A pioneering study by the Danish Pig Research Centre has confirmed pig sociability as a possible relevant trait in DanBred breeding goals. This new trait will add to the genetic progress.
丹麦养猪研究中心的一项开拓性研究证实，猪的社会性可能是丹麦育种目标中的一个相关特征。这种新特性将有助于基因的进化。
Positive social behaviour among pigs enhance the growth of pen mates and this tendency is passed down from generation to generation. In other words, it is heritable. A study performed by the Danish Pig Research Centre (DPRC) indicated how DanBred pigs, with a positive social genetic profile (social pigs), have a positive effect on the daily gain of their pen mates.
猪的积极社会行为促进了猪圈内同伴的成长，这种趋势代代相传。换句话说，这是可遗传的。丹麦生猪研究中心(DPRC)进行的一项研究表明，具有积极社会遗传特征的丹麦丹育种猪(“社会猪”)如何对其同圈生猪的日增重产生积极影响。
When accounting for both the direct effect of the pig’s own genes as well as the social genetic effect of others, the genetic gain in growth is potentially increased by 5-10%. That knowledge can be used to increase genetic gain for daily growth and improve the social behaviour and welfare of the breeding company’s pigs, so results and outcomes are limited to DanBred animals. All this was concluded as part of a large research project on the Landrace pigs between DPRC and Aarhus University, Denmark.
当考虑到猪自身基因的直接影响和其他猪的社会遗传影响时，生长中的遗传增益可能会增加5-10%。这些知识可以用来增加日常生长所需的遗传收益，改善育种公司种猪的社会行为和福利，结果和成效仅限于丹育种猪。这些都是丹麦生猪研究中心和丹麦奥尔胡斯大学开展的长白猪大型研究项目中的一部分。
Social behaviour in Danish Landrace pigs is heritable, recent research shows. Photo: DanBred
最近的研究表明，丹麦长白猪的社会行为是可遗传的。图：DanBred
The study
研究
The current study included the average daily gain (ADG) of 30 to 94 kg recorded on a total of 32,212 male and 48,252 female Landrace pigs. The pigs were raised in 13 nucleus herds in sex separated pens with between eight and 15 pigs per pen.
目前的研究包括32,212头长白公猪和48,252头长白母猪的平均日增重(ADG)，达30至94公斤。这些猪被分成13个核心群，分性别饲养，每猪圈有8到15头猪。
During the study the genetic variation and heritability for direct genetic effects (the effect of a pig’s genes on its own growth) and for indirect genetic effects (the effects of a pig’s genes on the growth of its pen mates) were estimated. The results showed a significant genetic variance for indirect genetic effects for ADG in both male and female pigs, which indicates that it is possible to select pigs for sociability in relation to growth.
研究中，对直接遗传效应(猪基因对其自身生长的影响)和间接遗传效应(猪基因对其同圈生猪生长的影响)的遗传变异和遗传力进行了估计。结果表明，雄性和雌性猪日增重的间接遗传效应存在显著遗传变异，这表明选择与生长相关的社会性猪是可能的。
The heritability for the pig’s own genetic potential was 22% and 24% for female pigs, whereas the estimated total heritability (i.e. the direct and indirect genetic potential combined) for male pigs was 32% and 27% for female pigs. That means that heritability increased by 45% in male and 13% in female pigs when accounting for the genetic background of social interactions, and that there is in fact an unused selection potential for growth. That potential can be used to make further genetic progress for ADG in breeding populations.
母猪自身遗传潜力的遗传力分别为22%和24%，而公猪的遗传力估计总和(即直接和间接遗传潜力的总和)分别为32%和27%。这意味着，考虑到社会互动的遗传背景，公猪的遗传力增加了45%，母猪的遗传力增加了13%，事实上，还有一种未被利用的生长选择潜力。这一潜力可用于在育种群体中进一步促进平均日增重的遗传进展。
Predicting the social potential
预测社会性潜力
In order to be able to conclude that genetic selection on social traits will result in genetic progress, it was necessary to account for all genetic variance. To overcome that very complex issue, DPRC also tested whether it would be possible to predict the genetic potential for social interactions purely based on the information from relatives.
为了能够得出社会性状的遗传选择导致遗传进展的结论，有必要考虑所有遗传变异。为了克服这个非常复杂的问题，DPRC还测试了是否有可能纯粹根据近亲的信息来预测社会互动的遗传潜力。
Unlike previous studies, the study shows very clearly that it is possible. In fact, the results showed that the so-called predictive ability for growth was improved by approximately 7% when accounting for the genetic potential for social interactions on top of the genetic potential for the pig’s own growth. Predictive ability is an analogue to accuracy of selection, which is an indicator of how much additional genetic gain can be achieved.
