Effect of Sugar Beet Pulp and Anionic Salts on Metabolic Status and Mineral Homeostasis during the Peri-Parturient Period of Dairy Sheep

Abstract

Sugar beet pulp is a popular by-product of sugar extraction; however, it can potentially cause depletion of Ca availability due to its oxalic content. The experiment examined the effect of sugar beet pulp and anionic salts administration during the dry period on the serum concentration of calcium, magnesium, phosphate, and potassium of dairy sheep. Eighty-seven sheep were divided into three groups (A, B, and C) according to their body condition score (BCS) and age at 40 days before the expected lambing. All groups received alfalfa hay, mixed grass straw, and a concentrate supplement. The concentrate fed to groups B and C contained sugar beet pulp. The nutritional value fed to all three groups was similar, except for Dietary Cation Anion Difference (DCAD). Animals of group A had a DCAD of +198 mEq/kg, animals of group B of +188 mEq/kg, and animals of group C were fed 20 gr/d ammonium chloride to achieve a negative DCAD (−52 mEq/kg). All groups were fed the same ration after lambing. Blood samples were collected 30 d, 20 d, 17 d, 14 d, 10 d, 7 d, and 4 d before lambing (a.p.), 6 h, 12 h, 24 h, 7 d, 10 d, and 15 d after lambing (p.p) for calcium, magnesium, phosphate, and potassium, and 30 d a.p., 7 d, and 15 d p.p. for beta hydroxybutyrate acid (BHBA) concentrations. Urine samples were also collected 20 d, 10 d, 4 d a.p., and 7 d p.p for the evaluation of pH levels. Ca levels of the control group decreased earlier and were lower at 4 d a.p. compared to those of group B and C. Additionally, the control group showed lower p values compared to group C at 20 d and 17 d a.p. P levels recovered earlier post parturition in young (age 1–1.5 years old) compared to older ewes. Group C had lower urine pH values throughout the pre-parturient period, reflecting the acidifying effect of the administered ammonium chloride, without any side effect on macromineral blood concentration. Feeding sugar beet pulp and systemic acidifying before parturition is considered safe and might even be beneficial in preventing hypocalcemia.