RESUMO

Monensin and virginiamycin are included in beef cattle finishing diets as prophylaxis to minimize the incidence of ruminal acidosis and liver abscesses. Due to different and probably complementary modes of action, this study aimed to determine the effects of a combination of monensin and virginiamycin, both included in the diet at recommended doses, on ruminal health, the occurrence of liver abscesses, and growth performance of feedlot-finished cattle. One hundred and forty-four steers (6 animals/pen) were fed 1 of 3 corn-based finishing diets containing 30 mg of monensin (MN), 25 mg of virginiamycin (VM), or 30 and 25 mg of monensin and virginiamycin (MN + VM), respectively, per kilogram of dry matter. Ruminal pH probes were inserted into two animals per pen and set to record pH every 10 min. On d 100, animals were slaughtered, and rumens and livers were recovered, on which occurrence and degree of ruminal damage, prevalence and number of liver abscesses, and liver scores (A-: livers with no more than two small abscesses; A+: livers with at least one large abscess or more than four medium abscesses; A: any other abscessed liver) were determined. Simultaneous inclusion of monensin and virginiamycin resulted in a 4.3% decrease (P < 0.04) in dry matter intake (DMI; 8.8, 9.2, and 9.2 ± 0.19 kg/d for MN + VM, MN, and VM-fed animals, respectively) and similar (P > 0.13) average daily body weight gain (ADG; 1.49 ± 0.021 kg/d) and hot carcass weight (HCW; 269 ± 1.7 kg), compared with feeding diets containing one additive or the other. Therefore, in terms of ADG, a 9.4% improvement (P < 0.01) in feed efficiency was observed in MN + VM-fed animals. Backfat thickness (5.6 ± 0.08 mm) and ribeye area (69.9 ± 0.53 cm2) remained unaffected (P ≥ 0.74), as well as the minimum (4.98 ± 0.047), mean (6.11 ± 0.037), and maximum ruminal pH (7.23 ± 0.033) values and the time (125 ± 22.3 min/d), area (57.67 ± 12.383 pH × h), and episodes (22 ± 3.8 bouts) of pH below 5.6 (P ≥ 0.12). Overall, prevalence (24 ± 3.4%) and the number of liver abscesses (1.6 ± 0.14 abscesses/abscessed liver), liver scores (20 ± 3.1% of A- and 4 ± 1.8% of A livers), and prevalence (67 ± 3.5%) and degree of damage to the ruminal epithelium (2.5 ± 0.22% affected surface) were similar (P ≥ 0.18) across treatments; however, the occurrence of ruminal lesions tended (P ≤ 0.07) to be associated with that of liver abscesses and reduced ADG when feeding monensin alone.

RESUMO

Objetivou-se avaliar os efeitos da inclusão de virginiamicina (VM) em dois níveis, ao suplemento proteico-energético para bovinos de corte em crescimento com dieta a base de gramínea tropical no período seco do ano. Foram constituídos três tratamentos: tratamento controle, apenas Suplemento Mineral COMIGO - Produção - F.10 proteico-energético (SPE); tratamento virginiamicina 100 (VM 100), SPE + 108 mg de (Phigrow®) VM/animal/dia e tratamento virginiamicina 200 (VM 200), SPE + 216 mg de (Phigrow®) VM/animal/dia. As variáveis analisadas foram o consumo de suplemento (CSPE), ganho médio diário (GMD), medidas biométricas e escore de condição corporal (ECC) no experimento 1 e o consumo médio diário de suplemento (CSM), pH ruminal, nitrogênio amoniacal, degradabilidade ruminal in situ da matéria seca (MS), da fibra em detergente acido (FDN) e da fibra em detergente neutro (FDA) no experimento 2. Não houve diferença estatística para GMD, CSPE e para medidas biométricas (P>0,05), GMD para VM 200 de 0,431; VM 100 de 0,391 e controle de 0,398 kg/animal/dia. Não houve diferença significativa (P>0,05) do pH ruminal, da concentração de nitrogênio amoniacal e das variáveis analisadas na degradabilidade ruminal in situ da MS, da FDN e da FDA. A virginiamicina veiculada no SPE para bovinos de corte sob pastejo pode promover a variação de consumo, não promoveu efeitos significativos nos valores do pH ruminal e do nitrogênio amoniacal e não demonstram efeitos significativos sobre a degradabilidade da MS, FDN e FDA.

