Values of plasma lipid hydroperoxides and total antioxidant status in healthy dairy cows: preliminary observations

Abstract

Metabolic parameters have been used in an attempt to monitor the health, reproductive and nutritional status of dairy cows. Nevertheless, in the last few years the detection of free radical damage, and the protection against it has become very important in the practice of clinical medicine. This report aims to establish values for plasma lipid hydroperoxides (LOOH) and total antioxidant status (TAS) in healthy cows and its relationship with milk yield. The study was carried out with 22 healthy dairy cows divided into two groups: animals with a low production rate and animals with a high milk yield. Results showed that the animals with a high milk yield present higher LOOH levels than the other group. This increase in oxidant compounds is not accompanied by higher levels in protective antioxidant substances. LOOH and TAS measurements give complementary information about the metabolic status of the animal than metabolic parameters alone.

Evaluation of blood and milk oxidative status during early postpartum of dairy cows

“…This implied that also the plasmatic a-toc levels in the calves of multiparous cows after birth were significantly higher, probably because of a higher a-toc transfer via placenta or a-toc secretion in the colostrum. Castillo et al (2005) reported that TAS obtained in late lactation and pregnant cows was lower than the one observed in a previous report on dairy cows at their lactation peak (Castillo et al, 2003), and these results were in agreement with Wachter et al (1999), which observed a progressive decline in antioxidant activity as lactation progresses, probably because of the depletion of fat-soluble antioxidants by milk.…”

“…Our results, considered in the light of the available literature by Wachter et al (1999) and Castillo et al (2003), show a progressive decrease of serum antioxidants in Brown cows with the progress of lactation (from the 12th to the 16th day postpartum), probably because of the depletion of fat-soluble antioxidants by milk.…”

“…This implied that also the plasmatic a-toc levels in the calves of multiparous cows after birth were significantly higher, probably because of a higher a-toc transfer via placenta or a-toc secretion in the colostrum. Castillo et al (2005) reported that TAS obtained in late lactation and pregnant cows was lower than the one observed in a previous report on dairy cows at their lactation peak (Castillo et al, 2003), and these results were in agreement with Wachter et al (1999), which observed a progressive decline in antioxidant activity as lactation progresses, probably because of the depletion of fat-soluble antioxidants by milk.On the other hand, Castillo et al (2006) reported that the metabolic adaptation to the onset of lactation leads to an overproduction of free radicals, which cause lipid peroxidation and high MDA values. However, in this period, the antioxidant system can cope with this condition effectively, whereas the achievement of peak of lactation is accompanied by a stabilization of the metabolic status that is reflected by a stabilization of the antioxidant status as well.…”

Effect of some factors on relationships between milk urea levels and cow fertility

“…In milk, urea nitrogen forms 2.5-3 % of total nitrogen (Melendez et al 2000). Several experiments (Hamann & Kromker 1997, Skrzypek 1998, Castillo et al 2003 showed that in terms of nutrition, the optimum milk urea concentration for large dairy breed cows is 15-30 mg/dl. Monitoring blood or milk urea content may help to identify reasons for reproductive failure or health disorders (Markiewicz 2003).…”

“…Because of passive diffusion, the urea molecule regulates concentrations of body fluids, and serum and milk urea levels are positively and highly correlated (Butler et al 1996, Castillo et al 2003. In milk, urea nitrogen forms 2.5-3 % of total nitrogen (Melendez et al 2000).…”