In vitro assessment of sperm quality from rams of high and low field fertility.

The aim of the present study was to investigate whether differences in field fertility of rams are reflected in differences in several sperm quality parameters. Ejaculates from 8 adult rams, 4 with high and 4 with low field fertility, were collected weekly using an artificial vagina over 6 consecutive weeks. Analyses of sperm motility by computer-assisted sperm analysis (CASA), membrane integrity by acridine orange-propidium iodide combination and sperm DNA fragmentation using the sperm chromatin dispersion test (SCD) were performed at 0, 3, 6 and 24h of incubation at 37°C.

Factors affecting fertility after cervical insemination with cooled semen in meat sheep.

Field results of 18,328 cervical artificial inseminations (AI) with cooled semen in Rasa Aragonesa meat sheep under field conditions in north-eastern Spain AI were analyzed. Logistic regression procedures were used including fertility at AI as the dependent variable (measured by lambing, 0 or 1) and year, month of AI, farm, hours between extraction and insemination, number of ewes inseminated in a set of AI, parity, lambing-treatment interval, total number of synchronization treatment per ewe, inseminating ram and AI technician as independent factors. Previous parturitions, lambing-AI interval, month, farm, inseminating ram and technician were factors with significant impact on AI fertility.