Purpose: The aim of the research is to study the effect of subclinical ketosis (SCK) on the effectiveness of artificial insemination of highly productive dairy cows in the postpartum period.Materials and methods. The studied animals were selected according to the principle of conditional analogs and were divided into 2 groups of 6 animals each. Group 1 - animals with a blood concentration of 3- hydroxybutyrate˂ 1.0 mmol / l, group 2 - animals with subclinical ketosis with a concentration of 3-hydroxybutyrate in the blood in the range of 1.0-1.4 mmol / l. Blood was collected from animals on the 5th, 15th and 33-35th days after calving. In the obtained blood serum samples, the content of total protein, albumin, urea, glucose, cholesterol, triglycerides, calcium, phosphorus, magnesium, creatinine, total bilirubin, the activity of transaminase enzymes and alkaline phosphatase was determined. The concentration of steroid hormones has been determined. Before artificial insemination, the animals were synchronized according to the pressinovsinh scheme.Results. Most of the biochemical blood parameters did not go beyond the reference values. By the time of hormonal stimulation of sexual heat in cows with SCK, a decrease in 3-hydroxybutyrate (˂ 1,0 mmol / l) and an increase in glucose (> 3.0 mmol / l) were recorded. On the 15th day after calving, in the group with SCK, there was an increase in total bilirubin, cholesterol, triglycerides, and magnesium (p˂ 0,01). On the 15th day after calving, testosterone levels were 13% higher in the SCK group. By the time of synchronization, the level of progesterone in the group of animals with SCK was lower in comparison with the control group. In the group of animals with SCK, the lowest reproductive indices were recorded: the insemination index in the group with SSC was higher by 46%, the service period was 49 days longer, the interbody period was significantly longer by 68 days (p˂ 0,05).Conclusion. Subclinical ketosis, recorded on the 15th day after calving, helps to reduce the reproductive performance of high -yielding dairy cows. Normalization of the concentration of 3-hydroxybutyrate from subclinical to physiologically normal values, and subsequent hormonal synchronization do not reduce this negative effect of SCK.
The influence of the level of estradiol in the blood serum on the concentration of vitellogenin in Pushkin chickens at the end of the ovulatory cycle was studied. The results of the experiment show that in the studied chickens, the peak concentration of estradiol falls on the time interval between 7,5 and 2,5 h before egg laying (221,3±14,5 – 230,6±16,4 pg/ml, p<0,05) with subsequent its decrease (167,4±15,6 pg/ml). High correlation between the concentrations of estradiol and vitellogenin in the periods 9 h 00 min – 7 h 30 min and 2 h 29 min – 0 h 15 min before egg laying (r = +0,94 …+0,98, p<0,001), and also a significant relationship of estradiol with the weight of the yolk (r = +0,50 …+0,72), indicate that in these periods, the concentration of estradiol can predict the content of vitellogenin in the blood of chickens and the weight of the egg yolk. Accordingly, the concentration of estradiol can be used as a criterion for the selection of chickens on the basis of yolk size.
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