Replacement with the cheaper animal fats or vegetable oils is conventional in milk through direct incorporation or homogenization of skimmed milk with less expensive foreign fats. The main objective of the present study was to evaluate the capability of a simple, fast, and reliable method for the detection of added palm oil in butter. The butter samples were mixed with palm oil (0.5-50 wt%) fol...

Mammalian milk fat concentration and composition are variable and responsive to nutritional factors. First described over one and a half centuries ago, diet-induced milk fat depression (MFD) is characterized by a decrease in milk fat yield of up to 50% with no change in milk yield or yield of other milk components. MFD is classically observed in ruminants fed highly fermentable diets or diets t...

The objectives were to determine the effect of dietary fish oil (FO) on uterine secretion of PGF2alpha, milk production, milk composition, and metabolic status during the periparturient period. Holstein cows were assigned randomly to diets containing FO (n = 13) or olive oil (OO, n = 13). Cows were fed prepartum and postpartum diets that provided approximately 200 g/d from 21 d before the expec...

This study examined the effects of supplementation of fish oil and canola oil in the diet on milk yield, milk components and fatty acid composition of Holstein dairy cows in early lactation. Eight multiparous early lactation Holstein cows (42±12 DIM, 40±6 kg daily milk yield) were fed a total mixed ration supplemented with either 0% oil (Control), 2% fish oil (FO), 1% canola oil +1% fish oil (F...

I. Changing cows from a diet with low hay and high flaked maize content, which depressed milk fat secretion, to a high-roughage diet resulted in increased milk fat secretion and in changes in the pattern of rumen fermentation and in the composition of the blood plasma. 2. During the 1st week following the change in diet the proportions of propionic and valeric acids in the rumen decreased and t...

Citrate is a normal constituent of milk that affects milk-processing characteristics. It is an intermediate in the tricarboxylic acid cycle and plays an indirect role in fat synthesis by providing reducing equivalents in the form of NADPH. The objective of this study was to investigate variation in citrate with stage of lactation and de novo fatty acid synthesis, without confounding dietary eff...

Studies concerning associations between candidate gene polymorphisms and milk production traits in cattle are carried out on a large scale (CITEK et al. 2007, KULIG 2005). Stearoyl-CoA desaturase (SCD) is the enzyme involved in conversion of saturated fatty acids into monounsaturated fatty acids. The gene encoding SCD was mapped to bovine chromosome 26 (CAMPBELL et al. 2001), where some QTLs fo...

The interaction of substrates and hormones in response to ingestion of intact proteins during endurance exercise is unknown. This study characterized substrate and hormone responses to supplementation during endurance exercise. Nine male runners participated in 3 trials in which a non-fat (MILK), carbohydrate (CHO), or placebo (PLA) drink was consumed during a 2-hour treadmill run at 65% VO2max...