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Effects of extruded linseed dietary
supplementation on milk yield, milk quality
and lipid metabolism of dairy cows
P. Pezzi1, M. Giammarco1, G. Vignola1, N. Brogna2
1Dipartimento di Scienze degli Alimenti. Università di Teramo, Italy
2Dipartimento di Morfofisiologia Veterinaria e Produzioni Animali. Università di Bologna, Italy
Corresponding author: Paolo Pezzi. Dipartimento di Scienze degli Alimenti. Facoltà di Agraria,
Università di Teramo. Viale Crispi, 212, 64100 Teramo, Italy - Tel. +39 0861 266991 - Fax: +39 0861
266994 - Email: firstname.lastname@example.org
ABSTRACT: Twenty Italian Friesian dairy cows were used in an experimental trial to study the effects of
extruded linseed dietary supplementation on milk production, milk quality and fatty acid (FA) percentages of milk
fat and total plasma lipids and plasma phospholipids. Control cows were fed a corn silage based total mixed ration
(TMR) while treated animals also received 700g/head/d of extruded linseed supplementation. Feed intake was sim-
ilar between groups. Milk yields was tendentially greater for cows fed extruded linseed. Milk urea content (P<0.05)
were reduced by treatment. Results showed a significant increase n-3 FA concentration (particularly alpha linolenic
acid) and a significant reduction of n-6/n-3 FA ratio in milk fat, total plasma lipids and plasma phospholipids
(P<0.001); moreover a reduction trend (P<0.1) of arachidonic acid concentrations was observed in milk fat, total
plasma lipids and plasma phospholipids. At last, treatment enhanced milk fat conjugated linoleic acid (CLA) per-
Key words: Dairy cow, Linseed, N-3 fatty acids, CLA.
INTRODUCTION – Since dietary polyunsaturated fatty acids (PUFA) are perceived to be healthier than sat-
urated fatty acids, there has been a great deal of interest in increasing milk PUFA concentration to respond to con-
sumers’ demands. Among PUFA, particularly appreciate are n-3 and conjugated linoleic acid (CLA). Feeding
oilseeds to lactating dairy cows is one method to change the proportion of unsaturated FA in milk fat, with increas-
es as high as 40% (Kim et al., 1993), although extensive biohydrogenation occurs normally in the rumen (Palmquist
and Jenkins, 1980). In the present study, the effects of extruded linseed dietary supplementation on milk yield, milk
quality and blood lipid metabolites are evaluated.
MATERIAL AND METHODS – The trial was carried out in a Farm of Teramo Province (Italy). Twenty
Holstein Friesian dairy cows housed free stall were used. Animals were milked two times per day and fed total
mixed ration (TMR).At the beginning of the trial they were divided into two homogeneous groups (age, parity, BCS,
calving time, milk yield capacity and milk quality). TMR was composed (D.M. basis) by 29.03% corn silage, 18.56%
alfalfa hay, 9.39% mixed hay, 13.56% corn ground, 13.56% barley ground, 10.67% soybean meal (44% C.P.), 2.7%
minerals and vitamins premix, 2.16% flaked soybean and 0.37% palm oil calcium soap salts. Treated group also
received 700 g/day extruded linseed supplementation mixed in TMR (2.75% of TMR D.M. basis). TMR was deliv-
ered every day at 9:00 h.Trial time was 4 weeks. Feed intake was recorded as group means by difference from daily
TMR delivered and residues. One week before the starting, and two and four weeks later feed samples was taken
immediately after the delivery to the animals. Samples was analysed for dry matter, crude protein, ether extract,
crude ash (Martillotti et al., 1987), NDF (Van Soest, 1967), and fatty acid percentages (Gas Chromatographic sys-
tem Fisons Mega II). Milk yield was recorded at 0, 2 and 4 weeks after the beginning of the trial by sum of quan-
tity of two consecutive milking. At the same times individual milk and blood (from the jugular vein) samples were
collected. Each blood sample, collected at 8:00 using Lithium heparin tube, was immediately centrifuged (3500 g x
10’) and plasma obtained was readily frozen at –20°C. Milk samples were taken at the milking of 06:00 h and were
analysed for fat, protein, and lactose percentage, somatic cell count and urea content (Milkoskan, Foss Electric, DK).
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334ITAL.J.ANIM.SCI. VOL. 6 (SUPPL. 1), 333-335, 2007
Somatic cell count data were converted in a logarithmic scale: Somatic Cell Score (SCS; Ali and Shook, 1980). Milk
fat (Folch et al., 1957), total plasma lipids (Folch et al., 1957), and plasma phospholipids (Solid phase extraction
method) were analysed for fatty acids percentages (Gas Chromatographic system Fisons Mega II). All data were
processed by multivariate analysis of variance MANOVA for repeated measures. The statistical package employed
was the SPSS Version 3.0.
RESULTS AND CONCLUSIONS – Dry matter intake was not affected by dietary treatment in agreement
with results of Gonthier et al. (2005), and averaged 22.76 kg/d (Table 1). Feeds compositions are shown in Table 1.
As expected only ether extract and fatty acid composition was different between two diets; indeed treated group
received 243.5 vs 42.1 g/head/d of alpha linolenic acid.
Table 1. Feed intake and composition of TMR and extruded linseed.
57.51 ± 1.94
13.59 ± 1.53
3.28 ± 0.42
35.03 ± 1.50
57.88 ± 1.43
13.97 ± 1.31
4.39 ± 0.17
35.19 ± 0.94
Dry Matter Intake
Net Energy Lact.
Fatty acids *
C18:3 n-3 (ALA)
19.52 ± 1.49
23.04 ± 0.95
49.16 ± 2.03
5.98 ± 0.69
16.39 ± 0.78
21.68 ± 0.28
34.84 ± 0.53
25.51 ± 0.69
(*) 2.30% and 1.57% respectively in control and treated TMR were undefined peeks.
As shown in Table 2 milk yield was higher (but not significantly) in treated group.This finding is in agreement with
data of Petit et al. (2004). Probably higher energy content of treated diet was the cause of this finding. Interestingly
milk fat percentage was not depressed by n-3 fatty acid supplementation; also this result was in agreement with
Petit et al. (2004). Interestingly milk urea content was higher in control group (P<0.05); this result may be
explained by a better utilization of metabolizable protein to synthesize milk protein in treated group.
Table 2.Milk production and milk quality.
Dietary extruded linseed supplementation significantly increased n-3 fatty acids concentration and particularly
alpha linolenic acid in total plasma lipids (P<0.001), in plasma phospholipids (P<0.001) and in milk fat (P<0.001;
Table 3). Treatment showed also a significant decrease of n-6/n-3 fatty acid ratio (P<0.001) and a tendentially
reduction of arachidonic acid percentage (P<0.1) in milk fat, in total plasma lipids and in plasma phospholipids.
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ITAL.J.ANIM.SCI. VOL. 6 (SUPPL. 1), 333-335, 2007 335
These findings are supported by data from other studies (Petit et al., 2002; Petit et al., 2004).Treated animals show
a significant increase in milk fat CLA content (P<0.01) in agreement with Gonthier et al., (2005).
Table 3. Fatty acid composition of milk fat.
Fatty acidsControl TreatedSEMTreatment Week
CLA cis 9, trans 11
The Authors want to thanks Mignini S.p.A.
The research was supported by “Fondo di Ricerca d’Ateneo (ex 60%) 2005” University of Teramo.
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