ABSTRACT
The early attainment of puberty in heifers is essential for the profitability of the cow-calf farm. This study aimed to evaluate the impact of juvenile average daily gain (ADG) and sire's expected progeny difference (EPD) on puberty of crossbred beef heifers. Sixty Angus × Nellore heifers early weaned (age = 102 ± 4.3 d; initial BW = 103 ± 4.7 kg) were used in a 2 × 2 factorial arrangement. The factor 1 was the sire's EPD for scrotal circumference, in which heifers born from sires with positive EPD were considered precocious (P), and heifers born from sires with negative EPD were considered non-precocious (NP). The factor 2 was the high (HG; ADG = 0.9 kg; ad libitum) and medium ADG (MG; ADG = 0.7 kg) from 3rd to 7th month of age (1st phase). After 1st phase until puberty, all heifers were fed ad libitum (2nd phase). Statistical analysis was performed by SAS. There was an interaction between factors for DMI in the 1st phase (P = 0.02), which PHG heifers had higher DMI than NPHG. There was no effect on puberty rate, BW, age and BCS at puberty comparing HG vs. MG. However, favorable sires' EPD for scrotal circumference induced a higher proportion of puberty (P 87% vs. NP 59%) at 15 months of age. Thus, the ADG in juvenile age did not affect puberty rate, but sires with positive EPD increased puberty rate of Angus × Nellore heifers in heifers fed a high gain diet.
Subject(s)
Animal Feed , Sexual Maturation , Cattle , Animals , Female , Animal Feed/analysis , Diet/veterinary , WeaningABSTRACT
Two experiments were designed to evaluate the impacts of supplementing lasalocid (LAS), narasin (NAR), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, and blood parameters (Exp. 1), as well as feed intake and performance (Exp. 2) of Nellore cattle consuming a forage-based diet. In Exp. 1, 32 rumen-fistulated Nellore steers (initial shrunk body weight [BW] = 355 ± 4.4 kg) were assigned to a randomized complete block design. Within block, animals were randomly assigned to one of four treatments: 1) forage-based diet without feed additives (CON), 2) CON diet plus 13 mg/kg of dry matter (DM) of NAR, 3) CON diet plus 20 mg/kg of DM of sodium LAS, or 4) CON diet plus 20 mg/kg of DM of VRM. No treatment effects were detected (P ≥ 0.32) for intake and apparent digestibility of nutrients. Steers fed NAR had the lowest (P ≤ 0.01) molar proportion of acetate on day 28, 56, and 112 vs. CON, LAS, and VRM steers, whereas acetate did not differ (P ≥ 0.25) between LAS, VRM, and CON steers from day 28 to 84. On day 112, steers fed LAS had a lower (P < 0.02) molar proportion of acetate vs. VRM and CON, whereas it did not differ between CON and VRM (P > 0.33). Steers receiving NAR had a greater (P ≤ 0.04) ruminal propionate vs. CON, LAS, and VRM, whereas LAS steers had greater (P < 0.04) propionate vs. CON and VRM steers on day 28 and 112, and it did not differ (P > 0.22) between CON and VRM. In Exp. 2, 160 Nellore bulls were blocked by initial shrunk BW (212 ± 3.1 kg) in a 140-d feedlot trial. Diets contained the same treatments used in Exp. 1. Bulls fed NAR had greater (P < 0.02) average daily gain (ADG) vs. CON and VRM, and similar (P = 0.17) ADG between NAR and LAS, whereas ADG did not differ (P > 0.28) between LAS, VRM, and CON bulls. A treatment effect was detected (P = 0.03) for dry matter intake, being greater in NAR vs. CON, LAS, and VRM bulls, and similar (P > 0.48) between CON, LAS, and VRM bulls. A tendency was detected (P = 0.09) for feed efficiency, which was greater (P < 0.02) in NAR bulls vs. CON and VRM, and similar (P = 0.36) between NAR and LAS bulls. From day 112 to 140, bulls receiving NAR were heavier (P < 0.03) vs. CON, LAS, and VRM bulls, but no differences were observed (P > 0.51) between CON, LAS, and VRM bulls. Collectively, ruminal fermentation profile and intake were impacted by NAR supplementation, which partially contributed to the enhanced performance of Nellore bulls receiving a forage-based diet.
Feed additives are nutritional tools that benefit dietary digestibility and nutrient utilization, alter ruminal fermentation routes, and improve cattle growth and efficiency, thus increasing productivity and profitability in beef cattle systems. Nonetheless, most of the current research focuses on supplementing feed additives in high-concentrate diets. Leaving a significant gap in understanding the influence of feed additives in cattle consuming forage-based diets, especially molecules capable of altering the fermentation process and, consequently, beef cattle performance. Therefore, this experiment aimed to evaluate the impacts of supplementing narasin (NAR), lasalocid (LAS), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, feed intake, and performance of Bos indicus Nellore cattle consuming a forage-based diet. Including commercially available feed additives into forage-based diets did not impact nutrient intake and digestibility of nutrients. The inclusion of NAR affected ruminal fermentation parameters toward propionate production, positively contributing to animal performance. Ruminal fermentation characteristics and animal growth were not impacted by dietary LAS and VRM, which could be attributed to the dose used in the current experiment, despite the manufacturer's recommendation. This research provides insights into NAR as an important feed additive for forage-based beef cattle diets.
