Livestock Systems Section, Alberta Agriculture and Forestry, Edmonton, T6H 5T6, Canada.
Department of Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, S7N 5B4, Canada.
Theriogenology. 2020 Jul 15;151:52-57. doi: 10.1016/j.theriogenology.2020.03.034. Epub 2020 Apr 1.
The objective of this study was to examine the relationship between early postpartum nutritional and metabolic profiles in lactating dairy cows and subsequent pregnancy to first artificial insemination (AI), pregnancy by 150 d in milk (DIM) and pregnancy loss after first AI. A blood sample was collected between 2 and 14 (median = 9) DIM from 869 lactating Holstein cows to determine serum concentrations of metabolites, minerals, and liver enzymes. Associations between analytes and fertility were determined using an adjusted odds ratio (OR). Overall, pregnancy to first AI, pregnancy by 150 DIM and pregnancy loss after first AI were 37.9, 65.8 and 11.2%, respectively. Compared to cows pregnant to first AI, non-pregnant cows had higher (P < 0.05) serum concentrations of aspartate aminotransferase (AST; 92.3 ± 1.6 vs. 84.6 ± 2.0 U/L), non-esterified fatty acid (NEFA; 0.73 ± 0.02 vs. 0.54 ± 0.02 mmol/L), and haptoglobin (0.77 ± 0.04 vs. 0.60 ± 0.05 g/L), and lower (P < 0.05) serum concentrations of Mg (0.86 ± 0.02 vs. 0.89 ± 0.02 mmol/L) and cholesterol (2.1 ± 0.03 vs. 2.4 ± 0.04 mmol/L). Cows non-pregnant by 150 DIM had lower (P < 0.05) serum concentration of Mg (0.86 ± 0.02 vs. 0.88 ± 0.02 mmol/L) and higher serum concentration of haptoglobin (0.82 ± 0.1 vs. 0.63 ± 0.09 g/L) than cows pregnant by 150 DIM. Cows that lost their pregnancy after first AI had greater serum concentrations of haptoglobin than those that did not undergo pregnancy loss (1.1 ± 0.09 vs. 0.5 ± 0.05 g/L; P < 0.01). The odds of pregnancy to first AI (OR; 95% confidence interval [CI]) decreased with increased serum concentrations of AST (OR = 0.99; 95% CI = 0.98-1.00), NEFA (OR = 0.54; 95% CI = 0.37-0.79) and haptoglobin (OR = 0.80; 85% CI = 0.66-0.96) and increased with inreased concentrations of Mg (OR = 3.24; 95% CI = 1.09-9.62) and cholesterol (OR = 1.24; 95% CI = 1.02-1.54). Increased serum concentrations of Mg (OR = 3.06; 95% CI = 1.02-9.20) and haptoglobin (OR = 0.92; 95% CI = 0.69-0.97) were associated with greater and lower odds of pregnancy by 150 DIM, respectively. Only increased concentrations of haptoglobin (OR = 1.58; 95% CI = 1.13-2.20) were associated with increased odds of pregnancy loss after the first AI. In summary, greater early postpartum serum concentrations of AST, NEFA and haptoglobin were associated with reduced fertility, but the opposite was observed for serum concentrations of Mg and cholesterol. In addition, serum concentrations of haptoglobin were positively associated with pregnancy loss.
本研究旨在探讨泌乳奶牛产后早期营养和代谢状况与随后的首次人工授精（AI）妊娠、产后 150 天（DIM）妊娠和首次 AI 后妊娠损失之间的关系。从 869 头荷斯坦泌乳奶牛中采集了产后 2 至 14 天（中位数=9 天）的血样，以确定血清代谢物、矿物质和肝酶的浓度。使用调整后的优势比（OR）确定分析物与生育力之间的关系。总的来说，首次 AI 妊娠、产后 150 天妊娠和首次 AI 后妊娠损失的比例分别为 37.9%、65.8%和 11.2%。与首次 AI 妊娠的奶牛相比，未妊娠的奶牛血清中天冬氨酸转氨酶（AST；92.3±1.6 与 84.6±2.0 U/L）、非酯化脂肪酸（NEFA；0.73±0.02 与 0.54±0.02mmol/L）和触珠蛋白（0.77±0.04 与 0.60±0.05g/L）浓度更高（P<0.05），镁（0.86±0.02 与 0.89±0.02mmol/L）和胆固醇（2.1±0.03 与 2.4±0.04mmol/L）浓度更低（P<0.05）。产后 150 天未妊娠的奶牛血清镁浓度较低（P<0.05）（0.86±0.02 与 0.88±0.02mmol/L），触珠蛋白浓度较高（0.82±0.1 与 0.63±0.09g/L）。与未发生妊娠损失的奶牛相比，首次 AI 后妊娠损失的奶牛血清触珠蛋白浓度更高（1.1±0.09 与 0.5±0.05g/L；P<0.01）。首次 AI 妊娠的可能性（OR；95%置信区间[CI]）随 AST 血清浓度的增加而降低（OR=0.99；95%CI=0.98-1.00）、NEFA（OR=0.54；95%CI=0.37-0.79）和触珠蛋白（OR=0.80；95%CI=0.66-0.96），随镁浓度的增加而增加（OR=3.24；95%CI=1.09-9.62）和胆固醇（OR=1.24；95%CI=1.02-1.54）。血清镁浓度的增加（OR=3.06；95%CI=1.02-9.20）和触珠蛋白（OR=0.92；95%CI=0.69-0.97）分别与 150 天妊娠的可能性增加和降低相关。只有触珠蛋白浓度的增加（OR=1.58；95%CI=1.13-2.20）与首次 AI 后妊娠损失的可能性增加相关。总之，AST、NEFA 和触珠蛋白的早期产后血清浓度升高与生育力降低有关，但镁和胆固醇的血清浓度则相反。此外，触珠蛋白的血清浓度与妊娠损失呈正相关。
