Metabolism Essay

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Metabolism is extremely altered during the transition period. The prepartum is marked by an accentuated fetus growth (Bauman and Bruce Currie, 1980) and the onset of lactation; however, the postpartum is marked by an increase in milk production over time and deficit on the intake of nutrients. This situation causes a negative balance of nutrients, when the intake of nutrients does not meet the requirements of the animal; more specifically about energy, it is well-known that transition cows undergo negative energy balance (NEB), and it is easily characterized by body weight (BW) and body condition score (BCS) loss. Bertics et al., 1992, and Hayirli et al., 2002, observed that DMI is affected during the prepartum period, showing a decrease of about 30% on the last couple weeks before parturition. After parturition, DMI increases to support mainly the demands for lactation but it is still not enough to meet the animal demands (NRC, 2001). DMI is directly related to milk yield and strategies have been developed to maximize intake in order to increase milk production, this shows its importance by the fact of an increase of about 1 kg on milk production at peak of lactation reflects about 200 kg of extra milk on the current lactation. Providing quality feed and maximizing DMI during the transition period is of high importance in minimizing NEB and its detrimental effects consequently improving milk production. Metabolic demands are increased to support lactation, and homeorhetic adaptations occur to partition nutrients to the mammary gland. A good example it is the glucose metabolism, an important metabolite used as main fuel for cells and also transformed in lactose by the mammary gland, which is affected in order of trying to meet th...

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... whey antibody. The release of stored cells and activation of the colony-stimulating factors by the bone marrow in response to recombinant bovine somatotropin (bST) increased proliferative responses to leukocytes (Burvenich et al., 1999). At the farm level, Eppard et al. (1996) administered bST to periparturient cows and found that the incidence of clinical mastitis was decreased. Based on these findings it is suggestive that GH is an important factor for strengthening the immune system around this time.
The incidence of mastitis is associated with impaired PMN function (Cai et al., 1994) since the resolution of the disease is dependent on the ability of PMN for recognition of the pathogen, migration to the site of infection, phagocytic ability and its elimination (Vangroenweghe et al., 2005), and dependable of the generation of ROS by PMN (Heyneman et al., 1990).

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