Guadagnin A R, Cardoso F C
Department of Animal Sciences, University of Illinois, Urbana, IL 61801.
Department of Animal Sciences, University of Illinois, Urbana, IL 61801.
J Dairy Sci. 2023 Oct;106(10):7240-7265. doi: 10.3168/jds.2022-23070. Epub 2023 Jul 31.
Dry matter intake (DMI, kg/d) is closely related to the magnitude of negative energy and protein balance during the transition period, and the metabolic adaptations to support lactation in dairy cows. Thus, DMI might affect the development of cytological endometritis in the early postpartum period. Difficulty to adapt to these metabolic changes is related to impaired immune function and increased occurrence of reproductive disorders. We aimed to examine the association of pre- and postpartum DMI, body weight (BW), body condition score, milk yield and milk composition, and days to first ovulation with cytological endometritis at 15 (CYT15) and 30 DIM (CYT30). A second objective was to understand the association of vaginal discharge with CYT15 and CYT30 and performance. We conducted a pooled statistical analysis of 5 studies, including data from 280 multiparous Holstein cows. Based on the cutoffs for the percentage of uterine polymorphonuclear cells (PMN), determined by taking the median value of the data set for 15 and 30 DIM, cows were categorized as follows: LOW15 (PMN % at 15 DIM ≤24%; n = 125), HIGH15 (PMN % at 15 DIM >24%; n = 125), LOW30 (PMN % at 30DIM ≤7%; n = 141); and HIGH30 (PMN % at 30DIM >7%; n = 139). Cows in HIGH15 consumed an average of 1.97 ± 0.5 kg/d less DM than cows in LOW15 during prepartum, and 3.01 ± 0.5 kg/d less DM during postpartum. Dry matter intake (as a percentage of BW) was higher for cows in LOW15 during pre- and postpartum than for cows in HIGH15. Moreover, cows in HIGH15 tended to have lower milk yield than cows in LOW15 from the third until the fifth week postpartum. Although DMI was not associated with CYT30, DMI (as a percentage of BW) was lower for cows in LOW30 pre- and postpartum than for cows in HIGH30. There was no association between CYT30 and milk yield. Cows in LOW15 had greater days to first ovulation than cows in HIGH15, while cows in LOW30 also had greater days to first ovulation than cows in HIGH30. Simple regression analyses demonstrated linear associations of increased DMI, particularly postpartum, with decreased uterine PMN percentage and lower vaginal discharge score. Additionally, increased units of vaginal discharge score and increased percentage units of uterine PMN were linearly associated with decreased milk yield. Corroborating with the notion of the ovarian function being associated with uterine inflammatory status, cows in HIGH15 and HIGH30 ovulated on average 3 d before than cows in LOW15 and LOW30, respectively. Cytological endometritis at 15 DIM was associated with lower DMI from 4 wk before calving until 4 wk postpartum and was associated with lower milk yield. The association of vaginal discharge with cytological endometritis was variable and dependent on the day of evaluation.
干物质采食量（DMI，千克/天）与围产期负能量和蛋白质平衡的程度以及奶牛泌乳的代谢适应性密切相关。因此，DMI可能会影响产后早期细胞学子宫内膜炎的发生发展。难以适应这些代谢变化与免疫功能受损和生殖障碍发生率增加有关。我们旨在研究产前和产后的DMI、体重（BW）、体况评分、产奶量和乳成分以及首次排卵天数与15天（CYT15）和30天产犊间隔（CYT30）时的细胞学子宫内膜炎之间的关联。第二个目标是了解阴道分泌物与CYT15和CYT30及生产性能之间的关联。我们对5项研究进行了汇总统计分析，包括来自280头经产荷斯坦奶牛的数据。根据子宫多形核细胞（PMN）百分比的临界值，通过取15天和30天产犊间隔数据集的中位数来确定，奶牛被分类如下：LOW15（15天产犊间隔时PMN%≤24%；n = 125）、HIGH15（15天产犊间隔时PMN%>24%；n = 125）、LOW30（30天产犊间隔时PMN%≤7%；n = 141）；和HIGH30（30天产犊间隔时PMN%>7%；n = 139）。在产前，HIGH15组奶牛的平均DMI比LOW15组奶牛少1.97±0.5千克/天，产后少3.01±0.5千克/天。产前和产后，LOW15组奶牛的干物质采食量（占BW的百分比）高于HIGH15组奶牛。此外，从产后第三周到第五周，HIGH15组奶牛的产奶量往往低于LOW15组奶牛。虽然DMI与CYT30无关，但产前和产后LOW30组奶牛的DMI（占BW的百分比）低于HIGH30组奶牛。CYT30与产奶量之间没有关联。LOW15组奶牛的首次排卵天数比HIGH15组奶牛多，而LOW30组奶牛的首次排卵天数也比HIGH30组奶牛多。简单回归分析表明，DMI增加，尤其是产后DMI增加，与子宫PMN百分比降低和阴道分泌物评分降低呈线性相关。此外，阴道分泌物评分单位增加和子宫PMN百分比单位增加与产奶量降低呈线性相关。与卵巢功能与子宫炎症状态相关的观点一致，HIGH15组和HIGH30组奶牛分别比LOW15组和LOW30组奶牛平均早3天排卵。15天产犊间隔时的细胞学子宫内膜炎与产犊前4周直至产后4周的较低DMI有关，并且与较低的产奶量有关。阴道分泌物与细胞学子宫内膜炎的关联是可变的，并且取决于评估的天数。
