Milk Fatty-Acid Profile after Feeding Increasing Doses of a Mixture of Soybean and Linseed Oils to Pasture Dairy Cows

• 作者: Gerardo Antonio Gagliostro Liliana Elisabet Antonacci
• 来源期刊: 动物研究(英文)
• 学科: 经济
• 关键词: Polyunsaturated oils Vegetable oils Rumenic acid
• 年，卷（期）: 2019,（3）
• 页码范围: 8-22
• 页数: 15页
• 分类号: F42

摘要

The goal was to determine the effect of growing intake of a mixture(75:25)of soybean(SoOi)and linseed(LiOi)oils on milk production and composition and milk fatty-acid(MF-A)profile in grazing dairy cows.Twenty-four Holstein cows were assigned to 4 treatments in a completely randomized design with three weeks of adaptation to oil doses and one week of experimental measurements.On a dry matter(DM)basis,cows were fed pasture(63%),energy concentrate(37%)and the SoOi LiOi oil mixture at zero(Tr0%),2%(Tr2%),4%(Tr4%)and 6%(Tr6%)of total DM intake equivalent to 0,0.36,0.72 and 1.08 kg/cow/day of the oil mixture.The oil mixture was manually mixed-up to the concentrate(7.04 kg DM/cow/day)and supplied by halves during each milking time without refusals.Pasture(P=0.49)and total DM intakes(P=0.31)were similar between treatments averaging 11.27 and 18.85 kg DM/cow/day respectively.Milk output(22.71 kg/cow/day)was not affected(P=0.46).Milk fat content reduced linearly(P<0.05)from 3.20(Tr0%)to 2.67 g/100g(Tr6%)without effects(P=0.73)on fat or fat corrected milk(4%FCM)yields.Milk protein concentration(P<0.56)or yields(P<0.11)were not affected.Lactose contents tended(P<0.08)to be higher in oil supplemented cows and milk urea nitrogen was not affected(P=0.14).The basal(Tr0%)concentration(g/100g MF-A)of totaly hypercholesterolemic MF-A(C12:0,C14:0 and C16:0)averaged 38.93 and decreased linearly(P<0.0001)with oil intake to 37.81(Tr2%),31.59(Tr4%)and 29.18(Tr6%).Levels of elaidic(trans-9 C18:1)and trans-10 C18:1 MF-A resulted low-slung in the basal(Tr0%)milk(0.21 and 0.20 g/100g MF-A,respectively)but increased linearly(P<0.0001)after oil intake reaching the maximum values at Tr6%(0.73 and 2.23 g/100g MF-A,respectively).Milk concentration(g/100g MF-A)of vaccenic acid(trans-11 C18:1,VA)averaged 3.63 in Tr0%and increased linearly(P<0.0001)with oil intake reaching 4.97,7.05 and 8.38 in Tr2%,Tr4%and Tr6%,respectively.Basal concentration of rumenic acid(cis-9.trans-11 C18:2,RA)was 2.28 g/100g MF-A and increased linearly(P<0.0001)with increas