Some sows habitually crush their piglets.

(agricultural Wealth net) Chen Fusheng, translated from Pig Progress 2002 Vol.18 No. 13, shows that some sows habitually cause the death of their own piglets. This information helps us to formulate elimination strategies and suggests that we can improve the motherhood of sows through genetic selection. The death of piglets before weaning has always been one of the important causes of economic losses in the pig industry, and picking up dead piglets is also an uncomfortable thing for any breeder. In different feeding systems, the types of death are also very different: in open captivity and outdoor feeding systems, crushing to death is more severely punished; for sows raised in birth cages, stillbirth and ferocious sows are severely punished. The mortality rate is relatively high in many open captive feeding systems, which shows that many pig farms have been struggling for this. In a production system, it is common to see some sows perform well, while others perform terribly. For example, in a small study of 46 new sows who gave birth in a pen, 3/4 of piglet deaths (mainly crushing) occurred in only 1/3 of sows. We want to find out whether the poor maternal performance of some new sows is whether they can become the characteristics of a sow so that the final sow will always reappear in the future. In order to find out whether the piglet death of a sow has been the same in the next few births, we analyzed the production records of a commercial pig farm over the past 11 years. The pig farm used litter cages for parturient sows, and we analyzed the records of the fourth to ninth litters of 125 Landrace final pigs. For each litter, we learned about the number of live and stillborn piglets (excluding mummified piglets) and the total weight of live piglets. For pre-weaning death, the date and cause of death were analyzed. The result is a depressing and familiar scene. In our statistics, 6.5% of the piglets were stillborn and 14.3% died before weaning. The main causes of these deaths were crushing (6.8%) and low vitality or hunger (4.4%). We rarely see ferocity in our analysis (< 0.2%), but this may be because ferocious new sows are often eliminated and do not enter the fourth child. Our analysis of risk factors focused on the three main causes of death (stillbirth, crushing, low vitality / hunger), as well as the total number of deaths of live piglets (regardless of the cause of death). The risk of death from all four causes is greater in large nests and in nests with lower birth weight. The process of labor in large nests is relatively long, which is more likely to cause hypoxia and lead to stillbirth in piglets. Fighting for nipples increases the nutritional stress of large litter piglets, which increases the likelihood of hunger. Underweight and hungry piglets stay close to the breast for a longer time, so they are at greater risk of being pressed and unable to escape when the sows lie down. Most types of deaths increase with the number of births (figure 1). There are more stillbirths in older sows, which may be due to prolonged peace of birth due to uterine muscle weakness. No matter what the cause of death in live piglets also increased with the increase of parity. Crush death especially increases with the number of births, which may be for a variety of reasons. Sows are getting older and older, and their flexibility in movement and ability to respond to the screams of pressed piglets may decrease, resulting in an increase in the incidence of crushing events. The response of sows to piglets decreases with age and experience. Unexpectedly, deaths from low vitality / hunger were not affected by parity, although older sows had lower lactation. Fig. 1 the mortality and the incidence of stillbirth and crushing of live piglets increase with the increase of parity, and so do deaths caused by low vitality and hunger (figure) in general, the analysis of death risk factors shows that the practice of selecting live litter size at the expense of birth weight increases the risk of piglets dying before weaning. The habit of sows after taking into account various factors affecting the death of piglets, the situation is still caused by a large number of piglet deaths caused by some sows. In each parity of the same sow, the risk of stillbirth and crushing of piglets is the same, and the total risk of postnatal death (death caused by any cause) of piglets is also quite consistent to a certain extent. The stillbirth and crushing of each parity of the same sow are highly repeatable. This may not be surprising, as it is likely to be directly related to the reproductive physiology and anatomy (stillbirth) of sows, as well as to the maternal behavior of sows (that is, death, although the vitality and behavior of piglets are also related). In some sows, the occurrence of self-death caused by low vitality of piglets is not consistent among the parities of the sows. The different effects caused by different boar genotypes may be one of the reasons for this phenomenon. Is it a genetic trait? the measured value of repeatability is corresponding to that of other reproductive traits, which indicates that it is possible to select low mortality of piglets, but relatively large genetic studies are needed. Hopefully, however, the huge differences between individuals in this study suggest that genetic progress is likely to be made if these traits are heritable. From the perspective of various causes of death, the best sows in this study never led to the death of piglets for this reason throughout their reproductive life. On the other hand, there are also "scary" sows. For example, one sow promotes 45.8% of her live piglets for various reasons, while another sow kills 30.8% of her piglets. For pig breeders, a sow performs consistently in all parities, meaning it is necessary to check the death records of its piglets when deciding which sow to eliminate (or which sow to match). Further studies are needed to determine whether the traits of sows that affect piglet mortality can be improved by genetic breeding. In the past, breeding companies have succeeded by increasing the number of live births. The selection of good motherhood may be another feasible way, which can be used to increase the number of weaned litters without increasing mortality so as not to be detrimental to the welfare of pigs and the evaluation of breeders. In our study, the protective nature of the litter cage probably masked the difference in the death rate of piglets that would have been shown by sows under open feeding conditions, because, under such conditions, the freedom of sows to show their good or bad motherhood is limited. In spite of this, we found that there were differences in the crush rate of piglets between different sows under the condition of free feeding or outdoor feeding. Under the condition of free feeding or outdoor feeding, it is likely to be more important to select individuals or genotypes with good maternal parturition. Original title: Sow consistency in crushing mortality (English) original author: Dr. Rick D'Eatrh and Dr. aSusan Jarvis (SCA, UK)-- Thank you for sharing, helping-- Thank you for sharing