| 1. |
- Lundeheim, Nils, et al.
(författare)
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Shoulder ulcers in sows are genetically correlated to leanness of young pigs and to litter weight
- 2014
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Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 64, s. 67-72
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to estimate the heritability for shoulder ulcers (SU) and sows' body condition at weaning (BCw), and the genetic correlations between these traits and some production and reproduction traits included in the current breeding goal of sow lines. The analyses were based on data on Swedish purebred Yorkshire from nucleus as well as multiplier herds. The estimated heritabilities were for BCw 0.21, and for SU 0.13. Significant genetic correlations were found between sidefat thickness (at 100 kg) and BCw (thicker fat layer at 100 kg - better condition at weaning), between sidefat thickness and SU (thicker fat layer - less SU), between litter weight at 3 weeks and BCw (heavier litter - lower body condition) and between litter weight at 3 weeks and SU (heavier litter - more SU). The genetic correlation between BCw and SU was also significant (lower body condition - more SU).
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| 2. |
- Lundgren, Helena, et al.
(författare)
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Genetic analysis of reproductive performance in Landrace sows and its correlation to piglet growth
- 2010
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 128, s. 173-178
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the reproductive performance of sows, including the interval from weaning to service after 1st litter and litter size in the following (2nd) parity, as well as the direct and maternal genetic effects of piglet growth on these reproduction traits. Data on 15 946 Norwegian Landrace sows' 1st and 2nd parity, and on 106,962 piglets born in 11,323 1st parity litters were included in the analyses, in total, five traits were analysed. Weaning-to-service interval was based on a 1- to 7-day interval (WS17) or a transformed 1- to 50-day interval (WS150). A third reproduction trait was total number of piglets born in 2nd parity (NBTnext). Piglet weight was included in the analyses, either as average piglet weight in the litter at 3 weeks of age (meanW3) or as individual piglet weight gain during the first 3 weeks of life (IWG03). Genetic parameters were estimated with animal models, including both direct and maternal effects for IWG03. Heritability estimates for WS17, WS150 and NBTnext were 0.08, 0.03 and 0.09 respectively. For meanW3. the heritability estimate was 0.21. For IWG03, the direct and maternal heritability estimates were 0.15 and 0.10 respectively. Negative and unfavourable genetic correlations were estimated between meanW3 and NBTnext (r(g) = -0.37), and between IWG03(maternal) and NBTnext (r(g) = -0.39). The ability to raise fast growing, heavy piglets seems to have an unfavorable effect on total number born in next litter but not on the weaning-to-service interval. (C) 2009 Elsevier B.V. All rights reserved.
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| 5. |
- Lundgren, Helena, et al.
(författare)
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Genetic parameters for feed intake, litter weight, body condition and rebreeding success in primiparous Norwegian Landrace sows
- 2014
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Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 8, s. 175-183
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to estimate genetic parameters for feed intake recorded as farmers' perception of young sows' appetite for the first 3 weeks of lactation (APP) and feed intake recorded for one day in the 3rd week of lactation (FEED), litter weight (LW) at 3 weeks, sow body condition at weaning (BC) and the following five reproduction traits: weaning-to-service interval of 1 to 7 days (WSI7), weaning-to-service interval of 1 to 50 days (WSI50), delayed service or not (DELAYED), pregnant on first service or not (PREGNANT) and litter size in 2nd parity (NBT2). The analyses included data on 4606 Norwegian Landrace 1st-parity sows and their litters. The Gibbs sampling method was used. The traits DELAYED and PREGNANT were analysed as threshold traits and APP, FEED, LW, BC, WSI7, WSI50 and NBT2 were analysed as linear traits. The heritability estimates for APP and FEED were low (<0.1), whereas the estimates for DELAYED and PREGNANT were rather high (0.4 and 0.3). The heritability estimate for BC was 0.2. The genetic correlations confirmed the complexity of breeding for sow performance; selection for heavy 1st litters may lead to lower body condition at weaning, which in turn leads to lower reproductive performance and smaller litters in 2nd parity. Selection for higher sow feed intake would improve body condition, but the simple way of measuring feed intake tested in this study (APP and FEED) cannot be recommended because of the low heritability obtained for these traits.
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| 6. |
- Lundgren, Helena, et al.
(författare)
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Genetics of growth in piglets and the association with homogeneity of body weight within litters
- 2010
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Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 88, s. 1240-1247
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to examine the genetic basis of homogeneity in piglets and the genetic correlations with litter size and growth during lactation. Genetic parameters for variation in piglet BW within litters at birth and at 3 wk of age, and in the BW of individual piglets at 3 wk (BW3) were estimated from the Norwegian Landrace nucleus population. Data on BW3 were collected from 146,572 piglets from 14,045 litters in 58 herds. Body weight at birth and at 3 wk of age was recorded for 13,318 piglets from 5 nucleus herds. Litter data were evaluated using multivariate trait models. The heritability estimates for the SD of BW at birth and at 3 wk (SDBW3) were in agreement with the literature (0.10 and 0.08, respectively). The genetic correlation for the number of piglets born alive and the mean BW at 3 wk was negative (-0.40 +/- 0.07), and the correlation of number of piglets born alive with SDBW3 was close to zero (-0.03 +/- 0.11). The genetic correlation between the SD of BW at birth and SDBW3 was moderate (0.51 +/- 0.31). The mean BW at birth was genetically correlated with mean BW at 3 wk (0.59 +/- 0.16) but was independent of SDBW3 (0.08 +/- 0.27). The estimates of direct and maternal heritability for BW3 were 0.03 and 0.07, respectively, and the genetic correlation between the 2 components was negative (-0.43 +/- 0.10). The genetic correlation of SDBW3 with the maternal effect on BW3 was positive and strong (0.66 +/- 0.08), whereas a negative correlation was found with the direct effect on BW3 (-0.18 +/- 0.14). These results suggest that it is possible to select for mean BW at birth without an increase in within-litter heterogeneity at 3 wk of age. A more efficient strategy would be to consider both the direct and the maternal effects on BW3 in the genetic evaluation, together with SDBW3. Thus, it is possible to avoid the increase in within- litter heterogeneity that would occur as a result of selection performed at 3 wk on a litter trait such as mean BW.
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