Subject(s)
Dietary Supplements , Lasalocid , Cattle , Animals , Male , Lasalocid/pharmacology , Propionates/metabolism , Rumen/metabolism , Animal Feed/analysis , Digestion , Diet/veterinary , Body Weight , FermentationABSTRACT
Essential oil (EO) from Brazilian red pepper leaves contains antimicrobial compounds that control Gram-positive bacteria in the rumen content, improving the efficiency of ruminal fermentation. The objectives of the present study were to evaluate the effects of the Brazilian red pepper leaves EO (Schinus terebinthifolius) as a substitute for monensin on performance, occurrence of coccidiosis by Eimeria ssp., carcass characteristics and meat composition of feedlot lambs. Forty-four lambs, 16 males (12 ½ Dorper × ½ Santa Inês and 4 Santa Inês) and 28 females (16 ½ Dorper × ½ Santa Inês and 12 Santa Inês), with 21.4 ± 1.05 kg of initial body weight (BW), were used in a randomized complete block design. The experiment lasted 56 days, divided into 2 periods of 28 days each. The treatments were defined by the inclusion of 8 ppm of monensin (MON), and the doses 0.14% (14EO), 0.28% (28EO) and 0.42% (42EO) of red pepper leaves essential oil (EO). At the end of 56 days, 32 lambs were slaughtered for the measurement of carcass parameters and meat composition. There was no interaction among treatments and periods for average daily gain (ADG), dry matter intake (DMI), feed efficiency (FE) and oocyst of Eimeria ssp. in feces. The treatments did not affect the ADG, DMI and FE; however, the monensin inclusion decreased the oocyst of Eimeria ssp. (P = 0.01). There was a tendency (P = 0.06) of increase in hot carcass yield for lambs fed 28EO compared to 14EO. In addition, the cold carcass yield was higher (P = 0.02) in the animals fed 28EO and 42EO. The subcutaneous fat thickness was not affected by the experimental diets; however, there was a tendency for lambs from 28EO and 42EO treatments to present higher body wall thickness (P = 0.07) and Longissimus muscle area (P = 0.07) when compared to MON. The higher doses of red pepper leaves EO increased the percentage of crude protein (P < 0.01) and mineral matter (P = 0.02) in the chemical composition of meat. Although the performance of lambs did not change, the inclusion of 0.28 and 0.42% red pepper leaves EO improve the carcass characteristics and change the meat composition, demonstrating the potential of the use of this additive in confined lamb diets. However, the monensin has greater potential to control coccidiosis in feedlot lambs compared with red pepper leaves EO.(AU)
O óleo essencial das folhas da aroeira possui compostos antimicrobianos que controlam a população de bactérias gram-positivas presentes no conteúdo ruminal, melhorando a eficiência do processo de fermentação. Os objetivos do presente estudo foram avaliar os efeitos do óleo essencial das folhas da aroeira (Schinus terebinthifolius) em substituição a monensina sobre o desempenho, ocorrência de coccidiose por Eimeria ssp., características de carcaça e da carne de cordeiros confinados. Quarenta e quatro cordeiros, 16 machos (12 ½ Dorper × ½ Santa Inês e 4 Santa Inês) e 28 fêmeas (16 ½ Dorper × ½ Santa Inês e 12 Santa Inês), com 21,4 ± 1,05 kg de peso inicial, foram utilizados em delineamento de blocos completos ao acaso. O experimento teve duração de 56 dias, divididos em 2 períodos de 28 dias cada. Os tratamentos foram definidos pela inclusão de 8 ppm de monensina sódica (MON) e as doses 0,14% (14OE), 0,28% (28OE) e 0,42% (42OE) do óleo essencial (OE) das folhas da aroeira. Ao final dos 56 dias, 32 animais foram abatidos para a mensuração dos parâmetros de carcaça e análise química da carne. Não houve interação entre tratamento e período experimental para ganho médio diário (GMD), consumo de matéria seca (CMS), eficiência alimentar (EA) e ocorrência de coccidiose. Não houve efeito das dietas experimentais sobre GMD, CMS e EA, entretanto, a inclusão de monensina reduziu o número de oocistos de Eimeria ssp. (P = 0,01). Houve tendência de aumento no rendimento de carcaça quente (P = 0,06) para os cordeiros alimentados com 28OE comparados com o tratamento 14OE. Além disso, o rendimento de carcaça fria foi maior (P = 0,02) para os animais alimentados com 28OE e 42OE. A espessura de gordura subcutânea não foi afetada pelas dietas experimentais, entretanto, houve tendência dos cordeiros dos tratamentos 28OE e 42OE apresentarem maior espessura de parede corporal (P = 0,07) e área de olho de lombo (P = 0,07) quando comparados a MON. As maiores doses de OE das folhas de aroeira aumentaram a porcentagem de proteína bruta (P < 0,01) e matéria mineral (P = 0,02) na composição química da carne dos cordeiros. Apesar de não alterar o desempenho dos cordeiros, a inclusão de 0,28 e 0,42% de OE das folhas de aroeira foi capaz de alterar as características de carcaça e composição química da carne, demonstrando o potencial de utilização desse aditivo em dietas para cordeiros confinados. Entretanto, a monensina possui maior capacidade de controlar a coccidiose em cordeiros confinados quando comparado ao OE das folhas da aroeira.(AU)
