Alternatives to time-consuming, laborious individual serving capacity tests (ISCT) are needed to classify ram sexual behavior. The objective of study 1 was to evaluate the relationship between the first 3-ram cohort test (COSCT) scores and the mean of 5 ISCT scores. The objective of study 2 was to determine whether 1 or 2 additional COSCT improved the ability to predict ISCT scores. For study 1...

Previous research has shown that the proportion of seasonal anoestrous ewes that ovulate in response to the introduction of rams ('ram effect') is dependent upon pheromonal and sexual behavioural stimuli emitted by the rams. Close contact with oestrous ewes is likely to increase the rams' libido and level of testosterone secretion, which in turn has been suggested to positively influence the pr...

The aim of this study was to determine whether advancing the seasonal changes associated with rams by treatment with exogenous melatonin and allowing the rams previous sexual experience would increase the proportion of anoestrous ewes ovulating in early July. North Country Mule ewes (n = 225) were grouped by live body weight and body condition score and allocated randomly to the following treat...

Thirteen Targhee rams selected for rate and efficiency of gain for 4 yr (1.5 generations) were compared with 10 rams from a Targhee line with no selection for over 20 yr to determine if selection for these traits would be associated with changes in the secretion of growth hormone (GH), thyrotropin (TSH) and(or) prolactin (PRL). Selected rams exhibited greater birth weight, average daily gain (A...

Five Chios and five Friesian rams were used to study the effect of season on semen production. Semen samples were collected with an artificial vagina. In spite of the large variation of most of the semen characteristics among rams of the two breeds, seasonal variation in semen quantity (volume, concentration and total number of spermatozoa per ejaculate) and quality (percentage of motile sperma...

The Register of Antarctic Marine Species (RAMS) is a marine species database that manages an authoritative taxonomic list of species occurring in the Southern Ocean. RAMS links with several other initiatives managing biogeographic or genomics information. The current paper aims to briefly present RAMS and provides an updated snapshot of its contents, in the form of a DarwinCore checklist (avail...

We evaluated sexual behavior of St. Croix White (SC; n = 5) and Barbados Blackbelly hair (BB; n = 4) rams under two environmental conditions in the tropics. Sexually naive rams were individually exposed for 15 min to a restrained, ovariectomized ewe, three times during a 3-wk period in June, in a pen with shade (SHADE; 33.1+/-.3 degrees C) or without shade (SUN; 38.3+/-.3 degrees C). Rectal tem...

The first objective of this study was to determine whether LH and testosterone respond differently to a naloxone injection in relation to varying sexual performance in rams. If differences occurred, the second objective was to determine whether differences would predict variation in sexual performance. From a group of 1.5- to 3-yr-old rams, 20 sexually active and 39 sexually inactive rams were ...

Surgically induced cryptorchidism in rams resulted in elevated serum concentrations of LH but near-normal concentrations of androgen (testosterone and 5 alpha-DHT). Injections of ovine LH (2 X 50 microgram; 2 X 500 microgram) resulted in maximal androgen secretion in the intact rams and similar but lower concentrations in cryptorchid rams. Peak concentrations were 14.9 and 8.5 ng/ml in the inta...

rams once every 4 hr was shorter when ewes and rams remained together than when they were kept apart between observations. Continuous contact with rams appeared to limit the duration ofoestrus by inhibiting the neural mechanism controlling the expression of oestrous behaviour. Second, the duration of oestrus measured by teasing ewes individually every 4 hr and keeping them with rams between obs...