Effect of dietary starch source on milk production and composition of lactating Holstein cows

Abstract

The objective of this study was to evaluate the effects of four sources of starch on milk production and composition, nutrient digestion and blood metabolites of lactating Holstein cows. Four multiparous Holstein cows (708 ± 70 kg of body weight; 83 ± 9 days in milk) were used in a 4 × 4 Latin square design with 21-d periods. The concentrate portion of the diet contained wheat, barley, maize or potato as the primary source of starch. Intake of dry matter (DM) ranged from 18.7 kg/d to 19 kg/d, and was similar among treatments. Milk production was higher in cows fed the wheat-based diet compared with other diets while the milk fat concentration of the cows fed the maize-based diet was the highest. Milk protein concentration was unaffected by the source of dietary starch. Cows fed the potato-based diet had a lower milk protein, lactose and solid-non-fat yield. Milk yield/kg of DM intake and net energy for lactation (NE L )/NE L intake were higher in cows fed wheat-, barley-or maize-based diets compared with those fed the potato-based diet. Feed nitrogen efficiency was higher in cows fed the maize-based diet compared with the other experimental diets. Total tract apparent digestibility of organic matter, crude protein and ether extract were higher in cows fed the wheat-or maize-based diets compared with those fed barley-or potato-based diets; however, total tract apparent digestibility of neutral detergent fibre and acid detergent fibre were higher in cows fed the wheatbased diet compared with those fed the potato-based diet. These results showed that improved production performance in cows fed the wheat-based diet appeared to be because of greater nutrient digestibility and greater nutrient utilization efficiency. Furthermore, potato starch is not superior to grain starch as a readily available energy source for lactating dairy cows. ________________________________________________________________________________

Starch in ruminant diets: a review

“…The lower rate of starch degradation could have released more fat precursors. Mosavi et al (2012) also observed slower ruminal degradation for corn starch compared with wheat, barley or potato, as well as increased acetate and butyrate production along with higher milk fat (3.43% vs. 3.12, 3.09, and 3.13%, respectively). Contrary to these findings, Chanjula et al (2004) did not observe differences in milk production and compositional quality by adding corn (low degradability) or cassava (high degradability) at two inclusion levels (55 vs. 75%).…”

“…This rate varies with grain type and processing and generally occurs in the following order: wheat (32% h) > oat > barley (29% h) > potato (5% h) > corn (2% h) and sorghum (Callison et al, 2001;Mosavi et al, 2012). Krause et al (2002) reported lower ruminal pH in lactating cows fed high moisture corn vs. dried corn.…”

“…Mosavi et al (2012) compared milk yield in Holstein cows consuming wheat, barley, maize or potatoes. They found a reduced milk yield for the diet added with potatoes, and attributed it to its lower digestibility.…”

“…Therefore, when dietary energy increases, metabolizable protein is also increased. Mosavi et al (2012) evaluated the effect of four starch sources on milk protein in Holstein cows. While protein levels of milk were similar (3.03, 3.10, 3.14, and 3.04%) for wheat, barley, corn and potato supplements, respectively, milk protein differed in favor of wheat, barley and corn, compared to potato (1.08, 1.06, 1.06, and 0.98 Kg/d, respectively; p = 0.02).…”

Pre- and postpartum effects of starch and fat in dairy cows: A review

“…Glucogenic-based ingredients consist of cereal grains and their milling by-products, molasses, beet and citrus pulps, roots and tubers such as cassava and potatoes and their by-products, and dried reclaimed bakery products (McDonald et al, 2002;Mosavi et al, 2012;Steyn et al, 2017). Fat increases the energy density of the diet (Schroeder et al, 2004), and in particular enhances plasma cholesterol, the major precursor for steroidogenesis, including luteal P 4 synthesis in postpartum cows .…”