Subject(s)
Animals , Sheep , Anacardiaceae , Ionophores , Animal Feed/analysis , Plant ExtractsABSTRACT
Essential oil (EO) from Brazilian red pepper fruit contains compounds with antimicrobial activity, and could be possible substitutes for the antibiotics commonly used in ruminant nutrition. The objectives of the present study were to evaluate the effects of the Brazilian red pepper fruit EO (Schinus terebinthifolius) as a substitute for monensin on performance, carcass characteristics and meat of lambs fed high concentrate diets. Forty-eight lambs were used, 24 males (20 ½ Dorper × ½ Santa Inês and 4 Santa Inês) and 24 females (24 ½ Dorper × ½ Santa Inês), with 21.54 ± 0.88 kg of initial body weight (BW) and 78 ± 2.4 days of age, in a randomized complete block design. The experiment lasted 56 days, divided into 2 periods of 28 days each. The treatments were defined by the inclusion in diets of 8 ppm of monensin (MON), and the doses 0.14% (14EO), 0.28% (28EO) and 0.42% (42EO) of red pepper fruit EO. The additives were included in a base diet with a 10:90 of forage to concentrate ratio. At the end of 56 days, 32 animals were slaughtered for the measurement of carcass parameters and meat composition. There was no interaction among treatments and periods for average daily gain (P = 0.08), DM intake (P = 0.36), feed efficiency (P = 0.24) and oocyst of Eimeria ssp. in feces (P = 0.46). The treatments did not affect (P > 0.05) the average daily gain (ADG), dry matter intake (DMI) and feed efficiency. Lambs fed diets containing monensin had less (P < 0.01) oocyst/g compared with the diet 14EO. There was no effect of diets on carcass characteristics. The treatments with higher doses of the Brazilian red pepper fruit EO had reduced mineral content of meat compared to monensin. The red pepper fruit EO demonstrated the potential to replace monensin in feedlot lambs fed high concentrate diets, maintaining performance and carcass characteristics. However, the monensin has greater capacity to control coccidiosis in feedlot lambs.
Os óleos essenciais (OE) dos frutos de aroeira possuem compostos com atividade antimicrobiana, sendo possíveis substitutos aos antibióticos comumente utilizados na nutrição de ruminantes. Os objetivos do presente estudo foram avaliar os efeitos da inclusão do óleo essencial de aroeira fruta (Schinus terebinthifolius) como substituto da monensina sobre o desempenho, características de carcaça e da carne de cordeiros alimentados com dietas contendo elevado teor de concentrado. Foram utilizados 48 cordeiros, 24 machos (20 ½ Dorper × ½ Santa Inês e 4 Santa Inês) e 24 fêmeas (24 ½ Dorper × ½ Santa Inês), com peso inicial de 21,54 ± 0,88 kg e 78 ± 2,4 dias de idade, em delineamento de blocos completos casualizados. O experimento teve duração de 56 dias, divididos em 2 períodos de 28 dias cada. Os tratamentos foram definidos pela inclusão na dieta de 8 ppm de monensina sódica (MON) e as doses de 0,14% (14EO), 0,28% (28EO) e 0,42% (42EO) de óleo essencial dos frutos da aroeira. As dietas experimentais foram compostas por 10% de volumoso e 90% de concentrado. Ao final dos 56 dias, 32 animais foram abatidos para a mensuração dos parâmetros de carcaça e análise química da carne. Não houve interação entre tratamento e período para o ganho médio diário (P = 0,08), consumo de MS (P = 0,36), eficiência alimentar (P = 0,24) e contagem de oocistos de Eimeria ssp. (P = 0,46). Não houve efeito (P > 0,05) dos tratamentos no ganho de peso médio diário (GMD), consumo de matéria seca (CMS) e eficiência alimentar (EA). Cordeiros alimentados com dietas contendo monensina tiveram menor (P < 0,01) contagem de oocistos/g de fezes comparado com a dieta 14OE. Não houve efeito das dietas sobre as características de carcaça. A inclusão de 0,28 e 0,42% de OE de aroeira fruto reduziram a concentração de matéria mineral da carne dos cordeiros comparados ao tratamento MON. O OE dos frutos da aroeira demonstrou capacidade de substituir a monensina, apresentando resultados similares com relação ao desempenho e características de carcaça. Entretanto, a monensina apresentou maior capacidade no controle de coccidiose
