Animal Production Department, Faculty of Agriculture, Kafrelsheikh University, Kafr El Sheikh, Egypt.
Department of Veterinary Sciences, Texas Tech University, Lubbock, TX, USA.
Anim Sci J. 2022 Jan-Dec;93(1):e13715. doi: 10.1111/asj.13715.
We determined effects of pre- and postpartum dietary cation-anion difference (DCAD) on urine pH, serum calcium and hormone concentrations, and milk production with 48 multiparous Holstein cows (average body weight = 706 ± 7.3 kg). Treatments were 3 prepartum DCAD concentrations (0, -100, or -180 mEq/kg dry matter [DM]) and 2 postpartum DCAD concentrations (+250 or +350 mEq/kg DM) starting 29 days before parturition through 90 days in milk. Prepartum urine pH was lower (p < 0.05) for -180 than for -100 or 0 DCAD, and postpartum urine pH was higher (p < 0.05) for +350 than for +250 DCAD. Prepartum serum total and ionized calcium and hydroxyproline were greater (p < 0.05) for -180 than for -100 and 0 DCAD, whereas parathyroid hormone was greater (p < 0.05) for 0 than for -100 and -180 DCAD. After calving, negative prepartum DCAD increased (p < 0.05) serum total and ionized calcium, but effects varied by sampling day. Pre- and postpartum DCAD did not affect milk yield or milk fat, but milk protein percent and total solids were increased (p < 0.05) by negative prepartum DCAD. Feeding an acidogenic diet prepartum improved postpartum calcium status without major effects on milk yield and composition.
我们研究了产前和产后日粮阴阳离子差（DCAD）对尿液 pH 值、血清钙和激素浓度以及产奶量的影响，试验选用了 48 头经产荷斯坦奶牛（平均体重为 706 ± 7.3 kg）。试验采用 3 种产前 DCAD 浓度（0、-100 或-180 mEq/kg 干物质（DM））和 2 种产后 DCAD 浓度（+250 或+350 mEq/kg DM），从分娩前 29 天开始至泌乳 90 天结束。产前尿液 pH 值，-180 DCAD 组显著低于-100 和 0 DCAD 组（p<0.05），产后尿液 pH 值，+350 DCAD 组显著高于+250 DCAD 组（p<0.05）。产前血清总钙和离子钙及羟脯氨酸含量，-180 DCAD 组显著高于-100 和 0 DCAD 组（p<0.05），甲状旁腺激素含量，0 DCAD 组显著高于-100 和-180 DCAD 组（p<0.05）。产后，负的产前 DCAD 显著增加（p<0.05）血清总钙和离子钙含量，但不同采样日之间的影响存在差异。产前和产后 DCAD 对产奶量和乳脂没有影响，但负的产前 DCAD 显著提高（p<0.05）乳蛋白率和总固体含量。产前饲喂酸性日粮改善了产后钙的状况，但对产奶量和组成没有重大影响。
