Muscle Pain

Acute soreness or pain occurs during and immediately following exercise. This condition is short-lived and is alleviated when exercise is discontinued. Acute soreness is thought to be associated with lack of adequate blood flow or ischemia to the active muscles. These theories are discussed in light of current biochemical and morphological findings. From recent studies designed to induce delayed soreness, it has been found that the degree of delayed soreness experienced with exercise is related to the type of muscle contraction performed. Maximum soreness is associated with eccentric types of contractions. A possible explanation for this finding is presented. When we carry out a bout of intense exercise we can, at times, reach the point where the exercise becomes painful. But as soon as we stop, the pain subsides. However, there is one form of exercise, eccentric exercise, where there is typically no pain immediately after the exercise, but we find ourselves stiff and sore next day. The soreness can persist for 4–5 days, depending on the severity of the exercise.

The reason for the delayed soreness is that, in someone unaccustomed to eccentric exercise, it leads to localized areas of damage in muscle fibres. The present-day view is that the inflammatory response triggered by the damage leads to a sensitization of muscle nociceptors. For a review, see Proske & Morgan (2001). The soreness, referred to as delayed onset muscle soreness (DOMS), has a number of features that distinguish it from other forms of muscle pain. Incidentally, the accompanying sensation of muscle stiffness is the result of a damage-related rise in passive tension within the muscle (Whitehead et al. 2001). There is also some muscle swelling the day after the exercise. A characteristic feature of DOMS is that there is no chronic pain. So, on the morning after the exercise we feel fine, until we get out of bed and take the first few tottering steps.

Pain from DOMS can be evoked by muscle contraction, stretch and palpation, all mechanical stimuli that do not evoke any sensations of pain in an unexercised individual. It is for that reason it should be referred to as a tenderness, rather than a soreness. It has led to the view that DOMS is a type of hyperalgesia and is distinct from other kinds of muscle pain such as myositis, where there is typically some chronic pain associated with tonic activity in nociceptors (Berberich et al. 1988). Because of the unusual features of DOMS and because of the debilitating effects DOMS may have on the performance of competing athletes, there has been a need to find out more about the underlying neural mechanisms. Studying pain mechanisms in human subjects is fraught with difficulties, and only limited insight can ever be achieved, especially about central mechanisms. These are circumstances where animal models can play an important role.

Cattle Farming

Decreasing the fiber content of forages has been found to scale back methane production. Particularly, some legume forages are shown to decrease CH4 production, which has been explained by the presence of condensed tannins, low fiber content, high DM intake, and faster passage from rumen. Saponins, like China tree and Sesbania sesban, have potential to scale back CH4 production through an immediate effect on methanogen bacteria and protozoal number. Addition of 3–5% of the diet as tallow or oils has been found to decrease the methane production by 2–3%. Cattle production features a long history and milk production wasn't always the last word goal. Keeping cows and oxen for draughting purposes and for the production of natural manure was as important as for milk and beef production even in Europe till the mid of the twentieth century. This is the rationale that quite number of European breeds are well muscled and have sound feet and legs. Modern breeding programs combined with AI (AI) were applied in most of the breeds, improving milk yield and beef performance at an equivalent time. In Scandinavia, as well as in continental Europe, selection programs started around 1965 and replaced the former dominance of the show ring. Since these breeding programs are quite successful, many dual-purpose breeds still exist and are under active improvement. Farm size and price of land are another explanation for missing competition of beef breeds in most parts of Europe. Therefore, milk and beef are produced with the same breeds. This article also covers minor breeds, but it is impossible to describe all of them. References offer the possibility to go into further detail, and it should be mentioned that there are several activities to document the world cattle gene pool and also programs to conserve some of the original breeds.