Effect of type (barley vs. maize) and processing (grinding vs. dry rolling) of cereal on ruminal fermentation and microbiota of beef calves during the early fattening period

• Published in: Animal feed science and technology 2015-01, Vol.199, p.113-126
• Main Authors: Gimeno, A., Alami, A. Al, Abecia, L., de Vega, A., Fondevila, M., Castrillo, C.
• Format: Article
• Language: English
• Subjects: Acidosis; Beef cattle; Concentrate processing; Hordeum vulgare; Microbiota; Rumen; Rumen environment; Streptococcus bovis; Zea mays
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2014.11.008

•Acidosis is the most important nutritional disorder in intensively reared cattle.•Type of cereal in the concentrate and its processing can be key factors in acidosis.•In our experiment rumen fermentation and pH were not affected by cereal type.•Rumen fermentation was more buffered when dry-rolled cereals (vs. ground) were fed.•Cereal type and its processing had only a minor effect on rumen microbiota. Ruminal acidosis is the most important nutritional disorder in intensively reared cattle and can be aggravated depending on the type of cereal in the concentrate and its processing, which affect the feed intake pattern and rumen fermentation and microbiota. Two compound feeds were formulated with a 0.60 mixture of maize and barley in proportions of 75:25 (M) and 25:75 (B), ground to 3.5mm (G) or dry-rolled (R). Eight 3-month old, rumen cannulated Holstein male calves were fed the experimental concentrates together with barley straw ad libitum, four of them receiving concentrate M and the other four receiving concentrate B throughout the experiment. Concentrates were offered to each animal in the two presentation forms in two 35-day periods, following a crossover arrangement. On days 33 and 35 of each period, rumen contents were sampled just before the morning feed distribution (8:30h) and 4 and 8h later to measure pH and determine volatile fatty acid (VFA), ammonia and lactic acid concentrations, as well as to characterise rumen bacterial community by qPCR. The pattern of feed intake was also monitored over the sampling days. The main cereal included in the concentrate scarcely affected ruminal fermentation. The higher fermentation rate of barley-based concentrates could be partly counterbalanced by a higher straw intake. Animals fed R cereals showed higher rumen pH (6.09 vs. 5.77, P