Sperm viability and morphology of two genetically diverse Merino lines

Abstract

Microscopically evaluated sperm parameters, as well as computer-aided sperm motility analysis (CASMA), were used to assess sperm quality and the effect of cryopreservation on ram semen obtained from two genetically diverse Merino lines. These lines were divergently selected on maternal ranking values for multiple rearing ability from the same base population since 1986. Replacements in the high (+) line were preferentially the progeny of ewes rearing >1 lamb per joining. Progeny of ewes rearing <1 lamb per joining was preferred as replacements in the low (–) line. Sperm quality, as assessed by percentages of live, abnormal and acrosome-intact spermatozoa as well as by motility, was independent (P≤0.20) of line, time of sampling and their interaction in ejaculated samples obtained from the eight rams used as sires in 1995. Sperm quality of frozen–thawed samples was adversely affected (P≤0.01) by cryopreservation and thawing at 35˚C for 30 s relative to fresh ejaculated samples. No consistent differences between lines were found in epididymal sperm samples obtained from 12 slaughtered rams (6 from each line). The adverse effect (P≤0.05) of cryopreservation and thawing at 35˚C for 30 s on sperm viability and motility was also demonstrated for these samples.

Improvement Strategies in Ovine Artificial Insemination

“…1998; Sancho et al. 1998), and others have analysed the effect of cryopreservation in sperm heads (Lambrechts et al. 2000).…”

“…The CASMA has allowed to detect morphometric differences in sperm head dimensions between fertile and subfertile males in some species such as stallion (Casey et al 1997). In ram, some studies have been carried out to develop accurate methods for employing CASMA of ram sperm heads (Gravance et al 1998;Sancho et al 1998), and others have analysed the effect of cryopreservation in sperm heads (Lambrechts et al 2000). The possible relationship between CASMA and fertility is still to be proved in this species.…”

Evaluation of morphological criteria of sperm quality before in vitro fertilization and intracytoplasmic sperm injection

“…Many authors using different staining methods describe various morphologic abnormalities of sperm in bulls (Revay et al 2009, Freneau et al 2010, Mandal et al 2010, Enciso et al 2011, stallions (Kavak et al 2004, Morrell et al 2008, Einarsson et al 2009, Brito et al 2011, Love 2011, rams (Lambrechts et al 2000, Janett et al 2001, Sweeney et al 2007, Lopez Armengol et al 2012) and dogs (Kawakami et al 2005, Nxñ ez-Martinez et al 2005, Peñ a et al 2007, Lange-Consiglio et al 2010). But we did not find concrete references what is the morphologically normal sperm cell in domestic animals.…”