Comparação de diferentes diluidores para o resfriamento de sêmen de carneiros deslanados criados no Sertão pernambucano

Abstract

Among the biotechniques applied to sheep reproduction, artificial insemination (AI) promotes greater impact on productive efficiency, due to its applicability and practicality, besides accelerating the genetic gain in the herd and controlling sanity more efficiently. The use of chilled semen may become viable to the producer since the material used and the procedures are more accessible, making possible the transport of genetic material between properties. For this purpose, semen extenders aim to improve the conservation of spermatozoa by making longer their viability outside the reproductive tract. Thus, the objective of the present study was to evaluate the technical viability of 4 extenders for the cooling of semen of rams raised in the backwoods of Pernambuco. Nine rams were subjected to semen collection and analysis, of which only 6 presented good semen traits for cooling. Ejaculates were divided into equal fractions and diluted with physiological saline, sucrose, skim milk and tris-egg yolk media, obtaining 30 million sperm/dose for each extender. The diluted samples were chilled in a refrigerator at 5 °C for 4 hours when they were then packed in ice-containing thermal boxes for transportation to the UAST chemistry laboratory. All samples were evaluated for motility, vigor and sperm morphology after 24, 48 and 72 hours of cooling. The tris-egg yolk extender was the only one able to keep sperm motile for at least 72 hours, but with motility and vigor appropriate for insemination for up to 48 hours. Moreover, such extender did not alter the sperm morphology, presenting good sperm preservation. One can conclude that the tris-egg yolk extender is technically feasible for the use and diffusion of artificial insemination in sheep raised in the backlands ofPernambuco.