اثر جایگزینی تفاله چغندر قند با دانه جو در جیره گاوهای با نمره وضعیت بدنی بالا در اواخر دوره شیردهی بر توان تولیدی، نمره وضعیت بدنی و متابولی تهای خون

In order to examine the effects of increasing concentrations of beet pulp (lipogenic nutrient) substituted for barley grain (glycogenic nutrient) on productive performance, body condition score loss, and blood metabolites, 18 Holstein cows were used in a randomized complete block design. The cows were blocked based on parity. The cows were 171 ± 16 d in pregnancy, 2.76 ± 1.14 parity, and 289 ± 35 d in milk at the beginning of the experiment. The cows' body condition scores were 4.12 ± 0.35 at the beginning of the trial. The cows were assigned randomly to three dietary treatments containing 1) 23.47% barley (0% beet pulp), 2) 14.87% barley (8.6% beet pulp), or 3) 6.27% barley (17.2% beet pulp). Substituting beet pulp for barley grain didn't affect FCM 3.5%, milk protein, lactose, total solid, and SNF percentage, but milk fat percentage (4.37, 4.91, and 5.18, P < 0.003) and milk energy (0.76, 0.82, and 0.84 Mcal/kg, P < 0.02) increased as beet pulp was replaced with barley, respectively. A tendency was detected for a more negative body condition score change (0.13, -0.09, and -0.12, P < 0.13) and back fat thickness (2.5, -0.4, and -1.6 mm, P < 0.13) with added beet pulp. Plasma glucose (65.83, 58, and 57.16 mg/dl, P < 0.01) and cholesterol (157.33, 122.4, and 120.8 mg/dl, P < 0.03) decreased as beet pulp was substituted for barley grain, respectively. No difference was found in the plasma content of insulin and NEFA between treatments. Considering these results, it appears that with inclusion of beet pulp in fat cows diet during late lactation may slightly reduce body condition score safely and inhibit concomitant low production with diet diluting.