Effect of unsaturated fatty acid supplementation on performance and milk fatty acid profile in dairy cows fed a high fibre diet

Abstract

The influence of unsaturated fatty acid (UFA) supplement on productive performance, physiochemical properties and fatty acid (FA) profile of milk, was investigated in lactating dairy cows fed with high fibre diets. According to a cross-over design, twelve cows were assigned to two experimental settings characterized by different FA profiles. Cows received a high fibre diet (~42% NDF on DM basis) supplemented with soybean based mixtures with these FA compositions: 92.0% of saturated FA (SFA), 2.8% of monounsaturated FA (MUFA) and 5.2% of polyunsaturated FA (PUFA) in the control diet (C-diet); 19.1% of SFA, 20.9% of MUFA and 60.0% of PUFA in the experimental diet (E-diet). The E-diet did not affect dry matter intake nor milk yield. Milk composition and coagulation traits resulted similar between treatments, except for the lactose level, which was lower in the E-diet (5.0 vs 4.8%; P<0.05) and the freezing point (-0.546 vs -0.535 °C; P<0.05). As respects the milk FA profile, the E-diet significantly increased the percentage of UFA because of their greater amount in the ration; however the "transfer" of UFA in milk was limited by the high level of FA biohydrogenation (BH) at the ruminal level. UFA showed low values of carry over in milk (67.5 vs 39.7%; P<0.001) due to the saturation process; on the contrary SFA had a threefold increment (124 vs 323%; P<0.001), mostly due to a peak in the production of stearic acid. In this study, the percentage of CLA in milk (0.50 vs 0.62%; P<0.05) was quite low for both diets, if compared with other studies, and this was probably due to a low vaccenic acid supply at duodenal level. E-diet (5,00 vs 4,81%; P<0,05), e del punto crioscopico (-0,546 vs -0,535 °C; P<0,05

Treatment and post-treatment effects of dietary supplementation with safflower oil and linseed oil on milk components and blood metabolites of Canadian Holstein cows

“…Our data are supported by Chichlowski et al (2005) who reported significantly lower concentrations of MUN and reduced (not significant) blood urea nitrogen concentrations of cows fed ground canola seeds as compared to control. Our data, however, contrast observations by several authors who found no significant effects of diets rich in UFA on MUN levels in Italian (Marchesini et al 2009) and Brown Swiss cows (Sigl et al 2010). In one of the studies, a high fibre diet was used suggesting that the composition of the diet is an important factor (Marchesini et al 2009).…”

“…Our data, however, contrast observations by several authors who found no significant effects of diets rich in UFA on MUN levels in Italian (Marchesini et al 2009) and Brown Swiss cows (Sigl et al 2010). In one of the studies, a high fibre diet was used suggesting that the composition of the diet is an important factor (Marchesini et al 2009). The concentration of urea in milk is monitored in many dairy herds as an indicator of the efficiency of protein utilization (Rafieei 2011), as well as nitrogen elimination to the environment.…”

Multivariate Modelling of Milk Fatty Acid Profile to Discriminate the Forages in Dairy Cows' Ration

“…As reported by Riuzzi, et al 25 , a lower lactose content was found in milk from GRG cows probably because of both their lowest recorded intake and the lower level of energetic concentrates, potentially leading to less ruminal propionate synthesis compared with other groups. Since proprionate is the main precursor of gluconeogenesis in ruminants, this can lead to a decrease in glucose and hence lactose 34 .…”

Effect of season and herd on rennet coagulation time and other parameters of milk technological quality in Holstein dairy cows

“…However, also those authors who did not primarily study problems of technological quality of milk concluded that the coagulation properties of milk (i.e. its rennetability) should be involved among eff ects analysed in experiments with dairy cows (Marchesini et al, 2009;Masoero et al, 2009).…”