Effect of cereal grain type and corn grain harvesting and processing methods on intake, digestion, and milk production by dairy cows through a meta-analysis

Abstract

A meta-analysis was performed to determine the influence of cereal grain type and corn grain harvesting and processing methods, dietary starch, rumen-digestible starch, and forage NDF concentrations on intake, digestion, and lactation performance by dairy cows using a data set comprising 414 treatment means from 102 peer-reviewed journal reports from 2000 to 2011. Categories for corn processing were dry ground, cracked or rolled corn (DRY), high-moisture shelled or ear corn (ENS), and steam-flaked or -rolled corn (STM); categories for kernel mean particle size were 500 to 1,000, 1,000 to 1,500, 1,500 to 2,000, 3,000 to 3,500, and 3,500 to 4,000 µm for dry corn and <2,000 and ≥2,000 µm for ensiled corn. Dietary starch and forage NDF concentrations were used as continuous variables. Data were analyzed using PROC MIXED in SAS (SAS Institute Inc., Cary, NC), with treatment as fixed and trial as random effects. Total-tract starch digestibility was reduced and milk fat content was greater for DRY compared with ENS or STM. Total-tract digestibility of dietary starch was reduced for both DRY and ENS as particle size increased. Increased dietary starch concentrations increased milk yield and protein content, but decreased ruminal and total-tract NDF digestibilities and milk fat content. Dry matter intake, total-tract starch digestibility, and milk protein concentration decreased as forage NDF in the diet increased. Total-tract starch digestibility was positively related to ruminal (percentage of starch intake) and postruminal (percentage of duodenal flow) starch digestibilities.

Effects of Grain Processing with Focus on Grinding and Steam- Flaking on Dairy Cow Performance

“…It has been shown that this protein matrix by blocking the absorption sites or by inluencing enzyme binding may reduce the surface availability of starch to host enzyme and ruminal bacteria [25]. In addition, the results of several studies have shown that hydrophobic properties of grain protein matrix, associated with type and location of proteins, could be responsible for the diferences in starch digestion between rapidly digested grains such as wheat, barley, and rice, and slowly digested grains such as maize and sorghum [2,24]. Processing is necessary for feed grains to break the protective seed coat [3,5] especially for the grains such as maize and sorghum [11], and the ibrous hull in case of barley and oats, to improve their digestibility in the digestive tract of animals [5].…”

“…Feed grains containing starch such as corn, wheat, barley, and sorghum, as a primary source of energy, are commonly fed to livestock to improve meat or milk productions [1]. Improving starch utilization may improve lactation performance in cows and reduce feed costs, especially when grain price is high [2]. Whole grain with an intact pericarp is largely or entirely resistant to digestion by ruminants because whole kernels are resistant to bacterial and host enzyme accessing to endosperm of grain kernel in the rumen and in the intestine, respectively [3,4].…”

Performance, carcass and ruminal fermentation characteristics of heifers fed concentrates differing in energy level and cereal type (corn vs. wheat)

“…However, most of scientific research to evaluate the dietary effects of corn and wheat has been carried out in dairy cows (reviewed by Ferraretto et al, 2013). Some comparative studies have also been conducted with beef cattle but, in most of them, the concentrates also included monensin, which is currently banned in Europe and can mask the effects of different cereals on ruminal fermentation (Yang et al, 2014).…”

Processamento de grãos de milho para vacas leiteiras em pastagem tropical

“…Alto milho diminuiu o teor de gordura do leite de 3,38 para 3,26% (P=0,04) e aumentou o teor de proteína de 2,99 para 3,03% (P=0,05) e a eficiência alimentar de 1,50 para 1,57kg de leite/kg de consumo (P=0,03). Em meta-analise realizada por Ferraretto et al (2013) avaliando 414 trabalhos, relatou redução no teor de gordura do leite de 3,59% para 3,41% nos animais alimentados com silagem de grão úmido em comparação com milho maduro moído, não foi relatada alteração no teor da proteína do leite.…”