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Supplementary dietary plant oils have the potential to alter milk fatty acid composition in ruminants as a result of changes in the amount and kind of fatty acid precursors. We hypothesized that linseed oil in combination with malate (a key propionate precursor in the rumen) would increase ∆9 unsaturated fatty acids and specific gene expression in somatic cells and mammary glands of lactating goats. Twelve lactating goats were used in a 3 × 3 Latin square design. Treatments included the basal diet (CON), the CON plus 4% linseed oil (LO), and the CON plus 4% linseed oil and 2% -malate (LOM). Relative to CON, the LO and LOM supplements increased the daily intake of palmitic (16:0), stearic (18:0), oleic (18:1-9), linoleic (18:2-6), α-linolenic (18:3-3), and γ-linolenic acids (18:2-6); α-linolenic acid intake was increased over 9-fold, from 6.77 to over 51 g/d (0.02). The LO and LOM supplements increased daily milk yield, milk fat yield, and milk fat percentage (0.05). The LOM supplement also increased milk lactose percentage and daily yield ( = 0.03). Both the LO and LOM supplements increased plasma glucose and total cholesterol and decreased plasma β-hydroxbutyrate concentrations ( = 0.03). The LO and LOM supplements increased concentrations of stearic acid; -vaccenic acid (TVA; 18:1-11); -9, -11 CLA; -10 -12 CLA; and α-linolenic acid in rumen fluid and increased the concentrations of oleic acid; TVA; -9, -11 CLA; -10, -12 CLA; and α-linolenic acid in plasma lipids and milk fat (0.05). Conversely, the LO and LOM supplements decreased short- and medium-chain SFA, including lauric (12:0), myristic (14:0), and palmitic acids, in plasma and milk fat (0.05). Relative mRNA levels for and () gene expression were increased in somatic cells and mammary gland tissue by LO and LOM (0.05). We conclude that the higher intake and ruminal production of stearic acid promoted SCD gene expression in somatic cells and mammary tissue. Furthermore, milk somatic cells are a suitable substitute for documenting treatment effects of dietary oils on gene expression in goat mammary tissue.

This study investigated the effects of a mixture of steam-flaked corn and extruded soybeans on performance, ruminal development, ruminal fermentation variables, and intestinal absorptive capability in Holstein male calves (n = 39). Calves were assigned to 1 of 3 treatments (13 calves per treatment): 1) milk replacer (MR), 2) one-half of the amount of MR in treatment 1, plus a mixture of 62.1% steam-flaked corn and 30.5% extruded soybeans provided ad libitum (HMCS), or 3) a mixture of 62.1% steam-flaked corn and 30.5% extruded soybeans provided ad libitum (CS). All the calves were started at 2 ± 1 d of age and studied for 150 d. Each 30 d was defined as 1 period. Dry matter intake and growth were measured daily and monthly, respectively. All calves were harvested at 150 d of age, after which rumen fluid was collected. Rumen and intestine samples were gathered. Calves fed MR exhibited greater BW (P = 0.001) and ADG (P < 0.001), compared with calves fed HMCS and CS from period 2 to 3; however, from period 4 to 5, CS calves had greater (P < 0.04) ADG than MR calves. The treatments did not differ in final BW (P = 0.72) and ADG (P = 0.20) from period 2 to 5. Compared with HMCS and MR calves, CS calves had the greatest DMI (P < 0.001) and the least feed efficiency (P < 0.001) from period 2 to 5. For ruminal fermentation parameters, CS calves had decreased (P = 0.04) rumen pH than MR calves. The NH3 concentrations were greater (P = 0.03) in calves fed HMCS than calves fed MR and CS. Total VFA concentrations were greatest in CS calves (P = 0.02). Calves fed CS had the greatest molar concentrations of propionate, butyrate, and valerate (P < 0.002), and calves fed HMCS had the greatest molar concentrations of isobutyrate (P = 0.001) and isovalerate (P = 0.001). The CS calves exhibited greater empty rumen weight (P = 0.001), papillae length (P < 0.001), papillae width (P < 0.001), rumen wall thickness (P = 0.012), and papillae density (P = 0.003). The greatest villus heights in the jejunum (P = 0.04) and ileum (P = 0.005) were observed in CS calves. Compared with HMCS calves, calves fed CS had greater villus:crypt ratios in the duodenum (P = 0.001) and jejunum (P = 0.001). Results indicate that CS improves ADG in period 4 to 5 and positively contributes to ruminal development, ruminal fermentation, and intestinal absorptive capability in veal calves.