In sheep breeders, the use of rams with high genetic merit is based on frequent use of insemination, either with fresh or especially with frozen semen. Orihuela et al. (2024) found that carbetocin, a synthetic oxytocin, applied prior to semen extraction through electro-ejaculation, allowed greater quantity and quality of semen to be obtained. For these reasons, we worked on two experiments using carbetocin prior to obtaining semen from rams through an artificial vagina. First experience was using 8 Texel rams outside the reproductive season and the second experience was using 24 rams, 12 Texel males and 12 Poll Dorset during the reproductive season. In both cases they were separated into two groups, one group received the administration of 0.002 mg/kg of carbetocin (D, Decomoton®, Calier, Argentina) intravenously 20 minutes before semen extraction and the other group remained as a control (C). The following week the treatments were reversed. Outside the reproductive season, a significant increase in sperm concentration (P = 0.01) and total sperm (P = 0.02) per ejaculate was seen, with a positive trend an increase in volume (P = 0.08). During the reproductive season, an increase was observed in both the volume (P = 0.02) and the proportion of live sperm (P = 0.01), allowing a greater quantity of total live sperm to be obtained (P = 0.01). In conclusion the use of intravenous carbetocin 20 minutes before semen extraction allows improving semen quality by increasing the number of doses for artificial insemination and semen cryopreservation.

While livestock production is a significant source of greenhouse gas emissions, it remains vital for fulfilling the growing global demand for animal protein. Including by-products in ruminant diets can enhance food circularity and reduce competition for human food, while also increasing the likelihood of reducing methane (CH₄) emissions. This study aimed to evaluate the impact of fully replacing corn grain and urea in the control diet with local by-products, specifically corn distillers’ grains combined with either barley brewed grains or with wheat middlings, on enteric CH₄ emissions and performance of sheep. Diets were balanced to be isoproteic and isoenergetic with 2.6 Mcal ME/kg of dry matter (DM) and 160 g crude protein/kg DM, respectively. Corn silage is the only source of forage in the diet, and the forage-to-concentrate ratio was maintained to 60:40 on a DM basis. Twelve Highlander female sheep of 35.9 ± 3.12 kg initial body weight (BW, mean ± standard deviation), were used in a Completely Randomized Block design, with four sheep per treatment and two measurement periods under the same treatment. Experiment lasted 60 d, 30 d acclimatization and 30 d measurements. Dry matter intake (DMI) was restricted to 2.5% of BW. Enteric CH₄ emissions of individual sheep were quantified in respiration chambers over a 48 h period. Dietary treatments did not have a significant effect either on DMI or BW gain. The diet containing barley brewed grains significantly reduced total daily CH₄ production by 22.3%, CH₄ emissions per kg of DMI by 34% and energy loss as CH₄ by 38% compared to the control diet. In conclusion, the agro-industrial by-products combinations evaluated in this study effectively replaced corn grain and urea without compromising feed intake or animal performance. Additionally, the diet containing barley brewed grains significantly reduced CH₄ yield, and energy loss compared to the control diet.