与以往的研究不同，这项研究非常清楚地表明这是可能的。事实上，研究结果表明，当考虑到猪自身生长的遗传潜力之外的社会互动的遗传潜力时，所谓的生长预测能力提高了约7%。预测能力类似于选择的准确性，这是一个指标，表明可以获得多少额外的遗传增益。
Because previous studies have found gender differences in behaviour, the current study also hypothesised that test results may differ between male and female finishers. It is expected that male pigs show more aggressive behaviour than female pigs. The issue is, however, more complex. In the current study, the results show that there is competition between female pigs, but none between male pigs.
由于之前的研究发现了行为上的性别差异，目前的研究还假设，雄性和雌性育肥猪的测试结果可能不同。公猪比母猪具有更强的攻击性。然而，这个问题更为复杂。目前的研究表明，母猪之间存在竞争，而公猪之间则没有。
In the words of senior scientist Birgitte Ask, DPRC, the explanation is as follows: “This study shows that female Landrace pigs, which have a high genetic potential for their own growth, tend to inhibit the growth of their pen mates, whereas this is not the case in male Landrace pigs. In practice, this means that if the genetic potential for social interactions is unaccounted for, then the realised growth of female pigs will be lower than expected based on their genetic potential for their own growth. This information is very important to maximise the genetic gain for growth, not least when estimating the genetic potential for growth in selection candidates in nucleus herds.”
用DPRC资深科学家Birgitte Ask的话说， “这项研究表明，具有高生长基因潜力的雌性长白猪，往往会抑制其圈养伙伴的生长，而雄性土猪则不同。在实践中，这意味着如果没有考虑到社会互动的遗传潜力，那么基于母猪自身生长的遗传潜力，母猪的实际生长速度将低于预期。这一信息对于最大限度地提高生长所需的遗传收益非常重要，尤其是在估计核群中候选种猪生长所需的遗传潜力时。”
When accounting for the above-mentioned differences between male and female pigs regarding genetic potential for social interaction, the predictive ability for male and female growth is improved by approximately 15% and 4% respectively. Altogether, that implies that accounting for gender differences can give an additional increase in genetic gain for growth. In particular as selection intensities are higher in males than females, improving the accuracy with which the genetic potential for growth of male selection candidates can be predicted has a larger impact on the selection response than an equivalent improvement in the accuracy for female selection candidates.
当考虑到上述公猪和母猪在社会互动遗传潜能方面的差异时，公猪和母猪的生长预测能力分别提高了约15%和4%。总的来说，这意味着对性别差异的考虑可以增加生长所需的基因增益。特别是当选择强度在公猪中高于母猪时，提高预测雄性候选种猪的生长遗传潜力的准确性比同等提高雌性候选母猪的准确性对选择反应的影响更大。
Improving own and pen mates’ growth
促进自身和同圈生猪的生长
By considering the social genetic potential for growth in a breeding programme, it will be possible to improve not only the pig’s own genetic potential for growth, but also the pig’s genetic potential to stimulate the growth of its own pen mates.
通过在育种计划中考虑社会遗传潜力的增长，不仅有可能提高猪自身的遗传潜力的增长，而且也有可能提高其刺激同圈生猪生长的遗传潜力。
It is the hypothesis and goal that such an improvement will also lead to favourably correlated responses in damaging behaviours of group housed pigs. To test this hypothesis, DPRC recently completed another large-scale selection experiment with recordings of tail and ear biting injuries and skin lesions from fighting on approximately 4,500 crossbred offspring in 270 groups. Results from this experiment are expected by the end of 2019.
假设这种改善也将对群养猪的破坏行为产生有利反应。为了验证这一假设，DPRC最近完成了另一项大规模的选择实验，记录了270组约4500个杂交后代在打斗中受到的咬尾、咬耳和皮肤损伤。这项实验预计将于2019年底前得出结果。
The full scientific article has been published in the journal of Genetics Selection Evolution, February 2018. The work has been partially funded by the Green Development and Demonstration Program by the Ministry of Environment and Food of Denmark.
这篇科学论文完整版发表在2018年2月的《遗传学选择进化》杂志上。这项工作的部分资金由丹麦环境和食品部绿色发展和示范项目提供。
来源：Pig Progress
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（文/爱猪网记者刘坤颖编译，爱猪网原创，转载请注明出处）
