Effects of prepartum oilseed supplements on subclinical endometritis, pro- and anti-inflammatory cytokine transcripts in endometrial cells and postpartum ovarian function in dairy cows.

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-1ß (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.

Morphologic and transcriptomic assessment of bovine embryos exposed to dietary long-chain fatty acids.

The main objectives of this study were to determine the influence of diets enriched in α-linolenic, linoleic or oleic acid on the development and transcriptomic profile of embryos collected from dairy cattle. Non-lactating Holstein cows received one of the three diets supplemented with 8% rolled oilseeds: flax (FLX, n = 8), sunflower (SUN, n = 7) or canola (CAN, n = 8). After a minimum 35-day diet adaptation, cows were superovulated, artificially inseminated and ova/embryos recovered non-surgically after 7.5 days. Cows fed FLX had less degenerated embryos and more viable embryos than those fed CAN or SUN. In total, 175 genes were differentially expressed in blastocysts from cows fed FLX than in cows fed CAN or SUN. These differentially expressed genes were mainly involved in cellular growth and proliferation, cellular development, and cell survival and viability. In conclusion, dietary n-3 polyunsaturated fatty acids reduced early embryonic degeneration possibly through improving embryonic cell survival and viability.

A prepartum diet supplemented with oilseeds high in oleic or linoleic acid reduced GnRH-induced LH release in dairy cows during second week postpartum.

BACKGROUND: The objective was to determine the effect of prepartum diets supplemented with rolled canola seed (high in oleic acid) or sunflower seed (high in linoleic acid) on luteinizing hormone (LH) pulsatility and gonadotropin releasing hormone (GnRH)-induced LH release during early postpartum. METHODS: Thirty-one pregnant Holstein cows, blocked by body condition score, parity and expected calving date, were assigned to 1 of 3 prepartum diets supplemented with 8 % rolled canola or sunflower seed, or no oilseed (control) during the last 35 d of gestation. Blood samples were collected at Weeks (wk)-3, 0, +1 and +2, relative to calving, to determine non-esterified fatty acids (NEFA), Beta-hydroxy butyric acid (BHBA) and glucose. Additional blood samples were collected during wk1 (n = 5 per treatment) or wk2 (n = 5 or 6 per treatment), for 6 h, to measure LH pulsatility; thereafter, 100 mcg GnRH was administrated i.m., and blood was sampled for 4 h more, to measure GnRH-induced LH release. RESULTS: Dietary treatment did not affect prepartum energy balance, but cows fed the control diet were in a deeper state of negative energy balance during wk2, than those fed canola (P = 0.03) or sunflower (P = 0.01). Prepartum diets did not influence the mean plasma concentration of BHBA and glucose. However, NEFA concentration during wk2 was greater in control cows than those fed sunflower (P = 0.03) or canola (P = 0.07). Prepartum diets did not affect LH pulsatility (i.e. mean, minimum, maximum concentration, pulse frequency, and amplitude during wk1 and 2). GnRH-induced LH release did not differ among dietary treatments during wk1 but the mean GnRH-induced LH release during wk2 was either greater (P = 0.02) and tended to be greater (P = 0.09) in control cows than in those fed canola and sunflower, respectively. CONCLUSIONS: Prepartum diets did not affect LH pulsatility and GnRH-induced LH release during the first week postpartum, but cows fed a diet supplemented with oilseeds high in oleic or linoleic acid released less LH than control cows, in response to an exogenous GnRH challenge during the second week postpartum.