Department of Animal Sciences, University of Florida, Gainesville, 32611; DH Barron Reproductive and Perinatal Biology Research Program, University of Florida, Gainesville, 32611.
Department of Animal Sciences, University of Florida, Gainesville, 32611.
J Dairy Sci. 2021 Aug;104(8):8746-8764. doi: 10.3168/jds.2021-20483. Epub 2021 May 28.
The objectives were to determine the effects of dietary cation-anion difference (DCAD) fed to pregnant cows during the last 22 d of gestation on offspring acid-base balance, metabolism, growth, and health preweaning. A total of 132 nulliparous Holstein cows were enrolled at 250 (248 to 253) d of gestation in a randomized block design. Cows were blocked by genomic merit of energy-corrected milk yield and assigned randomly to diets varying in DCAD: +200 (P200, n = 43), -50 (N50, n = 45), or -150 (N150, n = 44) mEq/kg of dry matter (DM). Newborn calves (15 males and 28 females in P200, 22 males and 23 females in N50, and 18 males and 26 females in N150) were followed for the first 7 or 56 d of age if males or females, respectively. Measures of acid-base balance and concentrations of minerals in blood were measured in all calves on d 0 before colostrum feeding, and on d 1, 3, and 7. Each calf was fed 3.78 L of colostrum from the respective treatment, and apparent efficiency of IgG absorption was determined. All calves were weighed at birth, and females were weighed again at 21, 42, and 56 d of age. Concentrations in serum of total calcium (tCa), total magnesium (tMg), and total phosphorus (tP) were measured up to 56 d of age; intakes of milk and starter grain DM were measured daily from 21 to 56 d of age; and incidence of disease was recorded for the first 56 d of age in females. Treatment did not affect acid-base balance measured in all calves. Calves were born with metabolic and respiratory acidosis, which reversed by 1 d of age. In the first 24 h after birth, blood pH increased from 7.215 to 7.421 and bicarbonate from 26.2 to 31.7 mM, whereas partial pressure of CO decreased from 64.1 to 48.7 mm of Hg in all treatments. Maternal DCAD did not affect colostrum IgG content fed to calves (P200 = 95.0 vs. N50 = 91.0 vs. N150 = 97.1 ± 4.1 g/L) or apparent efficiency of IgG absorption (P200 = 33.1 vs. N50 = 33.1 vs. N150 = 34.2 ± 1.9%). Males were born heavier than females, but maternal DCAD did not affect birth weight of all calves (P200 = 37.7 vs. N50 = 37.3 vs. N150 = 37.8 ± 0.7 kg) or daily weight gain in females in the first 56 d of life (P200 = 0.80 vs. N50 = 0.81 vs. N150 = 0.77 ± 0.03 kg/d). Treatment did not affect intake of milk (P200 = 1.11 vs. N50 = 1.04 vs. N150 = 1.19 ± 0.06 kg/d) or starter grain DM (P200 = 0.27 vs. N50 = 0.27 vs. N150 = 0.21 ± 0.06 kg/d), or measures of feed efficiency. Treatment did not affect concentrations of minerals in serum, morbidity, or age at morbidity. Manipulating the DCAD of pregnant nulliparous dams during late gestation did not affect offspring performance in the first 2 mo of age.
本研究旨在确定妊娠最后 22 天期间母牛饲粮阴阳离子差（DCAD）对仔牛酸碱平衡、代谢、生长和健康的影响。132 头初产荷斯坦奶牛于妊娠 250 天（248 至 253 天）进入随机分组设计。奶牛按产奶量校正后的能量基因组优势分为组块，然后随机分配到饲粮 DCAD 水平：+200（P200，n = 43）、-50（N50，n = 45）或-150（N150，n = 44）mEq/kg 干物质（DM）。如果是雄性，则从新生犊牛（P200 中 15 头雄性和 28 头雌性，N50 中 22 头雄性和 23 头雌性，N150 中 18 头雄性和 26 头雌性）中随机选择 15 头雄性和 28 头雌性，或如果是雌性，则从新生犊牛中随机选择 22 头雄性和 23 头雌性，在出生后第 7 或 56 天进行跟踪。在出生前初次采食初乳时（第 0 天），以及第 1、3 和 7 天，所有犊牛均进行酸碱平衡和血液矿物质浓度的测定。每个犊牛都接受了来自各自处理的 3.78L 初乳，并且测定了 IgG 吸收的表观效率。所有犊牛在出生时称重，雌性犊牛在 21、42 和 56 日龄时再次称重。在 56 日龄时，血清总钙（tCa）、总镁（tMg）和总磷（tP）的浓度进行了测定；21 至 56 日龄时，每天测定牛奶和开食料 DM 的摄入量；在 56 日龄之前，记录雌性犊牛的疾病发生率。处理对所有犊牛的酸碱平衡没有影响。犊牛出生时存在代谢性和呼吸性酸中毒，出生后 1 天内恢复正常。出生后 24 h 内，血液 pH 值从 7.215 增加到 7.421，碳酸氢盐从 26.2 增加到 31.7 mM，而所有处理的二氧化碳分压从 64.1 降低到 48.7 mm Hg。母体 DCAD 不影响犊牛的初乳 IgG 含量（P200 = 95.0 vs. N50 = 91.0 vs. N150 = 97.1 ± 4.1 g/L）或 IgG 吸收的表观效率（P200 = 33.1 vs. N50 = 33.1 vs. N150 = 34.2 ± 1.9%）。雄性犊牛出生时比雌性犊牛重，但母体 DCAD 不影响所有犊牛的出生体重（P200 = 37.7 vs. N50 = 37.3 vs. N150 = 37.8 ± 0.7 kg）或雌性犊牛在生命的前 56 天的日增重（P200 = 0.80 vs. N50 = 0.81 vs. N150 = 0.77 ± 0.03 kg/d）。处理不影响牛奶（P200 = 1.11 vs. N50 = 1.04 vs. N150 = 1.19 ± 0.06 kg/d）或开食料 DM（P200 = 0.27 vs. N50 = 0.27 vs. N150 = 0.21 ± 0.06 kg/d）的摄入量，或饲料效率的衡量标准。处理不影响血清矿物质浓度、发病率或发病年龄。在妊娠后期操纵初产母牛的 DCAD 不会影响仔牛在生命前 2 个月的生长性能。
