Addition of protected and unprotected fish oil to diets for dairy cows. I. Effects on the yield, composition and taste of milk

Abstract

Thirty Holstein cows in mid-lactation (158±20 DIM) were given a total mixed ration based on grass silage, maize silage and rolled barley. After a preliminary period of 1 week, this diet was supplemented with nothing (control), unprotected fish oil (3.7% of dry matter, DM), or two levels of glutaraldehyde-protected microcapsules of fish oil (1.5% and 3.0% of DM, respectively). Unprotected and protected supplements contained, respectively, 74% and 58% of DM as lipids. Cows given the unprotected supplement reduced their feed intake by >25%. Consequently, these cows lost body weight and produced less milk. DM intake, body weight, and milk yield were unaffected by protected fish oil. Fish oil reduced both milk fat and protein percentages, and decreased the proportion of short-chain fatty acids, stearic, and oleic acids in milk fat. Milk trans C18[ratio ]1 fatty acids increased in cows given both unprotected and protected fish oil. Milk fat content of very-long-chain n3 polyunsaturated fatty acids, including C20[ratio ]5 and C22[ratio ]6, increased with fish oil in the diet. Accordingly, the peroxide index increased and a taste panel was able to detect unusual taste in milk from cows consuming the higher level of protected fish oil and disliked the milk from cows given unprotected fish oil. In conclusion, when lactating cows consumed fish oil, milk concentration of long-chain n3 fatty acids increased and mammary de novo synthesis of fatty acids decreased, but milk yield and milk protein content were reduced, and the milk was more susceptible to oxidation and its taste was adversely affected.

Dietary influence on a desirable fatty acid composition in milk from dairy cattle

“…With antioxidants, different in the water and lipid solubility supplied into the feed (into the rumen or the abomasum as into the milk) the milk flavour decreased quickly with the time after milking. Comparable results have been presented by Lacasse et al (1998).…”

Conjugated linoleic acids in milk fat: Variation and physiological effects

“…The milk was produced by feeding cows with supplementary soybean oil and fish oil. Lacasse, Kennelly, Delbecchi, and Ahnadi (2002), in contrast, reported that a taste panel easily detected deterioration of pasteurized and homogenized milk from cows fed protected (3%) and unprotected (3.7%) fish oil. However, the supplementation of fish oil in their study was rather high compared with other studies.…”

Improving the Quality of Milk Fatty Acid in Dairy Cows Supplemented with Soybean Oil and DHA-Micro Algae in a Confined Production System

“…Supplementation with DHA and EPA from fish oil did not affect rumen environment nor fiber digestion [11] but may affect the palatability of the animal ration as well as the taste, smell and rancidity of the final dairy products [12]. This can be prevented by using other organisms of marine origin such as algae and plankton that are rich in EPA and DHA [13] and also heterotrophic microalgae such as Schizochytrium limacinum (All-G-Rich, Alltech Inc.).…”