Effects on milk quantity and composition associated with extruded linseed supplementation to dairy cow diets

The effect of increasing extruded linseed level on nutrient digestibility, growth, carcass characteristics, and non-carcass components of lambs from two genotypes

This research aimed to study the effect of extruded linseed level on digestibility, growth, carcass, and non-carcass components of two genotypes' lambs. For this, 36 lambs, with an average body weight (BW) of 21.3 ± 3.4 for Queue Fine de l'Ouest (QF) and 17.8 ± 2.9 kg for the cross QF × D'man (QF × D), were randomly divided into three groups of 12 lambs each (six per genotype) in a 12-week experiment. Sheep in each group received individually oat hay ad libitum and one of three concentrates containing 0% (control), 15% (L15), and 30% (L30) of extruded linseed on a dry matter basis. All concentrates were isocaloric and iso-nitrogenic. In the last 2 weeks, digestibility was measured, and then all lambs were slaughtered. The increasing level of extruded linseed did not affect hay and total dry matter (DM) intake as well as nutrient digestibility, except the neutral detergent fiber (NDF) digestibility which was significantly (P < 0.05) reduced by the diet treatment (66.4, 57.8, and 53.0% for C, L15, and L30, respectively). In addition, the different linseed levels resulted in similar average daily gain, final BW, carcass traits, and non-carcass components except the rumen and liver weights which were significantly (P < 0.05) reduced by the increasing linseed level. However, the addition of extruded linseed improved (P < 0.05) the weight of the heart. The carcass tissular composition was not affected by the dietary treatment guarding a similar proportion of muscle, bone, and fat. However, the growth performance and carcass traits were higher for cross QF × D than QF lambs. In addition, the carcasses were leaner (less fat and more muscle) for the cross genotype (P < 0.05) than the pure QF breed. It was concluded that extruded linseed can be used in lamb diet without adverse effects on growth performance and carcass components. Furthermore, the cross could be planned given it resulted in higher growth and better carcass composition.

The pathogenic potential and genetic attributes of Escherichia coli in milk from dairy cows with subclinical mastitis

The centrality of milk and dairy products to the human diet allows potential pathogens to pose a threat to human health. Pathogenic Escherichia coli is a zoonotic foodborne pathogen with many virulence genes which cause variations in its pathogenicity. The current study aimed to investigate the pathogenic potential of E. coli from milk of dairy cows with subclinical mastitis and evaluate the genetic relatedness to E. coli from human sources. The majority of the E. coli isolates belonged to the A (55.0%) and B2 (22.5%) phylogenetic groups and the most prevalent virulence genes were colV (90.0%), fyuA (75.0%) and vat (42.5%). Mice injected with G4-BD23 (P < 0.05) and G5-BD3 had lower survival rates than controls and visible pathological changes to lung and kidney. Nineteen MLST types were identified in 40 dairy E. coli isolates and three STs (ST10, ST48 and ST942) were shared with those from human sources. Some dairy E. coli isolates were phylogenetically related to human E. coli isolates indicating pathogenic potential.

Effect of Flaxseed Supplementation on Milk and Plasma Fatty Acid Composition and Plasma Parameters of Holstein Dairy Cows

The objective of this study was to determine the effect of whole flaxseed and ground flaxseed supplementation on the composition of fatty acids in plasma and milk, particularly the content of omega-3 polyunsaturated fatty acids (n-3 PUFAs). Thirty Holstein dairy cows were randomly assigned to three treatment groups. Cows were fed a total mixed ration without flaxseed (CK), 1500 g of whole flaxseed (WF), and 1500 g of ground flaxseed (GF) supplementation. There were no differences observed in dry matter intake, milk yield, energy-corrected milk, and 4% fat-corrected milk (p > 0.05). Compared with the CK group, the contents of α-linolenic acid (ALA), eicosatrienoic acid, and eicosapentaenoic acid increased in the plasma and milk WF and GF groups, and the content of docosahexaenoic acid and total n-3 PUFA was higher in GF than the other groups (p < 0.001). The ALA yield increased to 232% and 360% in WF and GF, respectively, compared to the CK group. Compared with the WF group, GF supplementation resulted in an increased milk ALA/ALA intake ratio (p < 0.001). Flaxseed supplementation increased the activity of GSH-Px and decreased the concentration of MDA in milk (p < 0.001). Plasma parameters did not differ among the treatments (p > 0.05). This result indicated that compared with the WF group, GF supplementation in the diet showed higher efficiency in increasing the total n-3 PUFA levels and the milk ALA/ALA intake ratio, and decreased the ratio of n-6 PUFAs to n-3 PUFAs in milk.