This study aimed to evaluate the effects of including virginiamycin (VM) in two levels, the proteinenergy supplement for growing beef cattle diet with the tropical grass base in the dry season. Three treatments were evaluated: control treatment, only Mineral Supplement ME - Production - F.10 proteinenergy (SPE); 100 virginiamycin treatment (VM 100) + SPE 108 mg (Phigrow®) VM / animal / day and treatment virginiamycin 200 (200 MV) + SPE 216 mg (Phigrow®) VM / animal / day. The variables analyzed were the supplement intake (SI), average daily gain (ADG), biometric measurements and body condition score (BCS) in experiment 1 and the average daily supplement intake (ADSI), ruminal pH, ammonia nitrogen, in situ ruminal degradability of dry matter (DM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) in experiment 2. There was no statistical difference for ADG, SI and biometric measurements (P>0.05), ADG for VM 200 of 0,431; VM 100 of 0.391 and control 0.398 kg/animal/day. There was no significant difference (P>0.05) for ruminal pH, the ammonia concentration and the variables at the in situ degradability of DM, NDF and ADF. The virginiamycin conveyed in SPE for beef cattle grazing can promote changes in consumption did not cause significant effects on the values of ruminal pH and ammonia nitrogen and do not show significant effects on the degradability of DM, NDF an and ADF. The virginiamycin conveyed in SPE for beef cattle grazing can promote changes in consumption did not cause significant effects on the values of ruminal pH and ammonia nitrogen and do not show significant effects on the degradability of DM, NDF and ADF.

Assuntos

RESUMO

Objetivou-se avaliar os efeitos da inclusão de virginiamicina (VM) em dois níveis, ao suplemento proteico-energético para bovinos de corte em crescimento com dieta a base de gramínea tropical no período seco do ano. Foram constituídos três tratamentos: tratamento controle, apenas Suplemento Mineral COMIGO - Produção - F.10 proteico-energético (SPE); tratamento virginiamicina 100 (VM 100), SPE + 108 mg de (Phigrow®) VM/animal/dia e tratamento virginiamicina 200 (VM 200), SPE + 216 mg de (Phigrow®) VM/animal/dia. As variáveis analisadas foram o consumo de suplemento (CSPE), ganho médio diário (GMD), medidas biométricas e escore de condição corporal (ECC) no experimento 1 e o consumo médio diário de suplemento (CSM), pH ruminal, nitrogênio amoniacal, degradabilidade ruminal in situ da matéria seca (MS), da fibra em detergente acido (FDN) e da fibra em detergente neutro (FDA) no experimento 2. Não houve diferença estatística para GMD, CSPE e para medidas biométricas (P>0,05), GMD para VM 200 de 0,431; VM 100 de 0,391 e controle de 0,398 kg/animal/dia. Não houve diferença significativa (P>0,05) do pH ruminal, da concentração de nitrogênio amoniacal e das variáveis analisadas na degradabilidade ruminal in situ da MS, da FDN e da FDA. A virginiamicina veiculada no SPE para bovinos de corte sob pastejo pode promover a variação de consumo, não promoveu efeitos significativos nos valores do pH ruminal e do nitrogênio amoniacal e não demonstram efeitos significativos sobre a degradabilidade da MS, FDN e FDA.(AU)

This study aimed to evaluate the effects of including virginiamycin (VM) in two levels, the proteinenergy supplement for growing beef cattle diet with the tropical grass base in the dry season. Three treatments were evaluated: control treatment, only Mineral Supplement ME - Production - F.10 proteinenergy (SPE); 100 virginiamycin treatment (VM 100) + SPE 108 mg (Phigrow®) VM / animal / day and treatment virginiamycin 200 (200 MV) + SPE 216 mg (Phigrow®) VM / animal / day. The variables analyzed were the supplement intake (SI), average daily gain (ADG), biometric measurements and body condition score (BCS) in experiment 1 and the average daily supplement intake (ADSI), ruminal pH, ammonia nitrogen, in situ ruminal degradability of dry matter (DM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) in experiment 2. There was no statistical difference for ADG, SI and biometric measurements (P>0.05), ADG for VM 200 of 0,431; VM 100 of 0.391 and control 0.398 kg/animal/day. There was no significant difference (P>0.05) for ruminal pH, the ammonia concentration and the variables at the in situ degradability of DM, NDF and ADF. The virginiamycin conveyed in SPE for beef cattle grazing can promote changes in consumption did not cause significant effects on the values of ruminal pH and ammonia nitrogen and do not show significant effects on the degradability of DM, NDF an and ADF. The virginiamycin conveyed in SPE for beef cattle grazing can promote changes in consumption did not cause significant effects on the values of ruminal pH and ammonia nitrogen and do not show significant effects on the degradability of DM, NDF and ADF.(AU)

Assuntos