Evaluation of blood minerals and oxidative stress changing pattern in prepartum and postpartum Achai and Holstein Friesian dairy cows.

This research focused on evaluating blood mineral levels and malondialdehyde (MDA) as an indicator of oxidative stress before and after giving birth in Achai and Holstein Friesian (HF) dairy cows. Blood samples were obtained from a total of 50 cows representing both breeds on the third, second, and first week prior to calving, as well as on the day of calving (day 0). Subsequently, samples were collected on the 1-3 weeks postpartum to allow a comprehensive evaluation of blood parameters throughout the peripartum period. Results showed a significant (p < .01) decrease in serum zinc (Zn) levels on the day of parturition in both breeds. Additionally, HF cows exhibited higher (p < .01) Zn levels on week 2 before giving birth. Interestingly, blood selenium (Se) concentration increased (p < .01) in HF cows on weeks 2 and 3 after calving. In contrast, Achai cows showed a rise (p < .01) in blood Se on week 3 of parturition. Blood copper (Cu) levels were higher (p < .01) on weeks 2 and 3 after parturition in HF cows and on third week before parturition compared to Achai cows, where serum Cu remained high on week 1 of parturition. The findings indicated that blood magnesium (Mg) was higher (p < .01) on third week before parturition in Achai cows and on weeks 2 and 3 after parturition. Serum calcium (Ca) was higher (p < .01) in both HF and Achai cows on weeks 2 and 3 after parturition, and lower (p < .01) on third week before giving birth in both breeds. The mean blood MDA levels in Achai cows were lower (p < .01) on weeks 1 to 3 postpartum or 3 weeks before giving birth. In HF cows, serum MDA increased (p < .01) just before 2 weeks of parturition and remained elevated until 3 weeks of parturition. Thus, both breeds exhibited a similar pattern of mineral fluctuations; yet, Achai cows demonstrated greater resilience to oxidative stress compared to HF cows during the transition period.

Avaliação física e dos níveis séricos de cortisol de bezerros neonatos da raça Nelore, nascidos de partos normais e auxiliados / Physical and serum cortisol levels evaluation of Nelore newborn calves born by normal and laborious parturition

O presente trabalho visou avaliar a vitalidade e os níveis séricos de cortisol de bezerros neonatos, nascidos de partos eutócicos e auxiliados, bem como determinar os índices de partos distócicos em vacas receptoras de embriões nelores. Cerca de 310 bezerros foram avaliados. Observou-se a ocorrência de 38 partos distócicos (38/310) e de oito abortos (8/310). Os bezerros nascidos de partos distócicos mais duradouros, entre quatro e seis horas, apresentaram os maiores valores médios de frequência respiratória e dos níveis séricos de cortisol. A temperatura retal foi mais elevada em animais nascidos de partos laboriosos do que naqueles nascidos de partos normais. As taxas de morbidade e mortalidade em animais neonatos nelores foram de 77,93 por cento e 3,44 por cento, respectivamente. O emprego do escore APGAR, ao nascimento, demonstrou que 90 por cento dos bezerros apresentavam-se deprimidos, independente do tipo de nascimento.

The purpose of present study was to evaluate the vitality and the serum levels of cortisol from newborn calves by normal and laborious deliveries, and to obtain the distocia register in Nelore embryo recipient cows. Three hundred ten calves were evaluated. The register of 38 dystocic calvings (38/310) and 8 abortions (8/310) were observed. In newborn animals the morbity and mortality rates were 77.93 percent and 3.44 percent, respectively. Calves born after long dystocic calving, lasting 4-6 hours, showed the highest mean values of respiratory frequency and serum cortisol levels. Animals born after laborious calving presented higher rectal temperature than those born at normal calving. The APGAR score showed that 90 percent calves had signs of dullness independent of parturition type.

Energy metabolism and thermoregulation in the newborn calf.

About half of calf losses occur during the first two days of life. Mortality rate is increased by difficult parturition and adverse climatic conditions. However, thermoregulatory mechanisms are operative at birth, these including the metabolism of brown adipose tissue, shivering and physical activity. Thermoregulation is just as effective in twin as in single calves provided that calving conditions are good. Heat production of Charolais and Salers calves was lower than that of Friesian; the difference came from a lower basal metabolic rate rather from a better thermic insulation. In dystocial calves, blood pH at birth was very low, lactataemia was two or three times higher than in eutocial calves, mobilization of body lipids was reduced and plasma thyroïd hormone level were low, which can explain the lower heat production and the drop in rectal temperature. The physiological responses of calves born by caesarean parturition depend on the delay incurred during surgical removal.

A critical review of current methods for induction of parturition in the mare.

The efficacy and safety of oxytocin, dexamethasone and prostaglandin, used alone or in combination as inducing agents, are discussed. It is contended that insufficient evidence exists to support the routine application of any of these methods in practice. Oxytocin has been the most widely used and it is claimed by some to be free from side effects. However, the synthetic prostaglandin analogue, fluprostenol, seems to pose the least risk to the foetus and dexamethasone appears to be either ineffective, or too dangerous to use at all. The main indications for induced foaling are managerial convenience or for research and teaching purposes. There are few clinical indications, although ventral rupture and cases of prolonged gestation have been mentioned by various workers. It is considered that foetal maturity is the pre-requisite before a decision to induce should be made in practice, and 3 criteria are essential: 1) a gestational length of greater than 320 days, 2) substantial mammary development, 3) the presence of colostrum in the mammae.