Abstract
The objective of this study was to evaluate intake, in vitro and apparent digestibility and ruminal parameters of Holstein cows that were confined and fed corn silage and concentrate containing: ground sunflower seeds (GS); ground sunflower seeds treated with 5% lignosulfonate (GSL); pelleted sunflower seeds (PS); or ground and pelleted sunflower seeds treated with lignosulfonate (PSL). Four lactating cows with 130±28 days of lactation and body weights of 569±63 kg were used. These animals were distributed in a Latin square design with four diets and four periods of 21 days each. There were no differences in the intakes (% body weight) of dry matter (DM), organic matter (OM), mineral matter (MM), crude protein (CP), neutral detergent fiber (NDF) or acid detergent fiber (ADF). The apparent digestibility of DM, OM, CP, EE, NDF, ADF and NFC were similar for all the diets, with a tendency towards decreased CP digestibility for all the pelleted diets (65.79%) compared with the non-pelleted diets (69.66%). A negative effect of lignosulfonate was observed for the in vitro digestibility (IVD) of DM, and a negative tendency was observed for the IVD of OM. Pelleting decreased the concentration of acetic acid (55.95 × 58.82 mM) in rumen fluid. There was no effect of diet on pH (6.17) or ammonia nitrogen concentration (18.19 mg/dL). Pelleting and lignosulfonate do not promote the protective effect of sunflower seed nutrients as expected, and it may be more feasible to provide ground sunflower seed.
Highlights
The composition, intake and digestibility of dietary nutrients influence the productivity of lactating dairy cows
The objective of this study was to evaluate intake, in vitro and apparent digestibility and ruminal parameters of Holstein cows that were confined and fed corn silage and concentrate containing: ground sunflower seeds (GS); ground sunflower seeds treated with 5% lignosulfonate (GSL); pelleted sunflower seeds (PS); or ground and pelleted sunflower seeds treated with lignosulfonate (PSL)
There were no differences in the intakes (% body weight) of dry matter (DM), organic matter (OM), mineral matter (MM), crude protein (CP), neutral detergent fiber (NDF) or acid detergent fiber (ADF)
Summary
The composition, intake and digestibility of dietary nutrients influence the productivity of lactating dairy cows. The excess fat in ruminant feed, especially those rich in unsaturated fatty acids (UFA) such as those containing sunflower seeds, reduces the digestibility of fiber, the N-NH3 concentration, and the acetate:propionate ratio These effects result either from the toxicity of UFA against gram-positive bacteria, the physical coating of the fiber or the formation of soaps, which especially reduces the production of volatile fatty acids (VFA) (Palmquist & Jenkins, 1980; Jenkins & McGuire, 2006). Upon the addition of 5.1% oil (canola oil, rice and soybeans) to the diets of goats, which consisted of a forage: concentrate ratio of 50:50 and 7.83% fat content, Maia et al (2006) observed no changes in the N-NH3 ruminal concentrations. They observed an increase in the pH, showing that addition of fat may alter ruminal fermentation patterns and microbial activity
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