Recent reports on livestock environmental impact based on life cycle assessment (LCA) did not fully consider the case of the dairy goat. Assignment of an environmental impact (e.g. global warming potential) to a specific product needs to be related to the appropriate ‘unitary amount’ or functional unit (FU). For milk, the energy content may provide a common basis for a definition of the FU. To date, no ad hoc formulations for the FU of goat milk have been proposed. For these reasons, this study aimed to develop and test one or more predictive models (DPMs) for the gross energy (GE) content of goat milk, based on published compositional data, such as fat (F), protein, total solids (TS), solid non-fat matter (SNF), lactose (Lac) and ash. The DPMs were developed, selected and tested using a linear regression approach, as a meta-analysis (i.e. meta-regression) was not applicable. However, in the final stage, a control procedure for spurious findings was carried out using a Monte Carlo permutation test. Because several published predictive models (PPMs) for GE in cow milk and goat milk were found in the literature, they were tested on the same data set with which the DPMs were developed. The best-performing DPMs and PPMs were compared directly with a subset of the individual data retrieved from the literature. Overall, the paucity of direct measurements of the GE in goat milk was a limiting factor in collecting data from the literature; thus, only a small data set (n=26) was established, even though it was considered sufficiently representative of milks from different goat breeds. The three best PPMs based on F alone gave more biased estimates of the GE content of the goat milk than the three new DPMs based on F, F and SNF and F and TS, respectively. Accordingly, three different formulations of FU are proposed, depending on the availability of data including both F and TS (or F and SNF) or F alone. Even though several metrics can be used in defining the FU for milk to be used in LCAs of goat farming systems, the proposed FU formulations should be adopted in place of the similar energy-based ones developed for other dairy species.

The aim of this study was to analyze milk protein composition in purebred and crossbred dairy cattle and estimate the effects of individual sources of variation on the investigated traits. Milk samples were collected from 505 cows from three commercial farms located in Northern Italy, some of which had originated from crossbreeding programs, although most were purebred Holsteins (HO). The basic crossbreeding scheme was a three-breed rotational system using Swedish Red (SR) semen on HO cows (SR×HO), Montbeliarde (MO) semen on SR×HO cows (MO×(SR×HO)) and HO semen again on MO×(SR×HO) cows. A smaller number of purebred HO from each of the herds were mated inverting the breed order (MO×HO and SR×(MO×HO)) or using Brown Swiss (BS) bulls (BS×HO) then MO bulls (MO×(BS×HO)). Milk samples were analyzed by reverse-phase HPLC to obtain protein fraction amounts (g/l) and proportions (% of total true protein). Traits were analyzed using a linear model, which included the fixed effects of herd-test-day (HTD), parity, days in milk and breed combination. Results showed that milk protein fractions were influenced by HTD, stage of lactation, parity and breed combination. The increase in protein concentration during lactation was due in particular to β-casein (β-CN), αS1-CN and β-lactoglobulin (β-LG). The higher protein content of primiparous milk was mainly due to higher concentrations of all casein fractions. The milk from crossbred cows had higher contents and proportions of κ-CN and α-lactalbumin (α-LA), lower proportions of β-LG and greater proportion of caseins/smaller in whey proteins on milk true protein than purebred HO. The three-way crossbreds differed from two-way crossbreds only in having greater proportions of α-LA in their milk. Of the three-way crossbreds, the SR sired cows yielded milk with a smaller content and proportion of β-LG than the MO sired cows, and, consequently, a higher proportion of caseins than whey proteins. Results from this study support the feasibility of using crossbreeding programs to alter milk protein profiles with the aim of improving milk quality and cheese-making properties.

This study was undertaken to provide a thorough analysis of the neutral lipid (NL) and polar lipid (PL) fractions of horse meat that included the content and distribution of acyl and alkenyl moieties in foals under different rearing conditions. Two groups of crossbred horses were studied; the first group was selected from suckling foals produced under grazing conditions and slaughtered at 4 months of age (n=8), and the second group was selected from concentrate-finished foals and slaughtered at 12 months of age (n=7). There were significant differences related to the age and feeding practices of foals which affected the intramuscular (IM) fat content and the fatty acid (FA) composition of NL and PL fractions. Samples from suckling foals were leaner and provided the highest content of methylation products from the plasmalogenic lipids, and total and n-3 polyunsaturated fatty acid (PUFA). By contrast, the meat from concentrate-finished foals had a higher IM fat level resulting in a greater accumulation of 16:0 and total monounsaturated FAs in the NL fraction, whereas the muscle PL fraction retained a similar FA composition between both groups. Linolenic acid was preferentially deposited in the NL fraction, but linoleic acid and the long-chain n-3 and n-6 PUFAs were incorporated into the PL fraction where they served as cell membrane constituents and in eicosanoid formation.

