The Effect of Body Energy Reserve Mobilization on the Fatty Acid Profile of Milk in High-yielding Cows

Abstract

We investigated the effect of the amount of body condition loss in the dry period and early lactation in 42 high-yielding Holstein-Friesian cows on milk yield and the share of fatty acids in milk fat. Energy reserves were estimated based on the body condition scoring (BCS) and backfat thickness (BFT). Milk yield and milk composition were determined over 305-d lactation. From d 6 to 60 of lactation, the concentrations of 43 fatty acids in milk fat were determined by gas chromatography. Cows were categorized based on body condition loss from the beginning of the dry period to the lowest point of the BCS curve in early lactation into three groups: low condition loss group (L) ≤0.5 points (n = 14); moderate condition loss group (M) 0.75 to 1.0 points (n = 16) and high condition loss group (H) >1.0 points (n = 12). Cows whose body energy reserves were mobilized at 0.8 BCS and 11 mm BFT, produced 12,987 kg ECM over 305-d lactation, i.e. 1,429 kg ECM more than cows whose BCS and BFT decreased by 0.3 and 5 mm, respectively. In group H, milk yield reached 12,818 kg ECM at body fat reserve mobilization of 1.3 BCS and 17 mm BFT. High mobilization of body fat reserves led to a significant (approx. 5%) increase in the concentrations of monounsaturated fatty acids-MUFA (mostly C18:1 cis-9, followed by C18:1 trans-11), a significant decrease in the levels of fatty acids adversely affecting human health, and a drop in the content of linoleic acid, arachidonic acid and docosahexaenoic acid in milk fat. In successive weeks of lactation, an improved energy balance contributed to a decrease in the concentrations of unsaturated fatty acids (UFA) and an increase in the conjugated linoleic acid (CLA) content of milk fat.

Dry period plane of energy: Effects on feed intake, energy balance, milk production, and composition in transition dairy cows

“…Differences in C18:0 between cows being fed different planes of energy during the dry period were also observed by Agenäs et al (2003), and the authors hypothesized them to be due to a higher supply of FA from body origin. The FA cis-9 C18:1 is the desaturation product of C18:0 through the action of ∆(9)-desaturase, and is the predominating FA in adipocytes (Nogalski et al, 2012). It is released during negative energy balance through lipolysis (Rukkwamsuk et al, 2000).…”

Fatty acid composition of buffalo and bovine milk as affected by roughage source - silage versus hay

“…Parity has been found to explain part of the variation in FA profile of milk in bovine and bubaline cows (Samková et al, 2012;Nogalski et al, 2012a;Qureshi et al, 2012). However, here the greater RSME values at TD1 suggest that this part is not big and the variation due to lactation stage is obviously more substantial at this phase of the experiment, while after one more month (TD2) it is diminished.…”

“…The effect of lactation stage on fatty acid composition of milk is mainly linked to body fat mobilization in early lactation (Nogalski et al, 2012b;Stoop et al, 2009). If we can rely on the three months of the present experiment and on the within-group differences among test days, the milk FA's from the bovine cows fed silage and hay show different patterns of alteration.…”

The Effect of Slaughter Weight and Fattening Intensity on Changes in Carcass Fatness in Young Holstein-Friesian Bulls

“…However, the cited authors analysed beef breeds which differ considerably from dairy breeds, including Holstein-Friesians, with respect to, among others, the rate of muscle and fat deposition. Dairy cows, in particular Holstein-Friesians, accumulate fat reserves that can be used as an additional energy source at the beginning of lactation when their nutrient requirements exceed feed intake (Nogalski et al, 2012). It is the result of many years of cow selection, which to some extent may affect the accumulation of fat in bulls of the breed (Pfuhl et al, 2007).…”