The aim of this study was to evaluate the effect of dietary incorporation of tannin-rich woody species on meat oxidative stability, carcass traits and meat quality in goats. Two tannin-rich species were tested using a three-treatments feeding trial, where treatments consisted of: Larrea divaricata and Acacia aroma both at 12.5% in dry matter basis of the diet and a control diet (alfalfa hay). All feeding diets were iso-protein and iso-energy. Carcass conformation, carcass compactness, carcass fatness and subcutaneous fat deposition were evaluated. Intake, liveweigh, Longissimus thoracis et lumborum muscles of goats were analyzed in order to evaluate quality parameters such as pH value, instrumental color evaluation, water holding capacity, total phenolic content, antioxidant activity, meat oxidative stability and fatty acid profiles in meat. Feed intake, liveweight gain, carcass and meat traits did not differ among treatments. Changes in meat lipid profile among treatments were observed for oleic and elaidic acid contents. Meat total phenolic content and antioxidant activity did not differ among treatments; although, meat oxidative status after storage at room temperature, as well as under refrigerated and frozen conditions were different between control and both supplemented groups. The inclusion of Acacia aroma and Larrea divaricata leaves in goat diet enhanced meat oxidative stability. Modulation of the ruminal biohydrogenation of fatty acids produced by condensed tannins of these plant species need to be further investigated.

This study evaluated enteric methane (CH₄) emissions, dry matter intake (DMI), and performance in rearing beef heifers fed either a Guinea-grass-only diet (0WCS) or Guinea grass supplemented with whole cottonseed (WCS) at 0.5% of body weight (BW). Twenty-four Braford heifers were randomly allocated into four pens (three animals per pen) per treatment over two experimental periods. Methane emissions were measured using the SF₆ tracer technique. Heifers receiving WCS supplementation produced 29% less CH₄ (120.64 vs. 169.54 g/day for 0.5WCS and 0WCS, respectively; p = 0.02) and showed a 22% reduction in CH₄ yield (7.30% vs. 9.41% of gross energy intake; p = 0.02). Methane intensity was 33% lower in supplemented heifers (0.37 vs. 0.55 g CH₄/kg BW; p = 0.01). However, WCS supplementation significantly reduced total DMI and forage DMI (p = 0.01 and p < 0.01, respectively). In terms of performance, heifers in the 0.5WCS group gained 0.28 kg/day, while those in the 0WCS group lost 0.10 kg/day. These results indicate that WCS supplementation mitigates CH₄ emissions while improving weight gain in beef heifers fed low-quality forage diets, making it a promising strategy for enhancing the sustainability of beef cattle production systems.

Introducción. El crecimiento y la maduración folicular implican una serie de transformaciones de diversos componentes del folículo, como el ovocito, las células de la granulosa y de la teca. Varios factores de crecimiento, incluyendo factor de crecimiento de diferenciación 9 (GDF9), proteína morfogénica ósea 15 (BMP15) y factor de crecimiento de fibroblastos básico (FGF2) son importantes para el desarrollo folicular y maduración de ovocitos, por su capacidad de aumentar la proliferación de las células de la granulosa, teca y el estroma ovárico. Objetivo. Evaluar la expresión de los factores de crecimiento GDF9, BMP15, FGF2 y sus principales receptores: el receptor 1 del factor de crecimiento transformante beta (TGFβ-R1), el receptor de la proteína morfogénica del hueso tipo IB (BMPR-IB) y el receptor del factor de crecimiento fibroblástico 2 (FGFR2) en células foliculares bovinas. Materiales y métodos. Se realizó la extracción de ARN total de pooles de ovocitos (OOs) y células del cumulus (CCs) de complejos cumulus-ovocito (COCs) y del pellet de células foliculares (PCs) provenientes de 70 ovarios obtenidos de 96 vaquillonas para carne, colectados en un frigorífico local. Los patrones de expresión de los factores de crecimiento y sus receptores en las células foliculares bovinas fueron evaluados por retro-transcripción seguida de la reacción en cadena de la polimerasa (RT-PCR). Resultados. La presencia de los transcriptos de ARNm de los genes GDF9, BMP15, FGF2, TGFβ-R1, BMPR-IB y FGFR2 fue detectada por RT-PCR en todas las células estudiadas. Es la primera vez que se reporta en ovocitos bovinos la expresión de los receptores TGFβ-R1 y BMPR-IB. Conclusiones. La presencia de transcriptos de factores de crecimiento y sus receptores en las células estudiadas, indica que estos factores podrían actuar como reguladores paracrinos y autocrinos de la foliculogénesis.

