Intramuscular fatty acid composition of steers finished on oat pastures mixture with vetch or cornmeal supplementation / Composição de ácidos graxos da gordura intramuscular de novilhos terminados em pastagem de aveia consorciada com ervilhaca ou suplementados com grão de milho moído

ABSTRACT: The effects of energetic supplementation and mixture vetch (Vica sativa L.) were studied to evaluate the intramuscular fatty acid profile of steers finished on oat (Avena sativa L.) pastures. Eighteen 21-month-old crossbred steers were evaluated. The experiment was carried out in three treatments and six repetitions: oat pasture (OA), oat pasture + vetch (OA + VET), and oat pasture + supplementation (OA + SUP). Supplementation comprised the addition of corn meal at a daily dose of 1% of the animals' body weight. Steers receiving supplementation had higher lipid content in Longissimus lumborum than did those fed with OA + VET (1.25 vs 1.02%), whereas those fed with OA (1.15%) showed intermediate values. Conjugated linoleic acid levels were higher in steers fed OA (0.57%) and OA + SUP (0.59%), whereas the highest amount of omega-3 fatty acids was observed in animals fed OA + VET (3.32%). Pasture-finishing without supplementation resulted in a lower ratio of n-6:n-3 (3.14). Steers finished in oat mixture with vetch showed healthier intramuscular fat than did those finished with cornmeal supplementation; importantly, the higher the amount of PUFAs, the better n-6:n-3 ratio.

RESUMO: Os efeitos da suplementação energética e da ervilhaca (Vica sativa L.) foram estudados para avaliar o perfil de ácidos graxos intramusculares de novilhos terminados em pastagens de aveia (Avena sativa L.). Foram avaliados 18 novilhos mestiços com 21 meses de idade. O experimento foi realizado em três tratamentos e seis repetições: pastagem de aveia (OA), pastagem de aveia + ervilhaca (OA + VET) e pastagem de aveia + suplementação (OA + SUP). A suplementação compreendeu a adição de fubá na dose diária de 1% do peso corporal dos animais. Os novilhos que receberam suplementação apresentaram maior teor lipídico no Longissimus lombar do que aqueles alimentados com OA + VET (1,25 contra 1,02%), enquanto aqueles alimentados com AO (1,15%) apresentaram valores intermediários. Os níveis de ácido linoléico conjugado foram maiores em novilhos alimentados com AO (0,57%) e OA + SUP (0,59%), enquanto a maior quantidade de ácidos graxos ômega-3 foi observada em animais alimentados com OA + VET (3,32%). Animais terminados em pastagens sem suplementação apresentaram menor proporção de n-6: n-3 (3,14). Novilhos terminados em pastagem de aveia com ervilhaca apresentaram gordura intramuscular mais saudável do que aqueles terminados com suplementação de milho moído, uma vez que apresentaram maior quantidade de PUFAs e melhor a relação n-6: n-3.

Performance and ingestive behavior of steers on integrated system using legume and/or energy supplementation.

This study aimed to evaluate the effect of a mixture of temperate and legume grasses with or without energy supplementation on the performance and feeding behavior of finishing beef steers. Eighteen Nellore-Zebu steers, average 23 months old and body weight (BW) of 380 kg, were used in a continuous grazing system, in a randomized block experimental design. Treatments were ORS: oat (Avena strigosa Schreb) + annual ryegrass (Lolium multiflorum Lam) + supplementation with corn bran; ORVS: oat + ryegrass + vetch (Vicia sativa L.) + supplementation with corn bran; and ORV: oat + ryegrass + vetch. Evaluations were conducted on pasture (forage mass, sward height, herbage accumulation, botanical composition, and chemical composition) and animal (performance and ingestive behavior). Stocking rate and forage mass were greater in treatments with energy supplementation (ORVS and ORS), thus presenting greater sward heights compared to the treatment without supplementation. There was greater participation of oats and ryegrass when vetch was absent (ORS). The presence of supplement (ORS and ORVS) increased the presence of oat stem. The presence of the supplement caused the contribution of the vetch to be lower, likely because of the higher animal load of these treatments. The higher presence of vetch increased crude protein content in the ORV treatment. The ORS exhibited greater gain per area compared to the ORV. Supplemented animals had lower grazing and greater idle time. The ORS treatment animals spent more time in other activities and consumed supplementation and less time grazing than the other treatments. The absence of supplement (ORV) caused the animals to spend more time grazing. Animals not supplemented showed a higher duration of daily chewing, number of chews per minute, number of daily chews, daily number of bites, and station numbers.

Backgrounding steers on temperate grasses mixed with vetch and/or using energy supplementation.

