Breed, gender and seasonal variations of blood phagocytic activity in lambs from local sheep breeds reared in Bulgaria | Породни, сезонни и полови особености на фагоцитната активност при агнета от местни породи овце, отглеждани в България

The studies were performed in 2008 on 126 female and 90 male lambs. Investigations were carried out on 6 female and 6 male lambs from the breeds Karakachan, Tsigay, Copper-red Shoumen, Karnobat, Pleven Blackhead, Stara Zagora and Romanov at the age of 3, 6 and 9 months during the spring, summer and autumn. The phagocytic activity was determined via two parameters phagocytosis index - PI and phagocytic number - PN. PI was determined as a ratio of phagocytized leukocytes and the total leukocyte counts, multiplied by 100. PN was calculated as the number of bacteria, phagocytized by one leukocyte. It was found out that at the age of 3 months during the spring, the highest PI was exhibited by female lambs from the Stara Zagora– 82.00 - р 0.01 and Romanov breeds – 78.67%. In male lambs, the highest spring PI was determined in Tsigay - 80.67%; - р0.01 and Pleven Blackhead breeds - 79.67; р0.05, whereas the lowest – in Copper-red Shoumen male lambs– 75.33 %. At the age of 6 months during the summer, Tsigay female lambs had the highest PI - 81.00%, and Copper-red Shoumen – the lowest. Among studied male lambs, the highest PI was shown by Karakachan – 78.67% and Romanov breeds– 78.00%. During the autumn, 9-month-old female lambs from the Stara Zagora local breeds had the highest PI – 79.20. In males, the highest PI was that of Karakachan breed - 77.33 and the lowest – in Karnobat breed – 74.67. The spring phagocytic number was the highest in Romanov– 1.547, the lowest – in Pleven Blackhead female lambs - р 0.05. In general male lambs showed equal PN as females from the respective breeds – 1.499. During the summer, highest PN was observed in Karnobat female lambs - 1.493. During the autumn, the highest PN was measured in Romanov – 1.513, Stara Zagora– 1.512, Pleven Blackhead – 1.493, Copper-red Shoumen – 1.487 and Tsigay breeds – 1.453. The average PI for female lambs from all studied breeds was the highest in summer - 77.90 ± 1.873 with tendency to decrease in the autumn. In all studied male lambs, PI decrease in summer in autumn as compared to spring. In both genders, PN values were the highest in the spring at the age of 3-4 months, decreased in summer at the age of 6 months and increased insignificantly in the autumn.