Laboratory of Theriogenology and Reproductive Health, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 2 Xinyang Road, Sartu District, Daqing 163319, China; Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, No. 2 Xinyang Road Sartu District, Daqing, 163319, China.
Laboratory of Theriogenology and Reproductive Health, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 2 Xinyang Road, Sartu District, Daqing 163319, China.
Anim Reprod Sci. 2020 Jul;218:106481. doi: 10.1016/j.anireprosci.2020.106481. Epub 2020 May 5.
Retained placentae (RP) results in significant economic losses to dairy farmers. In Experiment 1, to screen biochemical indicators of RP, 21 cows with RP and 21 cows with no retained placenta (NRP) were selected as a control group, and blood was collected at -7 d, 0 h (parturition) and 12 h. Serum biochemical indicators were ascertained. Results indicate serum concentrations of phosphorus (P) and blood urea nitrogen (BUN) in cows of the RP group were markedly greater than in cows of the NRP group at -7 d (P < 0.01). In Experiment 2, to evaluate predictive indicators for RP, 34 cows with RP and 34 cows with NRP were selected, and there was blood sampling at -15 d, -10 d, -7 d, -4 d, and -1 d. Serum P, BUN, and total protein (TP) were evaluated. Associations of values among the three indicators and occurrence of RP were analyzed using binary logistic regression. Results indicate there was a negative correlation between only the values for BUN and RP (P = 0.016). In Experiment 3, to test hypothesis that relatively greater concentrations of BUN effects immune function in placental tissues, four cows were selected, placentae were collected at 0 and 12 h, and hematoxylin-eosin (HE) staining was performed. Results indicated that the extent of inflammatory cell infiltration and vascular proliferation were less at the 12 than 0-hour timepoint. Taken together, BUN at -7 d may serve as a predictive indicator of RP in cows.
胎衣不下（RP）会给奶牛养殖户造成巨大的经济损失。在实验 1 中，为了筛选 RP 的生化指标，选择了 21 头 RP 奶牛和 21 头无胎衣不下（NRP）奶牛作为对照组，分别在-7d、0h（分娩）和 12h 采集血液。测定血清生化指标。结果表明，RP 组奶牛血清磷（P）和血尿素氮（BUN）浓度在-7d 时明显高于 NRP 组（P<0.01）。在实验 2 中，为了评估 RP 的预测指标，选择了 34 头 RP 奶牛和 34 头 NRP 奶牛，在-15d、-10d、-7d、-4d 和-1d 采血。评估血清 P、BUN 和总蛋白（TP）。采用二项逻辑回归分析这三个指标值之间的关系与 RP 的发生。结果表明，只有 BUN 值与 RP 呈负相关（P=0.016）。在实验 3 中，为了检验 BUN 浓度相对较高会影响胎盘组织免疫功能的假设，选择了 4 头奶牛，在 0 小时和 12 小时采集胎盘，进行苏木精-伊红（HE）染色。结果表明，在 12 小时时，炎症细胞浸润和血管增生的程度比 0 小时时小。综上所述，-7d 的 BUN 可能是奶牛 RP 的预测指标。
