Impact of Dry Sugar Beet Pulp on Milk Production, Digestibility Traits, and Blood Constituents of Dairy Holstein Cows

SIMPLE SUMMARY: There are many agriculture by-products in the agriculture sector, and many of them have high socio-economic value. There is a growing interest in recycling agro-industrial by-products for feeding ruminants. Sugar beets are used to produce sugar and result in sugar beet pulp by-products, which can be used as feed for livestock, either as dried flakes or as compressed pellets. In this study, the effect of partial replacement of yellow corn grains (YCG) with dry sugar beet pulp (DSBP) at levels of 25 and 50% was evaluated with respect to the milk production and health condition of dairy Holstein cows. Partial replacement of YCG with DSBP in the rations of dairy cows led to significant improvements in the digestion, rumen activity, plasma biochemical parameters, milk yield, milk composition, feed use, and milk yield. Furthermore, the reduction in feed cost and the increase in milk yield improved with increasing DSBP in the ration. Thus, replacing feed ingredients with DSBP is recommended for feeding dairy Holstein cows with low-cost feeds without reducing their health status and production. ABSTRACT: Thirty multiparous lactating Holstein cows with an average live body weight of 642 ± 21 kg and an average daily milk yield of 30.46 ± 0.59 kg were used in this study. Cows with parities of 2 and 4 were used following their peak period, and were divided into three groups, with ten cows in each group. The control group was fed yellow corn grain rations (YCG), while for the 2nd and 3rd groups, 25 and 50% of YCG was replaced with dry sugar beet pulp (DSBP), denoted as DSBP(25) and DSBP(50), respectively. The contents of dry matter, organic matter, ether extract, nitrogen-free extract, and fiber carbohydrate in the experimental rations tended to decrease; however, crude protein, crude fiber, ash, and fiber fractions tended to increase in the DSBP(25) and DSBP(50) groups. Only crude fiber digestibility increased (p < 0.05) in the DSBP rations. Rumen pH value and concentration of ammonia nitrogen (NH(3)-N) decreased, while the concentration of total volatile fatty acids (TVFAs) increased in the DSBP(25) and DSBP(50) groups. The concentrations of total protein and globulin in blood plasma were higher (p < 0.05) in DSBP(25) and DSBP(50) than in YCG. However, plasma albumin concentration, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) activities were lower (p < 0.05) in DSBP(50) than in YCG. Milk yield and yield of 4% fat-corrected milk (4% FCM) were higher (p < 0.05) in DSBP(25) and DSBP(50) than in YCG. Fat, protein, solids not fat (SNF), and total solids (TS) contents in milk increased significantly (p < 0.05) for feeding rations containing DSBP. Feed cost was reduced, but the output of milk yield increased with DSBP. In conclusion, introducing DSBP into the rations of Holstein dairy cows led to significant improvements in their productive performance.