Suchergebnisse

The high mortality rates of calves has encouraged research of the physiological mechanisms that control birth and adaptation of newborns to extrauterine life, to allow early identification of the presence of disease characteristics during the neonatal period. This study aimed to determine the occurrence of anemia in Holstein calves in the first month after birth and address the lack of information on the subject in neonates raised under national conditions. In total, 385 animals, 199 from refrigerated type A raw milk producing and 186 from refrigerated raw milk producing dairy farms, were surveyed. Anemia was observed in 14.3 % of the heifers (55/385), with a higher frequency in the farms producing type A milk (18.6 %, 37/199). It was concluded that the frequency of anemia is significant in neonates of the studied breed, particularly in those with more technified properties (type A milk), with this condition being, in most cases, a possible etiology of iron-deficiency.

Sucrose- and diuretics-based protocols are widely used to induce osmotic diarrhea and dehydration in calves, but they fail to cause metabolic acidosis. In previous studies, calves were fed milk replacers and deprived of water. In this study, we assessed the water, electrolyte, and acid-base imbalances in calves that were fed whole milk and were not completely deprived of water during the induction period. Healthy, male Holstein calves aged 10-12 days were assigned to two groups: free access to water (FWG; n=17) and water deprivation at night (DWG; n=21); and osmotic diarrhea was induced with sucrose added to milk, spironolactone (2mg kg-1) and hydrochlorothiazide (2mg kg-1) orally every 8h for 48h. pH, pCO2, HCO3-, BE, Na+, K+, Cl-, SID3, TPP, AG, Atot, glucose, L-lactate, D-lactate, SIG, and percentage change in plasma volume were measured in venous blood samples taken at 0, 24, and 48h. Data were analyzed using two-way repeated measures ANOVA. Calves showed diarrhea, mild (FWG) to moderate (DWG) dehydration, hyponatremia, and moderate (FWG) to severe (DWG) metabolic acidosis. AG and D-lactate levels were higher and SIG was lower in the DWG, and there was no hyper-L- or D-lactatemia. The magnitude of metabolic acidosis was similar to that observed in natural cases of diarrhea. The protocol for inducing osmotic diarrhea and dehydration should be applied to calves that are fed whole milk and are not completely deprived of water.