Abstract #LB8
Section: Late-Breaking Original Research Abstracts
Session: Late-Breaking Original Research Abstracts
Format: Oral
Day/Time: Sunday 4:45 PM–5:00 PM
Location: Ballroom C
Session: Late-Breaking Original Research Abstracts
Format: Oral
Day/Time: Sunday 4:45 PM–5:00 PM
Location: Ballroom C
# LB8
Dairy cows supplemented with conjugated linoleic acid and α-linolenic acid differ in their 13C enrichment in milk fat and casein after [13C6] glucose infusion during early lactation.
H. M. Hammon*1, L. Vogel1, M. Gnott1, C. Kröger-Koch1, S. Görs1, C. C. Metges1, A. Tröscher2, A. Starke3, 1Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany, 2BASF SE, Lampertheim, Germany, 3Clinic for Ruminants and Swine, Faculty of Veterinary Medicine University of Leipzig, Leipzig, Germany.
Key Words: cow, fatty acid supply, 13C enrichment
Dairy cows supplemented with conjugated linoleic acid and α-linolenic acid differ in their 13C enrichment in milk fat and casein after [13C6] glucose infusion during early lactation.
H. M. Hammon*1, L. Vogel1, M. Gnott1, C. Kröger-Koch1, S. Görs1, C. C. Metges1, A. Tröscher2, A. Starke3, 1Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany, 2BASF SE, Lampertheim, Germany, 3Clinic for Ruminants and Swine, Faculty of Veterinary Medicine University of Leipzig, Leipzig, Germany.
In the present study the hypothesis was tested that the supplementation of conjugated linoleic acid (CLA) and α-linolenic acid of dairy cows may affect milk synthesis by the different utilization of precursor carbon atoms from glucose in the mammary gland. Holstein cows (n = 40) fed a corn silage based diet were fitted with abomasal tubes placed through rumen cannula and were supplemented either with coconut oil (45.5% C12:0, 16.9% C14:0; CNTR, 76 g/d), linseed (53.9% C18:3) and safflower oil (62.0% C18:2) (EFA, 78 and 4 g/d), Lutalin (CLA, c9, t11 and t10, c12, 10 g/d each) or EFA+CLA starting at wk 9 antepartum. At wk 3 postpartum, [13C6] glucose was infused (bolus injection of 5.38 μmol/kg of BW and constant infusion of 7.53 μmol/kg BW per h for 4 h) to measure the glucose rate of appearance (GlucRa) in blood plasma and 13C enrichment in milk fat, casein, and lactose. Blood and milk samples were taken before and 1, 2, 2.5, 3, 3.5, and 4 h (blood) and 2, 4, 6, 8, 10, 24, 36, 48, 60, and 72 h (milk) after the start of infusion. Data were analyzed using the MIXED procedure of SAS with treatment and time as fixed effects. Milk and protein yield did not differ among groups. Milk fat was reduced (P < 0.001) in CLA groups and milk urea was greater (P < 0.05) in EFA than in CLA and EFA+CLA. GlucRa was lower (P < 0.05) in CLA and EFA+CLA than in EFA. The 13C enrichment peaked 4 h (lactose) or 6 h (fat, casein) after start of [13C6] glucose infusion. In milk fat, 13C enrichment was greater (P < 0.05) in CLA and EFA+CLA than in EFA 4 h, and in CLA than in CNTR (P < 0.05) 6 h after start of infusion. In casein, 13C enrichment was lower (P < 0.05) in CLA and EFA+CLA than in EFA and CNTR 4 h and 6 h after start of infusion. The GlucRa indicated a glucose-sparing effect in CLA and EFA+CLA cows due to less milk fat synthesis. Lower 13C enrichment from glucose carbon in casein and the trend for lower milk urea suggest less amino acid degradation and an elevated usage of preformed amino acids for milk protein synthesis in CLA-supplemented cows.
Key Words: cow, fatty acid supply, 13C enrichment
