The objective of this study was to evaluate the inclusion of oregano essential oil (OEO) as a phytogenic feed additive in the diet of lambs on the productive performance, ruminal pH, ammoniacal nitrogen production, volatile fatty acids, nitrogen balance, carcass yield, backfat thickness, loin eye (Longissimus dorsi) area, shelf life, and antioxidant activity of the meat. Thirty-nine Suffolk × Hampshire lambs (19 ± 3.7 kg live weight) were used in a completely randomized design with three treatments (n = 13) consisting of 0, 0.02, and 0.04% OEO in the diet. The inclusion of OEO in the diet did not affect (p > 0.05) the productive performance due to the treatments; similarly, no differences (p > 0.05) were observed in the ruminal variables and nitrogen balance. Backfat thickness and loin eye area had similar results (p > 0.05), and the antioxidant activity in meat was improved (p < 0.05) with the inclusion of OEO. Shelf life and crude protein content increased (p < 0.05) with the inclusion of OEO in the diet and with the passing of storage days. Dry matter was affected (p < 0.05) by the storage time, with a decrease observed on day 24. pH, ether extract, and ash were not affected (p > 0.05). It is concluded that the productive performance, ruminal variables, nitrogen balance, loin eye area, backfat thickness, and carcass yield were not affected by the inclusion of OEO. However, crude protein remained stable and antioxidant activity improved, increasing the shelf life of lamb meat.

This study aimed to evaluate and compare the effects of HS on sow reproductive performance using 11 different thermal indices calculated from environmental data in a temperate climate. Reproductive records, including live-born piglets, stillbirths, and mummified fetuses per litter, were obtained using farm management software. The overall means for live-born piglets, stillbirths, and mummified fetuses per litter from January to December 2023 were 13.7, 1.06, and 0.45, respectively, whereas the temperature, relative humidity, and air velocity were 24.08 °C, 63.70%, and 3.2 m/s, respectively. Temperature–humidity index (THI): THI2 and THI6 were significantly associated with the number of live-born piglets (p < 0.001) and mummified fetuses (p < 0.05) per litter, with optimal reproductive outcomes observed at values below 74. THI1 was significantly associated with the number of stillborn piglets (p < 0.05). Based on the Akaike information criterion (AIC) values, THI6 provided the best overall fit for evaluating the effects of HS on reproductive performance. Reproductive outcomes in sows respond to trait-specific thermal signals. THI2, THI6, and THI1 are recommended for assessing HS-related reproductive outcomes in sows raised under temperate climatic conditions.

The objective of this study was to evaluate the productive performance, ruminal fermentation, in vivo digestibility, carcass yield, and physicochemical variables of meat when bovine rumen content (BRC) was included in the diet of lambs. Thirty-six Pelibuey-Dorper crossbred lambs of both sexes, with an average weight of 19.5 ± 1.5 kg, were used in a generalized randomized block design with the sex of the lambs as a blocking factor with four treatments: BRC₀, BRC₁₅, BRC₃₀, and BRC₄₅, corresponding to 0%, 15%, 30%, and 45% BRC inclusion in the diet, respectively. The results indicate that the dietary effect was not significant for any of the evaluated variables, whereas sex showed significant differences in final body weight, average daily gain, dry matter intake, and hot and cold carcass yield. Although specific treatment-sex combinations significantly influenced productive performance variables such as average daily gain, dry matter intake and ruminal fermentation parameters, such as propionic acid, there is no consistent evidence that the inclusion of bovine rumen content promotes superior productive performance or carcass quality in fattening lambs.

Background. Ruminants have been related to greenhouse gas production. Therefore, it has been necessary to find alternatives by using natural additives to reduce their production by modulation of rumen fermentation. Objective. It was to evaluate the effect of the addition of condensed tannins (CT) and different levels of essential oregano oil (Lippia graveolens) (EOO) in sheep's diets on in vitro fermentation products such as total gas production, methane (CH4), carbon dioxide (CO2), pH, ammoniacal nitrogen (N-NH3), and volatile fatty acids (VFA). Methodology. There were evaluated six experimental diets: the control diet with 4% of CT kg/DM, and 0.02, 0.04, 0.06, 0.08 or 1% de EOO kg/DM, respectively. Total gas production, CH4, CO2, pH, N-NH3, and AGV were measured at different in vitro incubation times. Results. Total gas production was not affected (P > 0.05) due to treatment or the interaction treatment*time. An exponential increment was observed (P < 0.05) according to incubation time. CH4 and CO2 production increased at 48 h. The lowest emissions of these gases were recorded when 0.04, 0.06, 0.08, and 1% of EOO were added to the diet. Nevertheless, no differences were found (P > 0.05) due to treatment or the interaction treatment*time. Acetic and butyric acid concentrations were affected due to incubation time and the interaction treatment*time; however, there was no effect due to treatment (P > 0.05). Propionic acid production and pH were not affected (P > 0.05) due to treatment, time, or interaction treatment*time. N-NH3 production increased through incubation time (P < 0.05), with the highest concentration at 48 h for all treatments, without differences (P > 0.05) due to treatment or interaction treatment*time. Implications. These results suggest that the inclusion levels of TC and EOO in the diet were not enough to affect rumen fermentation or methane production. Therefore, it is necessary to evaluate higher levels of these compounds in sheep's diets. Conclusion. The addition of CT or the different levels of EOO included in sheep's diets evaluated in this study did not affect total gas production, CH4, CO2, pH, concentration of N-NH3, AGV, and pH.