This study was designed to evaluate the effect of corn dried distiller´s grains (DDGS) supplementation on feed intake, total tract digestibility, and ruminal fermentation of beef steers fed low-quality Guinea grass (Megathyrsus maximus, cv. Gatton panic). Twelve Braford crossbred steers were housed in individual pens (n = 4 steers/treatment), provided with three levels of DDGS supplement: 0%, 0.6%, or 1.2% BW. Steers were blocked by live weight and randomly assigned to treatments within the block. Corn DDGS supplementation increased total OM intake (21.55, 40.23, and 56.69 g/kg BW0.75) and tract OM digestibility (46.33, 49.03, and 72.39 % DM). Total tract digestible OM, CP, NDF and EE intake also increase in response to DDGS supplementation. Forage OM intake decreased when supplementation level reached 1.2 % BW. Also, ruminal pH decreased with DDGS supplementation level (6.88, 6.47, and 6.27). No differences were observed in total volatile fatty acids (VFA) concentration; however, the molar proportion of acetate decreased (77.98, 73.90, and 67.29 % Total VFA) as well as acetate: propionate ratio (4.38, 3.48, and 2.74). On the contrary, propionate proportions increased (18.32, 21.86, and 24.81 % Total VFA). Levels of ammonia and lactate were within suggested values for optimal fermentation and bacterial growth. Low-quality grass supplementation with corn DDGS increased total OM intake and digestibility. Also, DDGS inclusion favorably altered volatile fatty acids profile by reducing the acetate to propionate ratio regarding forage-only diets.

Se evaluaron parámetros de desempeño productivo y de calidad de la res y la carne de 18 novillos de raza Criollo Argentino (CrA), Braford (Bra) y la cruza F1 de CrA x Bra (F1). Los animales fueron sometidos a un engorde a corral durante 70 días y fueron sacrificados a una edad promedio de 19,3 meses. Los novillos Bra y F1 lograron mayor engrasamiento subcutáneo que CrA (8.05 vs 5.30 mm, P = 0.0008), aunque no se hallaron diferencias ­1 en el peso vivo definitivo (418 kg, P = 0.819), ni en la ganancia diaria de peso vivo (1.39 kg d , P = 0.8196) ni sobre el nivel de grasa intramuscular (1.78 %, P = 0.1085) entre genotipos. Las reses de CrA presentaron una tendencia a mayor índice de muscularidad (15.27 vs 14.21, P = 0.0521) y mayor proporción de cortes de carne vendible o cortes minoristas respecto a las de Bra y F1 (51.97 vs 50.56 %, P = 0.0001). Asimismo, las reses de CrA presentaron tendencia a mayor % de magro que las de Bra y F1 (61.19 vs 55.22 %, P = 0.0558), menor % de grasa subcutánea que Bra (7.39 vs 11.05 %, P = 0.0066) y menor % de grasa intermuscular que F1 (9.33 vs 13.90 %, P = 0.0361). La carne de Bra presentó mayores valores de luminosidad (L*) respecto a la de CrA y F1 (40.09 vs 36.19, P = 0.0095) y CrA presentó mayor índice de rojo (a*) respecto de ambos genotipos (18.32 vs 15.31, P = 0.0005), lo que resultó en diferencias de color entre CrA y Bra perceptibles por el ojo humano. Los demás parámetros de calidad de carne evaluados (pH, capacidad de retención de agua, pérdidas por cocción y dureza) no difirieron entre los genotipos estudiados.

This study evaluated enteric methane (CH₄) emissions, dry matter intake (DMI), and performance in rearing beef heifers fed either a guinea grass-only diet (0WCS) or guinea grass supplemented with whole cottonseed (WCS) at 0.5% of body weight (BW). Twenty-four Braford heifers were randomly allocated into four pens (three animals per pen) per treatment over two experimental periods. Methane emissions were measured using the SF₆ tracer technique. Heifers receiving WCS supplementation produced 29% less CH₄ (120.64 vs. 169.54 g/day for 0.5WCS and 0WCS, respectively; p = 0.02) and showed a 22% reduction in CH₄ yield (7.30% vs. 9.41% of gross energy intake; p = 0.02). Methane intensity was 33% lower in supplemented heifers (0.37 vs. 0.55 g CH₄/kg BW; p = 0.01). However, WCS supplementation significantly reduced total DMI and forage DMI (p = 0.01 and p < 0.01, respectively). In terms of performance, heifers in the 0.5WCS group gained 0.24 kg/day, while those in the 0WCS group lost 0.10 kg/day. These results indicate that WCS supplementation mitigates CH₄ emissions while improving weight gain in beef heifers fed low-quality forage diets, making it a promising strategy for enhancing the sustainability of beef cattle production systems.