Effects of Linseed Supplementation on Milk Production, Composition, Odd- and Branched-Chain Fatty Acids, and on Serum Biochemistry in Cilentana Grazing Goats

The purpose of this study was to investigate the effects of linseed supplementation on milk yield and quality, serum biochemistry and, in particular, to evaluate its possible effects on the production of odd- and branched-chain fatty acids (OBCFA) in the milk of Cilentana grazing goats. Twelve pregnant Cilentana dairy goats were divided into two groups (CTR, control, and LIN, linseed supplementation group). After kidding, the goats had free access to the pasture and both groups received a supplement of 400 g/head of concentrate, but the one administered to the LIN group was characterized by the addition of linseed (in a ratio of 20% as fed) to the ingredients. During the trial, milk samples were taken from April to August in order to evaluate milk production, composition, and fatty acid profile. In addition, blood samples were taken for evaluating the effects of linseed supplementation on goats’ health status. The health status of the goats was not influenced by the linseed supplementation, as confirmed by blood analyses. Concerning the effects on milk, the supplementation positively affected (p < 0.001) milk production and fat percentage and the fatty acid profile was markedly influenced by the lipid supplementation. In particular, milk from the LIN group was characterized by significantly lower concentrations of saturated fatty acids (FA; p < 0.001) and higher proportions of monounsaturated FA, polyunsaturated FA, and conjugated linoleic acids (CLAs) than milk from the CTR group (p < 0.001). In contrast, the OBCFA were negatively influenced by the linseed supplementation (p < 0.0001). Further studies are needed to test the effects of different fat sources and other nutrients on the diets.

Effects of feeding rumen-protected linseed fat to postpartum dairy cows on plasma n-3 polyunsaturated fatty acid concentrations and metabolic and reproductive parameters

High-yielding dairy cows experience a negative energy balance and inflammatory status during the transition period. Fat supplementation increases diet energy density, and plasma n-3 polyunsaturated fatty acids (PUFA) have been proposed to improve immune function. This study tested the hypothesis that dietary supplementation with a rumen-protected and n-3 PUFA-enriched fat could ameliorate both the energetic deficit and immune status of postpartum high-yielding dairy cows, improving overall health and reproductive efficiency. At 11 d in milk (DIM), cows were randomly allocated to groups (1) n-3 PUFA (n = 29), supplemented with encapsulated linseed oil supplying additional up to 64 g/d (mean 25 ± 4 g/d) of α-linolenic acid (ALA), or (2) control (n = 31), supplemented with hydrogenated palm oil without ALA content. Fat supplements of the n-3 PUFA and control groups were available through an automated, off-parlor feeding system, and intake depended on the cow's feeding behavior. Plasma ALA concentrations were higher in n-3 PUFA than control cows, following a linear relation with supplement ingestion, resulting in a lower n-6/n-3 ratio in plasma. Metabolic parameters (body condition score and glucose and β-hydroxybutyric acid blood concentrations) were unaffected, but milk yield improved with increased intake of fat supplements. Plasma total adiponectin concentrations were negatively correlated with ingestion of n-3 PUFA-enriched fat supplement, following a linear relation with intake. Conception rate to first AI increased with higher intake of both fats, but a decrease of calving-to-conception interval occurred only in n-3 PUFA cows. Postpartum ovarian activity and endometrial inflammatory status at 45 DIM were unaffected. In conclusion, this study evinced a positive linear relation between rumen-protected linseed fat intake and plasma n-3 PUFA concentrations, which modulated adiponectin expression and improved reproductive parameters.

Kappa-casein genotyping in tropical milking Criollo and its association to milk production and composition

Caseins are abundant proteins in milk and found in four types (α_S1, α_S2, β, and κ). There is substantial variation in the allelic and genotypic frequencies of the κ-casein gene in different cattle breeds, although the tropical milking Criollo (TMC) has not yet been investigated. The aim was to determine the allelic and genotypic frequencies in the κ-casein gene for two alleles (A and B) in TMC and further investigate its association to milk production and composition. A total of 180 TMC females were genotyped from blood samples. κ-Casein genotyping was performed using restriction fragment length polymorphism (RFLP) after polymerase chain reaction (PCR)-based amplification of genomic DNA. Allele frequencies were 0.39 for A-allele and 0.61 for B-allele (P < 0.05). Genotype frequencies were 0.09 (AA), 0.60 (AB), and 0.31 (BB) (P < 0.05). The κ-casein genotype in TMC cows did not affect milk yield or composition. In sum, the TMC has high frequencies of the B-allele and AB/BB genotypes, although there are no association of such genotypes and milk traits.