Francesca Mazza

Effects of ewes grazing sulla or ryegrass pasture for different daily durations on forage intake, milk production and fatty acid composition of cheese.

Sulla (Sulla coronarium L.) forage is valued for its positive impact on ruminant production, in part due to its moderate content of condensed tannin (CT). The duration of daily grazing is a factor affecting the feed intake and milk production of ewes. In this study, the effects of grazing sulla pasture compared with annual ryegrass, and the extension of grazing from 8 to 22 h/day, were evaluated with regard to ewe forage intake and milk production, as well as the physicochemical properties and fatty acid (FA) composition of cheese. During 42 days in the spring, 28 ewes of the Comisana breed were divided into four groups (S8, S22, R8 and R22) that grazed sulla (S) or ryegrass (R) for 8 (0800 to 1600 h) or 22 h/day, and received no feeding supplement. In six cheese-making sessions, cheeses were manufactured from the 48 h bulk milk of each group. Compared with ewes grazing ryegrass, those grazing sulla had higher dry matter (DM) intake, intake rate and milk yield, and produced milk that was lower in fat and higher in casein. Ewes grazing for 22 h spent more time eating, which reduced the intake rate, increased DM and nutrient intake and milk yield, and reduced milk fat. Due to the ability of CT to inhibit the complete ruminal biohydrogenation of polyunsaturated fatty acids (PUFA), the FA composition of sulla cheese was more beneficial for consumer health compared with ryegrass cheese, having lower levels of saturated fatty acids and higher levels of PUFA and n-3 FA. The FA profile of S8 cheese was better than that of S22 cheese, as it was higher in branched-chain FA, monounsaturated FA, PUFA, rumenic acid (c9,t11-C18:2), and had a greater health-promoting index. The effect of short grazing time on sulla was attributed to major inhibition of PUFA biohydrogenating ruminal bacteria, presumably stimulated by the higher accumulation of sulla CT in the rumen, which is related to a higher intake rate over a shorter eating time. Thus, grazing sulla improved the performance of ewes, thereby increasing, especially with short grazing time, the nutritional properties of cheese fat.

Effects of foal presence at milking and dietary extra virgin olive oil on jennet milk fatty acids profile

Abstract Twelve Ragusana jennets were studied to investigate the effects of dietary extra virgin olive oil and presence of the foal during milking on milk fatty acids (FA) profile. At 20, 50 the and 90 days post-foaling, each jennet was milked 4 times per day. The feeding system and the milking procedures are given by Alabiso et al. (2009). FA profiles of the composites from milkings without foals (1MNF+3MNF) and with foals (2MYF+4MYF) were analyzed by gas chromatography. Dietary oil had no significant effect on milk yield or fat content but increased the proportion of C18:1 (n-9) in milk. Jennet milk had a beneficial FA profile compared to bovine milk and thus would be suitable for consumption by infants suffering from cows milk protein allergy, however, augmentation of the long-chain n-3 polyunsaturated FA content warrants further study.

Legume grain-based supplements in dairy sheep diet: Effects on milk yield, composition and fatty acid profile

With the aim to find protein sources that are free of genetically modified organisms, the effects of legume grain-based concentrates, used as alternatives of a mixed concentrate feed containing soybean, were evaluated on sheep milk production. Twelve lactating ewes were divided into four groups, fed hay and, according to a 4 × 4 Latin square design, supplied with 800 g/day of a commercial mixed concentrate feed (MCF) containing maize and soybean, or the same amount of isoprotein concentrates consisting of chickpea (CH), faba bean (FB), or pea (PE) mixed with barley. The ewes ingested more of the concentrates with legume grains than the MCF (702, 702, 678 vs 587 g/day DM for CH, FB, PE and MCF; P ≤ 0.001). Compared with CH, FB and PE resulted in greater (P ≤ 0.05) milk yield (710, 718 vs 654 g/day for FB, PE and CH, respectively), and led to a greater (P ≤ 0.05) efficiency of dietary protein utilisation for milk casein synthesis (94, 97 vs 87 g casein/kg crude protein intake for FB, PE and CH, respectively), whereas MCF resulted in intermediate levels of milk yield (677 g/day) and milk casein/crude protein intake (88 g/kg). Chickpea increased the milk content of trans-vaccenic and rumenic acids in comparison with FB and PE and, similarly to MCF, increased the milk content of linoleic acid, as well as total unsaturated fatty acids (24.3, 23.9 vs 17.2, 16.8 g/100 g fatty acid methyl esters for MCF, CH, FB and PE; P ≤ 0.001), thereby improving the potential health-promoting index. Legume grains can replace soybean in diets of dairy ewes, as they do not adversely affect milk yield and composition.

A 3-week feed restriction after weaning as an alternative to a medicated diet: effects on growth, health, carcass and meat traits of rabbits of two genotypes

Feed restriction after weaning is widely used in meat rabbit farms to promote health and reduce mortality, but this practice impacts negatively on rabbit growth and slaughter performance. This study compared a 3-week post-weaning feed restriction with ad libitum medicated feeding, evaluating effects on feed intake, growth, health, carcass and meat quality of rabbits of two genotypes: Italian White pure breed and Hycole hybrid×Italian White crossbred. A total of 512 rabbits at 36 days of age, of both sexes and two genotypes, were divided into four homogeneous groups assigned, from 36 to 57 days of age, to different feeding programmes (FP): restricted non-medicated (R-N), ad libitum non-medicated (L-N), restricted medicated (R-M) and ad libitum medicated (L-M). The diets were medicated with oxytetracycline (1540 mg/kg) and colistin sulphate (240 mg/kg). The restriction, performed by giving 70, 80 and 90 g/day of feed for the 1st, 2nd and 3rd week, was followed by ad libitum feeding in the successive 5 weeks, up to slaughter at 92 days of age. Restricted feeds were ingested at a level of 64% of the feed intake recorded in the ad libitum fed rabbits; it was significantly associated, regardless of medication and rabbit genotype, with a lower feed intake (-22 to -24 g dry matter/day) during the entire experiment, compensatory growth and a lower feed conversion ratio in the ad libitum period, and a lower final live weight (-150 g) than ad libitum feeding (P<0.001). During restriction, mortality was lower in the restricted rabbits (6.25%, 5.47% v. 12.5%, 14.8% for R-N, R-M, L-N and L-M; P<0.05), whereas in the ad libitum period mortality did not differ among the groups (9.23%, 9.90%, 11.0% and 4.59% for R-N, R-M, L-N and L-M). Dressing out percentage was not affected by FP or genotype; heavier carcasses were produced by rabbits fed ad libitum (+100 g; P<0.001) and crossbred rabbits (+122 g; P<0.001). Restriction did not alter meat quality, except for a tendency towards a higher cooking loss and less fat; crossbred meat was higher in L* (+1.3; P<0.01) and b* (+0.51; P<0.05) colour indexes and tenderness (-0.14 kg/cm2; P<0.05) than pure breed meat. Under the conditions of this study, a 3-week restricted feeding after weaning resulted to be a suitable alternative, also for high growth potential genotypes, to the antibiotics to preserve rabbit health. The production of lighter carcasses could be compensated partly by the lower feed conversion ratio showed by restricted rabbits.