Effects of postpartum dietary fat and body condition score at parturition on plasma, adipose tissue, and milk fatty acid composition of lactating beef cows1

Abstract

Two experiments were conducted with lactating Angus x Gelbvieh beef cows to determine the effects of postpartum lipid supplementation, BCS at parturition, and day of lactation on fatty acid profiles in plasma, adipose tissue, and milk. In Exp. 1, 36 pri-miparous cows (488 +/- 10 kg of initial BW; 5.5 +/- 0.02 initial BCS) were given ad libitum access to hay and assigned randomly to a low-fat (control) supplement or supplements with cracked, high-linoleate safflower seeds (linoleate) or cracked, high-oleate safflower seeds (oleate) from d 3 to 90 of lactation. Diets were formulated to be isonitrogenous and isocaloric; safflower seed diets provided 5% of DMI as fat. Plasma and milk samples were collected on d 30, 60, and 90 of lactation. Adipose tissue biopsies were collected near the tail-head region of cows on d 45 and 90 of lactation. In Exp. 2, 3-yr-old cows achieving a BCS of 4 +/- 0.07 (479 +/- 36 kg of BW) or 6 +/- 0.07 (580 +/- 53 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr). Beginning 3 d postpartum through d 61 of lactation, cows were fed diets similar to those of Exp. 1. Adipose tissue and milk samples were collected on d 30 and 60, and plasma was collected on d 31 and 61 of lactation. Responses to postpartum dietary treatment were comparable in both experiments. Cows fed linoleate and oleate had greater (P < 0.001) total fatty acid concentrations in plasma than cows fed control. Except for 15:1, milk fatty acids with <18 carbons were greatest (P < or = 0.01) for cows fed control, whereas milk from cows fed linoleate had the greatest (P < or = 0.02) 18:1trans-11, 18:2n-6, and cis-9, trans-11 CLA. Milk from cows fed oleate had the greatest (P < 0.001) 18:1cis-9. In Exp. 1, total fatty acid concentrations in adipose tissue samples decreased at d 90 compared with d 45 of lactation, but the fatty acid profile of cow adipose tissue was not affected (P = 0.14 to 0.80) by dietary treatment. In Exp. 2, the percentage of cis-9, trans-11 CLA in adipose tissue of cows with a BCS of 6 decreased (P = 0.001) from d 30 to 60 of lactation. Plasma and milk fatty acid composition reflected alterations in postpartum diet. Less medium-chain fatty acids and more 18-carbon fatty acids in milk were indicative of reduced de novo fatty acid synthesis in the mammary gland of beef cows fed lipid supplements; however, the metabolic demands of lactation prevented the deposition of exogenously derived fatty acids in adipose tissue through d 90 of lactation.

Effect of Changes in Body Weight, Body Condition and Back Fat During Last Month of Pregnancy on the Reproductive Efficiency of Bos indicus Cows in the Tropics of Costa Rica

“…Similar conclusions were reached in later studies [21,22]. However recent work [23] found that postpartum supplemental fat and not BCS at calving affected plasma and adipose tissue fatty acid profiles of suckling beef cows. Moreover, Chavez et al [24] in agreement with the present study, found a poor relationship between BCS and the energy reserves of the animal expressed currently as body fat (BF).…”

Vaccenic Acid and cis‐9,trans‐11 CLA in the Rumen and Different Tissues of Pasture‐ and Concentrate‐Fed Beef Cattle

“…It is known that pasture feeding resulted in significantly higher concentrations of cis-9,trans-11 CLA in milk and intramuscular fat [1,13,20,34,35]. With pasture feeding, the duodenal flow of VA is higher, compared with low forage-containing diets, in which lipids are higher in linoleic acid [33,36,37]. Furthermore, Piperova et al [33] and Sackmann et al [37] demonstrated that the duodenal output of trans 18:1 fatty acids was high in trans-10 18:1 in diets with low forage contents.…”

“…Furthermore, Piperova et al [33] and Sackmann et al [37] demonstrated that the duodenal output of trans 18:1 fatty acids was high in trans-10 18:1 in diets with low forage contents. Under these conditions, shifts in the ruminal biohydrogenation pathway have occurred resulting in trans-10 18:1 replacing VA as predominant trans 18:1 fatty acids isomer leaving the rumen [33,36,38]. Finally, the amount of duodenal trans-10,cis-12 CLA isomer was significantly increased in cows fed diets with a low forage content [33].…”

“…For blood lipids, phospholipids and cholesterol esters are the main components and account for over 95% of the total lipids in the plasma of ruminant animals. However, triglycerides and free fatty acids only represent \ 5% and 1% of total plasma lipids, respectively [36]. PUFA that escape ruminal biohydrogenation are preferentially esterified to the plasma cholesterol esters and phospholipids [39].…”

Nutritionally Desirable Fatty Acids Including Cla of Cow's Milk Fat Explained by Animal and Feed Factors

“…Performance probably also affects differences caused by parity. Lake et al (2007) a, b, c, d = means in breed and parity groups with different superscripts within a row differ at P < 0.05, in feeding ration groups at P < 0.01, CF = Czech Fleckvieh, H = Holstein, III, VI, IX, XII = feeding rations in March, June, September, and December -see Tab. II, SEM = standard error of the mean, RSD = relative standard deviation (%) = [standard deviation / mean].100; 1 C4-14 = saturated FA, even, MUFA = monounsaturated FA, cis isomers, BCFA = branched chain FA, PUFA n-6 = polyunsaturated FA n-6, PUFA n-3 = polyunsaturated FA n-3.…”