Inclusion of fresh forage in the ration for dairy cows: effects on CLA and trans C18:1 isomers content of milk fat

Milk fat is the richest natural source of conjugated linoleic acid (CLA) isomers. The 9-cis, 11-trans CLA isomer (rumenic acid, RA) origins from two pathways: as an intermediate of the rumen biohydrogenation process of linoleic acid or as the product of the activity of mammary Stearoyl Co-A desaturase enzyme (SCD) with trans-11, C18:1 (vaccenic acid, VA) as the precursor, another intermediate in the biohydrogenation of linoleic and linolenic acid

Effect of forage/concentrate ratio and soybean oil supplementation on milk yield and quality from dairy goats

Dietary energy level is a limiting factor of milk production mainly in early lactation goats. Energy intake may be increased by incorporation of fat in ration. Currently, rumen protected fat is mainly adopted in goats nutrition, since the several studies have clearly confirmed that supplies of protected fat markedly improved the fat percentage of goat milk (Schmidely and Sauvant, 2001; Chilliard et al., 2003)

Comparison of fatty acid profile in lamb meat and baby food based on lamb meat

The aim of this study was to compare the fatty acid (FA) profile of fresh lamb meat with those of baby foods based on lamb meat. For this purpose, samples of commercial homogenized (HO) and lyophilized (LIO) baby food based on lamb meat and fresh lamb meat (FM) were analyzed for their FA composition. All fatty acids, except for oleic acid and conjugated linoleic acid (CLA), differed among the three baby products tested. The sum of omega-6 FA and the ratio omega 6/omega 3 FA were lower in FM and LIO meat compared to HO samples. The content of total PUFA n-3 was the highest in FM, because of its highest content of C18:3 n3, EPA, DPA and DHA compared to LIO and HO baby food. The content of arachidonic acid was more than 6-fold higher in FM compared to LIO and HO. This study evidenced the possibility of enhancing the FA profile of commercial baby food based on lamb meat by using meat with healthier FA profile

Transcriptomic analysis of two sheep breeds during lactation, using a new custom microarray platform

Individual milk samples were weekly collected from 48 ewes during eight weeks. Ewes were at the second month of lactation and they were fed the same dietary regimen. The animals were grouped according to the amount of daily milk fat yield: A) 38-57g/d, B) 58-63g/d, C) 64-73g/d, D) 75-110g/d. Milk from group D showed a higher content of FA from C4 to C10 and a lower content of monounsaturated FA (MUFA) and conjugated linoleic acids (CLA) than Group A (+12%, -11%, and -18%, for C4 to C10, MUFA and CLA, respectively), while Group B and C showed intermediate values. CLA content increased with days of lactation in a similar way for all groups. The mean correlation among all records within each individual lactation was 0.45 for CLA content. Six milk FA pair ratios representing a proxy for SCD activity were also evaluated: group A showed higher values of FA ratios than Group D (+26% on average for all FA pairs). In conclusion, increasing ability of daily milk fat yield was associated with lower milk content of MUFA and CLA and higher content of FA from C4 to C10

Whole extruded linseed in the diet of dairy ewes during early lactation: effect on the fatty acid composition of milk and cheese

In a long term supplementation trial (10 weeks), the effects of the inclusion of whole extruded linseed in the diet of dairy ewes on milk and cheese fatty acid composition were evaluated. Two groups of 24 Sarda ewes in early lactation were randomly assigned to control concentrate (800 g/d concentrate, C) or whole extruded linseed concentrate (L, 700 g/d, with 30% of extruded linseed, Omega-Lin®). Results showed that, after 2 weeks on the L diet, the milk content of unsaturated fatty acid (UFA), including rumenic acid (RA), vaccenic acid (VA) and alfa-linolenic acid (ALA) increased sharply compared to C group, reaching the highest levels after 7-8 weeks (3.06, 7.31 and 2.31 g/100 g milk fat for RA, VA and ALA, respectively). During the last 2 weeks of the experimental period, when pasture was included in the diet of both groups, the content of the above fatty acids slightly decreased in milk from L group, whereas in milk from C group increased. Nevertheless, the average content of these fatty acids in milk from L group remained significantly higher than that of milk from C group. Compared with the control, the L diet resulted in a significant reduction (-17%) in the concentration of saturated fatty acid in milk. The fatty acid content of the cheese obtained from milk of the two groups reflected the milk fatty acid composition. The inclusion of extruded linseed in the diet of dairy ewes improved the nutraceutical properties of milk and cheese, but further researches are needed in order to better understand the relationship between basal diet and lipid supplementation in dairy ewes

Olive oil calcium soaps and rumen protected methionine in the diet of lactating ewes: effect on milk quality

Eight Massese ewes were fed 4 diets with alfalfa hay as the forage (73% on the DM basis): 1) control diet (C); 2) diet C supplemented with olive oil calcium soaps, 50 g/d (L); 3) diet C supplemented with protected methionine, 5 g/d (M) or 4) plus both soaps and methionine (ML); the experimenthal design was a 4x4 Latin square with 2 replicates per diet. During the experimental periods, lasting one week each, the ewes were milked twice daily (8:00 a.m. and 7:00 p.m.). Milk yield was not affected by diet quality, but milk fat percentage and 6.5% fat corrected milk yield were higher in diets L, M and ML with respect to diet C (P<0.05). Milk protein content was depressed and blood urea increased following the Ca soap diet alone or with protected methionine. Diet M worsened (P lesser than 0.05) Rennet clotting time (r) and curd firmness after 30 minutes (A30). Saturated fatty acids C10:0, C12:0, C14:0 and C16:0 were depressed in milk fat with the Ca soap supple- mented diet, some of them significantly. C18:1 increased (P lesser than 0.05) with diet L only, whereas the association of Ca salts and methionine in diet ML significantly affected the linoleic acid and CLA content. It is concluded that the use of olive oil fatty acids as a protected fat source seems to improve the milk fatty acid char- acteristics towards a safer pattern, but the presence of this type of Ca salts in the diet appears to worsen the metabol- ic utilisation of amino acids