Postpartum uterine infections affect ovarian function and delay ovulation in cattle. As dietary fats can affect immune cell function, we investigated the influence of prepartum diets on postpartum uterine inflammatory status (UIS) as assessed 25 ± 1 days postpartum by endometrial cytology (normal: ≤8% polymorphonuclear cells (PMN) vs subclinical endometritis (SCE): >8% PMN) and associations between SCE, pro- and anti-inflammatory cytokine gene expression and ovarian function. During the last 5 weeks of gestation, dairy cows received a diet supplemented with 8% rolled sunflower (n = 10) or canola seed (n = 9) or no oilseed (n = 9). Ovaries were scanned until 35 days postpartum. Prepartum diets did not influence SCE, but a preovulatory-size follicle developed sooner (P ≤ 0.05), the interval to first ovulation was shorter and the proportion of cows ovulating within 35 days postpartum was greater in the sunflower seed group. Although mRNA expression of cytokines was not affected by diet, cows with SCE had higher (P ≤ 0.05) expression of interleukin-1β (IL1B), interleukin-8 (CXCL8), IL10 and tumour necrosis factor-α (TNF) than normal cows. The interval (mean ± s.e.m.) from calving to preovulatory-size follicle was shorter (P ≤ 0.05) in normal (13.2 ± 0.9 days) than SCE cows (18.7 ± 1.4 days). In summary, a prepartum diet supplemented with sunflower seed positively influenced postpartum ovarian function without affecting UIS or pro- and anti-inflammatory cytokine gene expression in endometrial cells.
Effects of prepartum oilseed supplements on subclinical endometritis, pro- and anti-inflammatory cytokine transcripts in endometrial cells and postpartum ovarian function in dairy cows
