, 17.0%, 16.2% and 13.3% respectively. The farmer's increased management effort was associated with lower piglet mortality (P<0.05). The farmer's effort at critical times together with systematic and important routines, and having frequent contact with the sows, makes a huge difference for piglet survival. The farmers are credited for this work by having lower piglet mortality as a result.acceptedVersio

Sperm DNA integrity in Landrace and Duroc boar semen and its relationship to litter size

acceptedVersio

Can a super sow be a robust sow? Consequences of litter investment in purebred and crossbred sows of different parities

publishedVersio

Relationship between sperm motility characteristics and ATP concentrations, and association with fertility in two different pig breeds

acceptedVersio

Association between single-nucleotide polymorphisms within candidate genes and fertility in Landrace and Duroc pigs

Finding effective predictors of traits related to boar fertility is essential for increasing the efficiency of artificial insemi‑nation systems in pig breeding. The objective of this study was to find associations between single‑nucleotide poly‑morphisms (SNPs) within candidate genes and fertility in the breeds Landrace and Duroc. Animals with breeding val‑ues for total number of piglets born, were re‑sequenced for exonic regions of 14 candidate genes related to male and female fertility using samples from 16 Landrace boars and 16 Duroc boars (four with high and four with low breeding value of total number of piglets born for each breed for male fertility, and the same for female fertility) to detect genetic variants. Genotyping for the detected SNPs was done in 619 Landrace boars and 513 Duroc boars. Two SNPs in BMPR1 and one SNP in COX-2 were found significantly associated with the total number of piglets born in Landrace. In Duroc, two SNPs in PLCz, one SNP in VWF and one SNP in ZP3 were found significantly associated with total number of piglets born. These SNPs explained between 0.27% and 1.18% of the genetic variance. These effects are too low for being used directly for selection purposes but can be of interest in SNP‑panels used for genomic selection

Association between single-nucleotide polymorphisms within candidate genes and fertility in Landrace and Duroc pigs

Finding effective predictors of traits related to boar fertility is essential for increasing the efficiency of artificial insemi‑nation systems in pig breeding. The objective of this study was to find associations between single‑nucleotide poly‑morphisms (SNPs) within candidate genes and fertility in the breeds Landrace and Duroc. Animals with breeding val‑ues for total number of piglets born, were re‑sequenced for exonic regions of 14 candidate genes related to male and female fertility using samples from 16 Landrace boars and 16 Duroc boars (four with high and four with low breeding value of total number of piglets born for each breed for male fertility, and the same for female fertility) to detect genetic variants. Genotyping for the detected SNPs was done in 619 Landrace boars and 513 Duroc boars. Two SNPs in BMPR1 and one SNP in COX-2 were found significantly associated with the total number of piglets born in Landrace. In Duroc, two SNPs in PLCz, one SNP in VWF and one SNP in ZP3 were found significantly associated with total number of piglets born. These SNPs explained between 0.27% and 1.18% of the genetic variance. These effects are too low for being used directly for selection purposes but can be of interest in SNP‑panels used for genomic selection