Тhe content of calcium and phosphorus in the blood of cows with a different tonus of the autonomic nervous system

Abstract

Research was conducted on cows of the Ukrainian black-and-white breed of the 2–3 lactation. Tonus of the autonomic nervous system (ANS) of cows was determined using trigeminovagal reflex (TVR). According to the obtained results, an animal was designate as normotonics, sympatheticotoniсs or vagotonics. According to the results of the study of the ANS tonus, 3 experimental groups were formed 4 animals in each. The first group included animals-normotonics, the second – vagotonics, and the third one – sympatheticontics. It was established a tendency of сalcium/hosphorus lower content in the blood of cows during the warm season and higher in the winter (in the range of 3–8%). It should also be noted that there was tendency towards lower calcium content in the blood of vagotonic cows and higher – in sympatheticotoniс animals, regardless of the season. Unlike calcium, the content of phosphorus in the blood of cows significantly depended on the ANS tonus. In particular, the content of this element in the blood of sympatheticotoniс and vagotonic cows in winter was lower by 14.0% (P < 0.001) and 18.3% (P < 0.001), respectively. However, in the summer, this difference became significantly smaller and had character of a trend (at the level of 5.0–7.2%). It has been established that the calcium-phosphorus ratio in cow’s blood did not depend significantly on the ANS tonus or on the season of the year, but a clear trend was established for its lower value in summer, regardless of the ANS tonus. The strength of excitability levels of the sympathetic and parasympathetic nervous system according to the results of the TVR in cows did not significantly limit the phosphorus content in their blood in summer, and calcium in winter (η2x = 0.00–0.019). But in normotonic animals, the ANS tonus significantly affected the calcium-phosphorus ratio – η2x = 0.59 (P < 0.05) and the phosphorus content in their blood – η2x = 0.29 (P < 0.05) in winter. It was established that ANS tonus in sympatheticotonic animals limited the phosphorus content in winter – η2x = 0.35 (P < 0.05) and the calcium-phosphorus ratio as in summer – η2x = 0.29 (P < 0.05) so in winter – η2x = 0.45 (P < 0.05). Whereas in vagotonic cows, the ANS tonus limited the calcium content in the summer – η2x = 0.26 (P < 0.05). Correlation analysis of the ANS tonus index, phosphorus and calcium content in cow’s blood did not establish significant interrelationships depending on the season of the year. However, it should be noted a clear trend of direct correlation of the index of the ANS tonus with the calcium content (r = 0.24–0.35) and the calcium-phosphorus ratio (r = 0.43–44) in the cows’ blood and the reverse one with the phosphorus content in the cows’ blood (r = -0.22–0.30). The data obtained could indicate on the presence of autonomic regulatory mechanisms for the regulation of the content of specific macronutrients in the blood of cows.