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Application of Immunological Control for Prognosis the Productivity of Karakul Sheep
The article provides recommendations on the use of immunological methods and criteria for assessing the level of natural resistance, in order to select animals with high natural resistance. Karakul sheep of the sur (brown) color having a concentration of common immune proteins of serum blood (CIPSB) with a quantitative method of 32–50 mg/ml and a semi–quantitative method of 1.1–2.0 conventional units, cellular immunity according to the skin reaction (delayed hypersensitivity reaction DHR) of 7.0–9.0 mm are classified as highly resistant; with CIPSB 18–31 mg/ml and 0.71–1.0 conv. units, DHR on a skin test of 5–6 mm to medium–resistant and respectively CIPSB of 13–17 mg/ml and 0.4–0.66 conv. units, DHR on a skin test of 3–4 mm and lower to a low–resistant group of animals. The indexes of common immune proteins of serum blood of 8–12 mg/ml and less according to the quantitative method and 0.25–0.45 conv. units according to the indicator method, T–cell activity according to the skin test of 1.0–2.0 mm characterize the immunodeficiency condition.
Studies have shown that the productivity of karakul sheep with a high level of natural resistance was higher than that of low–resistant ones. Karakul lambs with medium and high level of immunological reactivity quickly regained body weight after the stress factors of the weaning period, were better fed and weighed 33.6±0.45 and 34.5±0.35 kg at 8 months of age, the gain during the pasture fattening period was 8.2 ± 0.16 and 8.4± 0.11 kg, respectively, the average daily weight gain 91.1 g and 93.3 g, while animals with low immune reactivity weighed 30.3 ± 0.46 kg, where the gain over the entire period of pasture fattening was 6.7 ± 0.12 kg with an average daily gain of 74.4 g.
Body weight of lambs which suffered immunodeficiency conditions in various colostral–milk periods was 28.1 ± 0.75 kg, weight gain 6.2 kg ± 0.08 kg and average daily weight gain 68.8 g. The meat productivity (slaughter weight) of lambs with medium and high immune reactivity was 2.03 kg and 2.71 kg or 14.03 % and 17.9 % higher than in lambs with low natural resistance, and 3.24 kg and 3.92 kg or 22.4 % and 25.9 % higher compared to lambs which had immunodeficiency syndromes.