Metabolic profiles and sperm production in imported Holstein bull sires under different climatic and geochemical conditions of Russia and Kazakhstan

Currently, the potential of highly productive animals adapted to industrial farming should be used most effectively and not depend on the geographical location and agro-climatic resources of the region. Our study showed that the observation of required technologies minimizes effects of regional climatic and geochemical factors. Our findings give more understanding on the metabolic peculiarities of the sire bulls in various geo-climatic conditions of the 55.86°N and 51.18°N zone. This may be of interest for the practice of breeding the Holstein breed in countries with similar geo-climatic factors. We compared the influence of climatic and geochemical conditions of the Central Russia (the Head Center for the Reproduction of Farm Animals, Moscow Province), the Middle Urals (JSC Ural-plemcenter, Sverdlovsk Province), and the Northern Kazakhstan (RCPZh JSC Asyl-Tulik, Akmola region) on the adaptive status of the imported Holstein 3-9-year-old bull sires ( n = 122). Blood levels of bioelements Ca, P, Mg, Ca:P, Fe, chlorides, Se, Cu, and Zn were recorded. To assess protein-lipid metabolism parameters and blood enzyme activity, the total protein, albumin, globulins, urea, creatinine, total bilirubin, urea, triglycerides, cholesterol, alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase were measured. The endogenous hormone levels (testosterone, estradiol, thyroxine, and cortisol) were measured. The volume of ejaculate, the concentration of spermatozoa in the ejaculate, and the number of spermatozoa in the ejaculate were assessed to evaluate sperm productivity. Climatic and geochemical characteristics of the regions were a temperate climate with sod-podzolic soils for the Moscow region, a sharply continental climate with bedrock rocks with sandy-clayey and sod-podzolic soils for the Middle Urals, and sever sharply continental climate with dark chestnut soil for the Northern Kazakhstan. The study revealed that the balance of macroelements was within the permissible limits and did not have significant differences between regions, i.e., 2.34-2.53 mmol/l Ca, 1.47-2.01 mmol/l P (Ca:P 1.20-1.65), and 0.79-0.98 mmol/l Mg. The iron supply in the Moscow region was within the normal range (23.82±6.18 μmol/l), reached the upper limits in the Northern Kazakhstan (30.74±6.97 μmol/l) and exceeded the physiological level (40.32±7.30 μmol/l) in the Middle Urals. The balance of Se (0.72-1.13 μmol/l) and Cu (12.6-16.0 μmol/l) was within allowed limits. On the soils of the Moskvoretsko-Oka geochemical province (the Head Center for the Reproduction of Farm Animals), the bulls were 65.8 % provided with Zn compared to 95.9 % provision (of that minimum allowed) observed in the dry steppe zone on dark chestnut soils of the Northern Kazakhstan. The enzymatic activity (as per the de Ritis coefficient) increased 2-fold in bulls of the Moscow region and the Northern Kazakhstan. All the sires had a sufficient concentration of both total protein and its fractions. The sires of the Moscow region fed an excessive amount of protein, as evidenced by the urea concentration at the upper limit (7.57±2.82 mmol/l) and creatinine 147.45±37.94 μmol/l). The bulls of the Northern Kazakhstan showed iron overload syndrome of 30.74±6.97 μmol/l with an increased bilirubin of 9.15±3.42 μmol/l. The balance of blood steroid hormones indicates a slight testosterone deficiency (39.17±5.06 nmol/l) and an excess of cortisol (226.75±45.62 nmol/l) in bulls of the Moscow region compared to the Middle Urals (50.36±5.80 and 138.81±21.48 nmol/l) and Kazakhstan (52.79±4.14 and 190.50±50.30 nmol/l); the differences are not statistically significant. The average level of blood thyroxine was within the physiologically permissible values, from 66.65±3.52 nmol/l in the Middle Urals to 91.13±3.35 and 95.39±1.86 nmol/l in the Moscow region and the Northern Kazakhstan, respectively. The level of estradiol varied from 0.197±0.02 nmol/l in the Moscow region to 0.234±0.02 and 0.276