Is it Farmer’s Major Problem on Swine Production?
Locomotion is an important factor in whole pig production. With locomotion, pigs will be able to gather feed and move freely as they want. Failures in locomotion will not only decreases pig productivity, increases the stress level, but also against the animal welfare ethics. Osteochondrosis, more or less associated with the movement issue in swine production, at least it can make animals feel pain and decreases animal welfare. In this paper, I will focus on the mechanism of how osteochondrosis happens and its severity, relevance to locomotion problem, its impact on the livestock production, and in the end, try to construct an answer to the central question in the subtitle of this paper.
To begin with, I will briefly discuss how osteochondrosis happens. Osteochondrosis is one of the developmental orthopaedic disease that is encountered worldwide (Ekman et al., 2009). Osteochondrosis occurs when there is a focal disturbance in endochondral ossification that may result in the malfunction of the blood supply to epiphyseal growth (Olstad et al., 2015). This failure started when there is a leakage of blood vessels between metaphysis and epiphysis sections inside the extension sections of articular-epiphyseal cartilage complex (AECC). This leakage may be caused by the disruption of anastomoses connection which is a weak binding between growing blood vessels across regions to undergo the longitudinal growth of metaphyseal growth cartilage and the spherical growth of epiphyseal growth cartilage (Ytrehus et al., 2004). This leakage may cause necrosis cells in the resting zone that disrupting matrix calcification or vascular invasion, and the matrix does not become converted to bone (Ytrehus et al., 2007). It is still unclear of what factor that causes this leakage, as this disease’s cause are multifactorial including both genetic and environmental factors (de Koning et al., 2014). However, it is likely caused mainly by the overpressure of the animal’s upper body, caused by weight, activity, and heredity (Ytrehus et al., 2007; Wittwer et al., 2009).
Overpressure in the cartilage may be caused by the high growth of the animal itself. Van Grevenhof et al. (2012) studied that at the latter stages of pig’s life (from weaning onwards), pigs diagnosed with minor or severe osteochondrosis were having a higher body weight than that without osteochondrosis. This fact then makes sense with the simple logical paradigm that joints that receive heavier weight from the upper body will be more prone to injuries that disrupt anastomoses connection between blood vessels in the epiphyseal and metaphyseal regions. Body weight will be connected with nutrition as well. A study by De Koning (2013) resulted that gilts that fed ad libitum diet in their later life (10 weeks onwards), preceded by restricted diet in their earlier life have higher prevalence of osteochondrosis than they that fed all time ad libitum diet, all time-restricted diet, and ad libitum switched to restricted diet. This is also logical since there is a possibility that gilts that fed ad libitum diet in their earlier life have already optimised their bone and muscular capacity to support the expected high body weight in their late life. However, if this feed restriction implemented into swine production industry, in my opinion, there will be no optimum efficiency, since it will not yield maximum average daily gain or total body weight at slaughter age.
The severity of osteochondrosis can be divided into three categories: latens, manifesta, and dissecans (Ytrehus et al., 2007). In osteochondrosis latens, the necrosis cells are located in the resting zone of
the growth cartilage, which not overlying the articular cartilage or subchondral bone. Whereas, osteochondrosis manifesta resulting the necrosis up into the subchondral bone. The most severe one, osteochondrosis dissecans, may lead to a rupture of articular cartilage because there is an overlying necrotic cartilage cell inside region of articular cartilage (Ytrehus et al., 2007). In my opinion, all these three conditions can make piglets in pain, since there are abundant nervous tissues in metaphyseal and lower epiphyseal regions.
Osteochondrosis is one of the abnormalities that may lead to locomotion problem. Nonetheless, it is still unclear about the exact number on how much the contribution of osteochondrosis in movement problems. In my opinion, since there is an existence of pain, animals will suffer from osteochondrosis. This shocks will make the animal prevent to move actively (Van Grevenhof et al., 2012). In the end, it may drive to different production problem such as low feed intake as a result of locomotion problem.
Osteochondrosis increases the risk of premature culling (De Koning et al., 2012). A study by Kirk et al. (2005) resulted that 72% of mortality of pigs were associated with the locomotive problem, which arthritis caused 24% of locomotion disorders. Ytrehus et al. (2007) affirmed that severe osteochondrosis (dissecans) might lead to osteoarthritis if there is an overweight of animal’s body. This high number of mortality is associated with the premature culling. Most of the pigs that have locomotive disorders are intentionally killed, as an action of culling. Another statement from Kirk et al. (2005) is that 49% of 35 sows that he randomly selected are suffering from osteochondrosis. This finding convinces us that the prevalence of osteochondrosis is considerably high, although this is only found in one herd. These premature culling may have an impact on economics aspect of the livestock production, despite there is no clear and consistent connection yet.
Studies also focused on the clinical aspect such as gait scoring to detect whether a pig suffers osteochondrosis or not. Stavrakakis et al. (2014) reported that pigs with clinical deficiencies and degenerative joint lesions had altered kinematics. Gait or movement patterns were significantly associated with the occurrence and severity of osteochondrosis (De Koning et al., 2012). However, Etterlin et al. (2015) stated that the association between gait score and joint condemnation caused by osteochondrosis appeared to be poor.
After studied several works of literature, I came up with this conclusion. Osteochondrosis can lead to locomotion problem in pigs. The prevalence is relatively high in one herd, also can lead to another physiological stress that causes lower productivity, premature culling, welfare issue, and economics losses. However, that impact is still unclear until I write this paper and several pieces of literature not that convinced to link causal interrelation between osteochondrosis and production problems. Because of that condition, I will say that osteochondrosis is a major problem only when there is a case that pigs are lame because of osteochondrosis so that pigs cannot moves freely as they want and cannot grow as it have to. I believe there are studies still in progress on how to detect osteochondrosis clinically without sacrifices pigs to be slaughtered. Until that time, I will conclude that osteochondrosis is a middle priority problem because its occurrence is varied in each herd and cannot be generalised yet. Hence, the impact is also varied regarding production and needed different approach and handling in different herd condition.
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