Metabolic status of the cows under intrauterine growth retardation of embryo and fetus

Intrauterine growth retardation of embryo and fetus (IUGR) in cows is a polyfactorial syndrome which is defined as an inconsistency between the sizes of forming embryos and fetuses and gestation periods. It is thought that the processes of embryo and fetus growth and development in cows are determined by morphofunctional integrity of gametes entering into the process of insemination and are mainly regulated by the character of maternal nutrition, state of metabolic homeostasis and maternal genitals. This work was devoted to the study of cows' metabolic status under intrauterine growth retardation of embryo and fetus. In 2013 at a large dairy complex (Agrotekh-Garant Ltd. Nashchekino, Anninskii Region, Voronezh Province) a total of 53 Red-motley Holstein cows with average annual productivity of 6.0-6.5 thousand kg were studied for protein metabolism indices (content of total proteins, protein fractions, serum urea), carbohydrates (blood concentration of glucose, lactic and pyruvic acids), vitamins (A, E, C), hormonal homeostasis (blood serum content of progesterone, dehydroepiandrosterone sulfate, testosterone, estradiol, cortisol, triiodothyronine), endogenous intoxication (concentration of middle molecular peptides, urea, creatinine, transaminase blood serum activity) and nitric oxide system on the days 38-40, 60-65, 110-115 and 230-240 of gestation. The impact of these indices on the development of embryo and fetus was also studied. Blood was collected from the jugular vein in the morning before feeding. The evaluation of genitals and metrics of embryo and fetus were done by the method of transrectal palpation and sonography with the use of bovine ultrasound scanner Easi-Scan-3 with 4.5-8.5 MHz linear transducer (BCF Technology Ltd, United Kingdom). The diameter of the fertilized horn, placenta size, body diameter and coccyx-parietal size of the fetus were determined. Coccyx-parietal size of 12-16 mm and body diameter of 7-9 mm were the criteria of development at the age of 38-40 days, 25-45 mm and 12-16 mm - at the age of 60-65 days, respectively. The diameter of the fertilized horn of 9-15 cm and placenta of 10-17 mm were the criteria of development at the age of 110-115 days. The animals with IUGR, diagnosed during 38-40 days of gestation, were included into the experiment on the days 230-240. It is stated that during early stages of fetus formation (38-40 days) the retardation of its growth and development is connected with hypoprogesteronemia determined by hypoplasia of the yellow body. The cows with IUGR also demonstrated blood serum decrease of cortisol by 36.9 % (p < 0.01) and increase of triiodothyronine by 35.4 % (p < 0.005) in comparison with the animals with physiological gestation course that proves total hormonal imbalance. At the stage of placentation (60-65 days) the cows with IUGR demonstrated evident deficit of nitric oxide that was proved by the decrease of its stable metabolite concentration (NO2- + NO3-) in blood serum by 23.9 % (p < 0.05) in comparison with the level of the cows with physiological gestation. Authentic decrease of vitamin C content in blood serum, increase of middle molecular peptides level and activity of γ-glutamyl transferase by 42.9-51.0 %, 32.6-67.7 % and 22.1-54.0 % (p < 0.01), respectively, in comparison with the animals with physiological gestation were observed in cows with IUGR throughout the research. The article discusses the role of metabolic disorders in pathogenesis of intrauterine growth retardation of embryo and fetus in cows.