Lipid Metabolism in Adipose Tissue of Cows Fed High Fat Diets During Lactation

Abstract

The adaptations of fat synthesis in adipose tissue to lactational state, rate of milk production, and dietary fat intake were determined for dairy cows. Lipogenesis and esterification were determined in cows of average or high genetic merit for milk production and fed either a control TMR of corn silage, alfalfa, and concentrate (2.5% fat; 1.47 Mcal of NEL/kg); a TMR with whole cottonseeds replacing 12% of the concentrate (4.4% fat; 1.49 Mcal NEL/kg); or a TMR with 12% cottonseeds and 2.7% of Ca salts of fatty acids (6.0% fat; 1.53 Mcal of NEL/kg). Dietary treatments began on d 17 of lactation and continued for 288 d. Lipogenesis and esterification decreased equally from 15 d prepartum to 15 d postpartum in all groups. Cows of high merit had lower rates of lipogenesis and esterification at d 60 than did low merit cows but had higher rates of lipogenesis at d 120. Rates of lipogenesis were decreased by dietary fat treatments. Esterification rates were lowest on the intermediate fat TMR and highest on the highest fat TMR. Lipogenesis was decreased logarithmically by dietary fat intake; this effect was greater as lactation progressed. Adipocyte size and body fat mass decreased during early lactation and then increased for all treatment groups. Supplemental dietary fat reduces de novo synthesis of fatty acid, and this effect increases as lactation progresses.

Quantification of pericaudal adipocyte diameter in dairy cattle during peripartum: a complementary method to study energetic status using conventional histology

“…The BCS is a widespread indirect measure of fat storage in dairy cows (Edmonson et al., 1989), sometimes used associated with the measurement of adipocytes from subcutaneous adipose tissue biopsies (Smith and McNamara, 1990; Waltner et al., 1994), with fat depth measured by ultrasonography (Garnsworthy and Topps, 1982) or with body weight (McNamara et al., 1995). In our experimental conditions, the observed variation in BCS, GLY and BHBA agrees with expected normal values for dairy cows during peripartum (Chilliard, 1999; Dann et al., 2005; Hachenberg et al., 2007).…”

“…In dairy farms, seric concentrations of calcium, non‐esterified fatty acids and ß–hydroxybutyrate (among other metabolites like glucose) during peripartum were frequently used associated with BCS to evaluate adaptation to NEB (McNamara et al., 1995; Rukkwamsuk et al., 1998, Kokkonen et al., 2005). As a result of NEB adaptation, significant lipid mobilization from subcutaneous adipose tissue leads to a progressive loss of body mass that decreases BCS (Chilliard, 1999).…”

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

“…The aim now is to develop new feeding strategies for lactating ruminants (Table 2) in which an independent regulation of the different C 181 has been considered. Possible ways to meet this goal include pasture feeding (Dhiman et al, 1999), concentrate to roughage management (Jiang et al, 1996;Griinari et al, 1998), and the use of protected plant oils and the use of milk fat insensitive cows (McNamara et al, 1995;Kelly et al, 1998). From the literature we conclude that the supply of canola oil compared to soya or linseed oil in the ration increases CLA in milk relatively more than trans fatty acids (Table 3).…”

The influence of dietary rumen-protected linoleic acid on milk fat composition, spreadability of butter and energy balance in dairy cows

“…This is partly due to an increased energy intake, a more efficient ATP formation than that caused by short-chain FAs, direct incorporation into milk fat as well as to an homeorhetic beneficial effect of the fat on the mammary gland as compared with propionic acid or glucose derived from starch [6]. Fat-supplemented rations that are high in polyunsaturated FAs (PUFA) have been shown to be related to high contents of trans FAs (TFA) in the milk fat.…”