Holstein-Friesian steer beef production is renowned globally as a secondary product of the milk industry. Grass feeding is a common practice in raising Holstein steers because of its low cost. Furthermore, grass feeding is an alternative way to produce beef with a balanced n-6 to n-3 fatty acids (FAs) ratio. However, the performance and meat quality of Holstein-Friesian cattle is more likely to depend on a high-quality diet. The aim of this study was to observe whether feeding two mixed diets; a corn-based total mixed ration (TMR) with winter ryegrass (Lolium perenne) or flaxseed oil-supplemented pellets with reed canary grass haylage (n-3 mix) provided benefits on carcass weight, meat quality and FA composition compared with cattle fed with reed canary grass (Phalaris arundinacea) haylage alone. In all, 15 21-month-old Holstein-Friesian steers were randomly assigned to three group pens, were allowed free access to water and were fed different experimental diets for 150 days. Blood samples were taken a week before slaughter. Carcass weight and meat quality were evaluated after slaughter. Plasma lipid levels and aspartate aminotransferase (AST), γ-glutamyl transpeptidase (GGT), creatine kinase (CK) and alkaline phosphatase (ALP) activities were determined. Diet did not affect plasma triglyceride levels and GGT activity. Plasma cholesterol levels, including low-density and high-density lipoproteins, were higher in both mixed-diet groups than in the haylae group. The highest activities of plasma AST, CK and ALP were observed in the haylage group, followed by n-3 mix and TMR groups, respectively. Carcass weight was lower in the haylage group than in the other groups and no differences were found between the TMR and n-3 mix groups. Although the n-3 mix-fed and haylage-fed beef provided lower n-6 to n-3 FAs ratio than TMR-fed beef, the roasted beef obtained from the TMR group was more acceptable with better overall meat physicochemical properties and sensory scores. According to daily cost, carcass weight and n-6 to n-3 FAs ratio, the finishing diet containing flaxseed oil-supplemented pellets and reed canary grass haylage at the as-fed ratio of 40 : 60 could be beneficial for the production of n-3-enriched beef.

Little is known about cheese-making efficiency at the individual cow level, so our objective was to study the effects of herd productivity, individual herd within productivity class and breed of cow within herd by producing, then analyzing, 508 model cheeses from the milk of 508 cows of six different breeds reared in 41 multi-breed herds classified into two productivity classes (high v. low). For each cow we obtained six milk composition traits; four milk nutrient (fat, protein, solids and energy) recovery traits (REC) in curd; three actual % cheese yield traits (%CY); two theoretical %CYs (fresh cheese and cheese solids) calculated from milk composition; two overall cheese-making efficiencies (% ratio of actual to theoretical %CYs); daily milk yield (dMY); and three actual daily cheese yield traits (dCY). The aforementioned phenotypes were analyzed using a mixed model which included the fixed effects of herd productivity, parity, days in milk (DIM) and breed; the random effects were the water bath, vat, herd and residual. Cows reared in high-productivity herds yielded more milk with higher nutrient contents and more cheese per day, had greater theoretical %CY, and lower cheese-making efficiency than low-productivity herds, but there were no differences between them in terms of REC traits. Individual herd within productivity class was an intermediate source of total variation in REC, %CY and efficiency traits (10.0% to 17.2%), and a major source of variation in milk yield and dCY traits (43.1% to 46.3%). Parity of cows was an important source of variation for productivity traits, whereas DIM affected almost all traits. Breed within herd greatly affected all traits. Holsteins produced more milk, but Brown Swiss cows produced milk with higher actual and theoretical %CYs and cheese-making efficiency, so that the two large-framed breeds had the same dCY. Compared with the two large-framed breeds, the small Jersey cows produced much less milk, but with greater actual and theoretical %CYs, similar efficiencies and a slightly lower dCY. Compared with the average of the specialized dairy breeds, the three dual-purpose breeds (Simmental and the local Rendena and Alpine Grey) had, on average, similar dMY, lower actual and theoretical %CY, similar fat and protein REC, and slightly greater cheese-making efficiency.