OBJECTIVE: The aim was to evaluate backgrounding beef steers on oat + ryegrass pastures mixed with vetch and/or using energy supplementation. METHODS: A randomized block design with three treatments and three replications was used. The treatments were: grass + supplement (oat + ryegrass + supplementation), legume + supplement (oat + ryegrass + vetch + supplementation) and grass + legume (oat + ryegrass + vetch). A continuous grazing system with a variable stocking rate was used. Twenty-seven intact crossbred steers (1/4 Marchigiana, 1/4 Aberdeen Angus and 2/4 Nellore) aged 7 months old and average weight of 190 kg were used. Steers were supplemented at 1% of the body weight of ground corn. The experiment lasted 84 days, between May and August 2014. Behavioral assessments were performed two times per experimental period, for 24 hours. RESULTS: The forage mass was different between treatments, being greater for steers fed without legume. The accumulation rate, forage allowance, and stocking rate did not differ between treatments due to the adequate adjustment of forage allowance. The final weight of animals, as well as the dry matter intake (kg/d), did not differ between treatments. However, forage intake was higher for non-supplemented animals in relation to supplemented steers. Supplement intake did not alter the total digestible nutrient intake due to pasture quality. Animals fed grass + supplement had higher live weight gain per area than those fed grass + legume. Animals without supplementation spent more time in grazing. CONCLUSION: Feeding behavior was not altered by mixing with vetch or supplementation. Non-supplemented animals started the grazing peak earlier and spent more time in grazing than those supplemented; however, the average daily gain was similar between treatments. The live weight gain per hectare was 47% higher in pastures in which the animals received supplementation compared with those mixed with vetch, a consequence of the substitutive effect.

Evaluation of sonication treatment and buffer composition on rumen bacteria protein extraction and carboxymethylcellulase activity.

BACKGROUND: The methodological procedures for studying the fibrolytic activity of rumen bacteria are not clearly established. In this study the efficiency of sonication treatment and buffer composition (i.e. buffer varying in tonicity or pH) on the level of protein extraction from the residue of forage samples incubated in the rumen of a grazing steer and the effect of buffer composition or CaCl2 concentration on the carboxymethylcellulase (CMCase) activity of the released protein were evaluated. RESULTS: The amount of protein released from the residue of incubation was higher (P < 0.05) for the sonicated material and increased linearly with increasing buffer pH (P < 0.05). The CMCase activity of the released protein was not improved by sonication treatment, whereas it was higher (P < 0.05) for hypotonic than for hypertonic buffer. Both linear and quadratic effects (P < 0.05) of buffer pH on CMCase activity were significant, with CMCase activity being maximal at pH 5.4-6.1. CMCase activity was higher (P < 0.05) at a CaCl2 concentration of 1 mmol L(-1) compared with lower values. CONCLUSION: Although sonication treatment increases the amount of protein extracted from rumen bacteria adhered to the residue of incubation, the CMCase activity of the released protein might be measured without sonication treatment and should be carried out with a hypotonic buffer solution that includes a calcium source. When pH is not a treatment factor, the buffer pH should be between 5.5 and 6.

Suplementacão com diferentes níveis de silagem de milho para vacas de descarte de diferentes grupos genéticos submetidas ao pastejo / Different levels of corn silage as supplementation for cull cows from different genetic groups submitted to grazing

O trabalho foi realizado objetivando-se avaliar o efeito da suplementacão com silagem de milho sobre o desempenho de vacas de descarte em terminacão, em pastagem de aveia preta (Avena strigosa) e azevém (Lolium multiflorum). A silagem de milho utilizada foi do híbrido AG-5011, contendo 6,59 por cento de Proteína Bruta. Foram utilizadas 30 vacas de descarte dos grupos genéticos Charolês (C) » Nelore (N) ou N » C com média de idade de 5 anos, recebendo ou não oferta de 1,25 por cento do peso vivo (PV) de silagem de milho (matéria seca) ou oferta à vontade da mesma silagem. Não houve interacão entre grupo genético e oferta de suplemento. Animais que receberam silagem à vontade apresentaram maior consumo absoluto de suplemento (4,57 contra 4,34kg), desaparecendo esta diferenca quando o consumo foi expresso em percentagem do peso vivo (1,07 contra 0,99 por cento). As vacas que receberam suplemento apresentaram maior ganho de peso médio diário (GMD) em comparacão às que não receberam (0,879kg), independente do nível de oferta. A oferta de silagem à vontade não proporcionou maior GMD (1,175kg) em relacão aos que receberam 1,25 por cento do PV (1,214kg). O maior consumo de silagem proporcionou maior escore corporal final (3,42 pontos), sendo que as vacas que receberam 1,25 por cento do PV (3,26 pontos), não diferiram daquelas que não receberam suplemento (3,19 pontos). As vacas C » N apresentaram maior consumo absoluto de suplemento (3,05 contra 2,89kg), maior GMD (1,196 contra 0,983kg/animal/dia) e maior escore corporal ao final do experimento (3,37 contra 3,21 pontos).