amount of energy needed to synthesise 0.6 kg/d of milk. The effect of fats on methane production may, however, vary de- pending on the fat source (Table 1), and maybe attributed to the bio-hydrogenation of unsaturated fatty acids in the rumen, promotion of propionic acid production, and prevention of protozoa activity. The high grain diets can promote an over- growth of Clostridium perfringens, bacteria associated with the sudden death syndrome in feedlot cattle. These diets may fur- ther promote E-coli within the digestive tract of cattle and hence cause harm to the animal. With high grain diets, saliva production is reduced and the rumen pH may drop to a level that is associated with the occurrence of acidosis. In this latter case, it is recommended to increase the proportion of the for- age fed during particularly cold weather, as the effects of aci- dosis are worsened if the animal is also suffering from cold stress.
4. Grazing management In most grazing conditions, gastrointestinal parasitism may develop through the establishment of a physiological associ- ation between the parasites and their host animals. The inter- nal parasite residing in the true stomach (abomasum) such as H. contortus and O. ostertagia may cause damages to the HCL-secreting glands. As a result, the pH level in the gastric liquors increases to about 7 or more, which leads to increased production of gastrin hormone in the stomach, thereby in- creasing the secretion of water from the liver, pancreas, and the distal part of the small intestines and – in turn – causes diarrhoea and weight loss. The internal parasites residing in the small intestines such as
Table-1- Effect of fat source on methane production in the rumen.
Fat Source Soybean oil Coconut oil Palm oil Garlic oil
Linseed oil Clove oil
Peppermint oil Source: N. N. Toprak, 2015
Table 2 – Parasite burden in sheep grazed after cattle (group A) vs. grazing after sheep (group B).
Ostertagia spp. Adapted from Smith and Archibald (1969). References available on request 114 ▶ GUT HEALTH | DECEMBER 2020 Cooperia spp.
A 573 31 B
N. Spathiger 101
935 141 468
Methane production -22% -33% -29% -42% -57% -34% -25%
T. colubriformis cause atrophy of the intestinal villi and hence reduces their ability to increase the surface area available for absorption and utilization of feeds. In extreme cases, these parasites may cause damages to the intestinal wall itself and hence allow for the passage of the immunoglobulins from the blood plasma to the gastric cavity with an eventual loss of these immunoglobulins through faecal excretion and a de- creased resistance of animals to the microbial diseases. When adopting mixed grazing, the stocking rate for each spe- cies is lower, thus reducing the overall degree of contamina- tion. Here, it was found that the numbers of eggs from intes- tinal parasites in droppings from lambs were 492 and 198 for single and mixed grazing, respectively. It was also found that the numbers of infective larvae per kg grass in a given season were 235, 178, and 97 for the cattle areas, sheep areas, and the mixed areas, respectively. The cross-immunity between cattle and sheep is also a mech- anism by which mixed grazing helps control gastrointestinal parasites. The intake by sheep of larvae from the bovine ori- gin is not only ineffective in sheep because of the host speci- ficity, but also stimulates immunity in sheep to challenge with their own parasite species (Table 2). Such resistance was also found in cattle, but to a less extent, as a result of the in- take of larvae from the ovine origin. In either case, the com- plete recovery from the gastrointestinal parasitism may not be expected through the grazing system alone. The use of an- thelmintics should also be considered for better control of the parasite problem. This latter measurement would, howev- er, be more effective and economical when considered along with mixed grazing.
5. Colostrum feeding of calves Colostrum should be fed in adequate amounts (10% of calf body weight) within the first 24 hours after birth. After pro- viding adequate colostrum on day one, a second dose should be fed (especially useful in stressed calves). The im- munoglobulins in colostrum will coat the small intestine and prevent attachment and colonisation by pathogens. Additionally, colostrum provides an excellent source of en- ergy and contains compounds such as lactoferrin and fatty acids that benefit the calf.
Conclusion Under confined feeding operations, cattle should receive suf- ficient amounts of protein fat and fibres with controlled amounts of grain to maintain gut integrity and minimise the proliferation of GI pathogens. Mixed grazing should be adopted as it helps control GI parasites through the cross-im- munity. For control of the gut health of calves, colostrum should be given immediately after calving. This would pro- vide the antibodies needed to fight against the GI pathogens.
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