The relationship of body condition indicators with the level of plasma cocaine and amphetamine regulated transcript and energy metabolism indicators in dairy cows

The factors affecting the course of lactation and intensity of milk secretion include the condition and body weight, as well as chewing time. A little researched factor is also the cocaine and amphetamine regulated transcript (CART) which has been suggested to have an anorexigenic function. This study sought to examine the dependent indicators of condition and chewing time on daily milk yield assessment in the context of the concentration of CART, glucose and ß-hydroxybutyrate (BHB) in blood. Higher CART levels contributed to shorter chewing time (min/day), lower body condition and lower body weight. Blood glucose concentration showed a stronger correlation with body weight and condition than with blood BHB concentration. An important practical aspect of the results is the relationship shown between CART and chewing time and the potential relation between daily milk production and chewing time. Importantly, the animals with lower daily milk production had relatively the highest concentration CART. This may suggest that this neuropeptide is indirectly involved in milk production, especially by shortening the chewing time. The obtained results help to better explain the mechanisms involved in milk secretion and the process of rumination and digestion. More research is required, but they also show important functions of other examined neuropeptides.

Correlation between the cocaine- and amphetamine-regulated transcript in the pyloric section of the abomasum and fat deposition in bulls’ carcasses

The study was aimed at investigating the relationship between the number of cocaine- and amphetamine-regulated transcript (CART) structures present in the pyloric section of the abomasum and fat accumulation in carcasses of bulls – crosses of Polish Lowland Black-and-White cows mated with Limousin bulls. The bulls were slaughtered at the mean age of 629 days and body weight of 597 kg. The distribution of cocaine- and amphetamine-regulated transcript-immunoreactive in the pyloric section of abomasum was assessed on the basis of CART positive immunohistochemical reactions. Significant interdependence was found between the number of CART structures and carcass adiposity and the fat content of the longissimus lumborum muscle. The identified tendency for fat tissue increase in the carcasses was accompanied by a lower concentration of the structures. In the endocrine system cell the greatest number of immunopositive cells were found; ranging from 28.9 in animals more obese to 37.8 with the smallest amount of fat accumulated. The lowest numbers of immunopositive cells, ranging from 2.4 to 3.9 were noted in the submucous plexus layer. Slightly more structures were observed in nerve fibres and the myenteric plexus, at 2.9 and 4.7, respectively. The number of CART in the endocrine system was correlated with subcutaneous fat (-0.451) and marbling (-0.514). The amount of CART in these anatomical layers was significantly correlated with the thickness of subcutaneous fat (-0.541 and -0.636) and the weight of perinephric fat (-0.487 and -0.672). The results confirm that CART is an important neurotransmitter that participates in the regulation of fat deposition in the body. It must be stressed that the correlations with the analysed fat deposition indices concerned the adiposity indicators influencing the commercial value of carcasses and the meat traits important to the consumer.