Milk fatty acid composition and conjugated linoleic acid content of Jersey and Fleckvieh x Jersey cows in a pasture-based feeding system

Abstract

A number of fatty acids (FAs), such as omega-3, omega-6 and conjugated linoleic acid (CLA), which are present in the milk from dairy cows are considered essential FAs and beneficial nutrients for humans. The aim of the study was to compare the milk FA content, particularly the CLA, omega-3 and omega-6 FA content of the milk fat of Jersey and Fleckvieh x Jersey (F x J) cows in a pasture-based feeding system. All cows were fed the same diet consisting of kikuyu-ryegrass pasture in a rotational grazing system supplemented with a standard commercial concentrate mixture at 7 kg per cow per day. Five milk samples were collected every five weeks from 10 days after calving, that is, days in milk (DIM) up to 175 DIM. In addition, two samples were collected every five weeks from 240 DIM to the end of the lactation period. Sampling was done at the evening and following morning's milking session and pooled for each cow. Samples were kept frozen at −20 ºC until laboratory analysis by gas chromatography. Thirty six FAs were detected and concentration levels determined. Higher levels of total CLA (0.74 ± 0.02 vs. 0.63 ± 0.02 g FA/100 g fat), linoleic acid (1.51 ± 0.03 vs. 1.36 ± 0.04 g FA/100 g fat) and total omega-6 FAs (1.74 ± 0.04 vs. 1.54 ± 0.05 g FA/100 g fat) were recorded in the milk fat of F x J cows in comparison with Jersey cows, respectively. Increases in total CLA and the c9,t11 CLA isomers in the milk of Jersey and F x J cows followed the same trend, showing an increase from the beginning to the end of the lactation period. Similarly, the CLA content of the milk fat showed an increase with lactation stage for both breeds. ______________________________________________________________________________________

Seasonal variation of fatty acids composition of milk from grazing ewes in Thessaly, central Greece

“…Feeding lactating ewes with pasture or lipid supplements rich in PUFA results in milk rich in MUFA and PUFA (Mierlita et al, 2011). In accordance with the present results, similar seasonal effect with a decrease in SFA, and an increase in MUFA and PUFA of the milk produced by lactating ewes (Atti et al, 2006;Meluchova et al, 2008;Abilleira et al, 2009;Carloni et al, 2010), cows (Sasanti et al, 2015) or goats (Sampelayo et al, 2007), under grazing pasture feeding conditions, were observed in previous studies.…”

“…Papaloukas et al, (2016) reported that bulk ovine milk produced by various sheep breeds fed on grazing pasture in mountainous areas in Northern Greece showed cis-9, trans-11 CLA values of 0.58, 0.98 and 1.12% FAME in winter, spring and summer, respectively. Seasonal variations of C18:2 cis-9, trans-11 CLA in milk from cows (Chion et al, 2010;Sasanti et al, 2015) or goats (Milewski et al, 2018) produced under grazing pasture feeding conditions were also reported. Signorelli et al, (2008) examined the FAs composition of ovine milk produced by lactated ewes under the same combined pasture and concentrate feeding conditions and found cis-9, trans-11 CLA levels of 1.905%, 1.958% and 1.617% FAME for the Italian breeds, Altamurana, Gentile di Puglia and Sarda, respectively.…”

Effect of alternating total mixed ration and pasture feeding on the fatty acid content and health indices of Jersey and Fleckvieh x Jersey milk

“…The effects of diet and breed on FA content are shown in Table 1. In contrast with an earlier study which showed that breed and lactation stage affected the content in milk fat and some FAs (Sasanti et al, 2015), the present study showed that the FA content of the milk of cows was not affected by breed (P >0.05) except for C8:0 (P <0.008) and C12:0 (P <0.026). There was no (P >0.05) lactation stage effect, although a linear trend was observed for most FAs, however, with no significant difference between means.…”

“…Interestingly, the increase in CLA and C18:3n-3, when cows were put back on pasture (Pasture 2) was higher (P <0.05) than the initial levels on pasture (Pasture 1). This higher content is probably related to lactation stage, although was not significant between means, similar to a study by Sasanti et al (2015) which showed that while CLA levels differed between breeds, higher levels were shown towards the end of the lactation period.…”

“…Grega et al (2005) and Hennessy et al (2007) found that Simmental-derived breeds such as the Fleckvieh (F) from Germany have higher milk CLA levels than other breeds on similar feeding programmes. Sasanti et al (2015) also showed breed differences between Jersey (J) and FxJ cows with regard to milk yield, milk composition and the CLA content of the milk fat of cows. The Fleckvieh breed has dual-purpose characteristics, producing beef and high solids milk, and has crossbreeding potential to improve the lifetime performance of dairy cows.…”