To determine the optimum feeding level of fatty acids of palm oil (PALM; Energizer RP10; 86.6% palmitic acid) on milk production, lactating cows (n = 18) were randomly assigned to a treatment sequence in replicated 4 x 4 Latin squares. Animals were assigned to squares by parity (3 multiparous and 1 primiparous squares with primiparous in the incomplete square). The 4 diets were designed to provide 0, 500, 1,000, and 1,500 g of PALM per day. Cows were fed individually with feed intake measured daily. Each period lasted 16 d with milk production and composition determined the final 2 d. Milk production, milk composition and feed intake data were analyzed using the MIXED procedure of SAS. Milk yields were 30.9, 34.0, 34.2, and 34.2 kg/ d (SEM = 1.9) for the 0, 500, 1,000, and 1,500 g levels, respectively. Milk yield was increased by the addition of PALM; however, there were no differences among the levels of PALM. Milk fat percentage was also increased from 3.44% for 0 g to 3.95% (SEM = 0.17) across all levels of PALM but there were no differences among the PALM treatments. Dry matter intakes were 23.3, 26.4, 24.7, and 23.8 kg/d (SEM = 1.4) for the 0, 500, 1,000 and 1,500 g levels, respectively. The addition of PALM increased milk yield and milk fat percentage, and no adverse effects on dry matter intake were observed.

Immune system and inflammatory responses are affected by α-linolenic acid (αLA: 18:3 ω-3). The objective of this study was to determine the effects of αLA-enriched rations on gene expression of systemic (blood) and local (mammary gland) inflammatory markers in Holstein dairy cattle. Further, the effect of dietary treatments was evaluated on the concentration of αLA in serum phospholipids. Camelina (Camelina sativa) meal (containing 24.2% αLA) was fed at 0, 3, 6, and 9% (dry matter basis) replacing canola meal (rich in 18:1 ω-9) to provide rations with incremental concentrations of αLA. Lactating primiparous Holstein cows (n = 18) were randomly assigned to a treatment sequence in a 4 × 4 Latin square design. Each period lasted 16 d and milk and blood samples were collected during the final 2 d of each period. Peripheral blood mononuclear cells (PBMC) and milk cells (MC) were harvested, and RNA extracted and converted to complementary DNA for quantitative real time PCR analysis. The effect of dietary treatments (αLA) on the relative abundance of pro- and anti-inflammatory genes in the PBMC and MC was tested by the MIXED procedure of SAS. Expression of pro-inflammatory tumour necrosis factor (TNF)-α in MC was linearly reduced (up to 40%) as dietary αLA increased. Expression of pro-inflammatory markers interleukin (IL)-1β, IL-8, and TNF-α was reduced (29, 20, and 27%, respectively) in PBMC isolated from cows fed 6% camelina meal ration as compared with cows fed 0% (control). Expression of IL-6 was, however, increased with inclusion of camelina meal. Greater dietary αLA linearly increased serum phospholipids αLA contents, and when fed up to 6% DM down-regulated expression of some of the local (milk) and systemic (blood) pro-inflammatory markers in vivo.

α‐linolenic acid (αLA) is an essential fatty acid that functions in the maintenance of cell membrane fluidity and the synthesis of eicosanoids. This study examined the effect of an αLA‐enriched feed (camelina meal) on mRNA expression of lipid metabolism genes in somatic cells harvested from milk. Primiparous dairy cows (n=18) were fed a ration containing 0, 3, 6, and 9% camelina meal substituting for canola meal (18:1 cis9) in a 4x4 Latin square design. Somatic cells (primarily leukocytes and epithelial cells) were separated out of milk and total RNA was extracted for gene expression analysis with real time rt‐PCR. Expression of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS), lipoprotein lipase and stearoyl CoA desaturase was increased in milk cells with the 6% diet whereas milk fat percent and yield were decreased. A negative correlation was observed between the concentrations of serum triglycerides and expression of ACC and FAS whereas a positive correlation was observed between the concentrations of serum non‐esterified fatty acids and expression of the same two genes. More research is needed to elucidate the relationship between mRNA expression of lipid metabolism genes in milk somatic cells and serum lipid content. Use of total milk somatic cells may not be an accurate method of measuring mammary epithelial cell mRNA expression. Supported by the United Dairymen of Idaho and NIH‐NRRI grant P20 RR15587.

α‐linolenic acid (αLA: 18:3 ?3) affects inflammatory responses. The objective of this study was to investigate the effects of αLA‐enriched rations on gene expression of systemic (blood) and local (mammary gland) inflammatory markers in dairy cattle. Camelina (camelina sativa) meal (24.2% αLA) was fed at 0, 3, 6, and 9% (DM basis) replacing canola meal (18:1 ω‐9) to provide rations with incremental concentrations of αLA. Lactating primiparous cows (n=18) were randomly assigned to a treatment sequence in a 4x4 Latin square design. Each period lasted 16 d and milk and blood samples were collected during the final 2 d of each period. Peripheral blood mononuclear (PBMC) and milk cells (MC) were harvested, and RNA extracted and converted to cDNA for quantitative real time PCR analysis. Expression of pro‐inflammatory TNF‐α in MC was linearly reduced (up to 40%) as dietary αLA increased. Expression of pro‐inflammatory markers IL‐1β, IL‐8, and TNF‐α was reduced (29, 20, and 27%, respectively) in PBMC isolated from cows fed 6% camelina meal ration as compared with cows fed 0%. Expression of IL‐6 was, however, increased as dietary αLA increased. Further, mRNA expression of TGF‐β in PBMC was decreased. Dietary αLA linearly increased serum phospholipids and milk αLA contents, and down‐regulated expression of local and systemic pro‐inflammatory markers. Supported by the United Dairymen of Idaho and NIH‐NRRI grant P20 RR15587.