Effect of the dam’s feeding regimen on the meat quality of light suckling lambs

In order to verify the effect of the introduction of concentrates without GMO risk and at low aflatoxin risk in the diet of grazing milk ewes on the quanti-qualitative production of meat of their milk-fed light lambs, two trials were carried out - in Sicily, on 32 Comisana lambs, slaughtered at 49±4 days (trial 1); and in Sardinia, on 28 Sarda lambs, slaughtered at 31±4 days(trial 2) - comparing the following grazing dams’ feeding regimes: High stocking rate + Organic (barley – tickbean or pea) Concentrate (HO); High stocking rate + Conventional (maize-soybean) Concentrate (HC); Low stocking rate + Organic Concentrate (LO); Low stocking rate + Conventional Concentrate (LC). Lamb performances, carcass quality, meat colour and lipid content were not modified by dam’s feeding regimen. However, significant differences were observed in the fatty acid (FA) composition of the intramuscular fat of the older suckling lambs of trial 1. The main variation concerned n-3 polyunsaturated FAs and conjugated linoleic acids

Effect of different pastures on CLA content in milk and sheep cheese

It is known that milk composition included conjugated linoleic acid (CLA) is affected by animal feeding system (Cabiddu et al., 2001). In Sardinia dairy sheep feeding is mainly based on pastures. Most of them are characterised by self-regenerating species, like annual ryegrass (Lolium rigidum Gaudin) and burr medic (Medicago polymorpha L.). Non conventional species belonging to the Compositae family such as (Chrysanthemum coronarium L.) seem interesting for sheep feeding when other herbages decrease in quality (late spring- early summer). It was observed that C. coronarium establishes rapidly, can be grazed early in the growing season and persist where other pasture species may disappear; for these reasons it can be considered a valuable source of food. Moreover a preliminary study with dairy sheep fed fresh forage of C. coronarium showed relatively high levels of CLA in milk (Molle G. pers. com.) The aim of the present work was to study the influence of different pastures on milk composition, with particular reference to CLA and its precursors

Re-visiting the nutrition of dairy sheep grazing Mediterranean pastures

In the light of recent findings in sheep nutrition and behaviour, the diets of grazing dairy sheep should be based on forages encompassing a variety of complementary nutritional values and containing moderate levels of complementary plant secondary metabolites, until recently regarded as "anti-nutritional". In lactating sheep, pastures of tannin-containing legumes like sulla (Hedysarum coronarium) and chicory (Cichorium intybus) can be integrated with annual grasses for establishing sustainable artificial pastures under rainfed conditions. Diets based on these forages, while ensuring high milking performance, can mitigate the unbalance of CP to energy ratio of grazing sheep. By grazing sulla and annual or Italian ryegrass (50:50 by area) as spatially conterminal monocultures or in timely sequence (complementary grazing) sheep eat more and perform better than by grazing the ryegrass pasture only. Concentrate supplementation of lactating sheep should be preferably based on fibrous sources (soyhulls or beet pulps), particularly from mid-lactation onwards and when supplementation levels are high. Milk urea concentration is confirmedly a useful monitoring tool to balance protein nutrition and curb the waste of N at animal and system level

Ingestive behaviour and performances of dairy ewes part-time grazing Mediterranean forages

Part-time grazing, i.e. restricted time access to pasture, is widespread but its effects on ingestive behaviour and performance of dairy ewes are still overlooked. The objectives of this thesis were: i) reviewing the literature focused on the effects of part-time grazing on ingestive behaviour and performance of ruminants and horses; ii) assessing the effects of different time restrictions on the above variables in milked ewes grazing Lolium multiflorum Lam (experiment 1) and Trifolium alexandrinum L (experiment 2); and iii) modelling the results of the above experiments for predicting herbge intake. The review showed that part-time grazing of pastures by ruminants results in compensatory behaviours such as higher intake rate and grazing intensity and lower energy expenditures, which often bring about mild to nil performance losses as compared with time-unrestricted grazers. Horese are less able in this compensation than ruminants. The experiments on dairy ews compared 2, 4, and 6 h/d time access to pasture. Their results confirmed the general trend of ingestive behaviour, showing that giving access to a moderate quality Italian ryegrass for less than 6 h/d decreased intake and milk yield of ewes in mid lactation, whereas for berseem clover access could be as short as 4 h/d without any loss of intake and performance. The modelling of the data based on both stepwise and partial least square regressions provided good performance in validation and satisfactory sensitivity

Effect of the dam's feeding regimen on the meat quality of light suckling lambs

In order to verify the effect of the introduction of concentrates without GMO risk and at low aflatoxin risk in the diet of grazing milk ewes on the quanti-qualitative production of meat of their milk-fed light lambs, two trials were carried out - in Sicily, on 32 Comisana lambs, slaughtered at 49±4 days (trial 1); and in Sardinia, on 28 Sarda lambs, slaughtered at 31±4 days(trial 2) - comparing the following grazing dams' feeding regimes: High stocking rate + Organic (barley – tickbean or pea) Concentrate (HO); High stocking rate + Conventional (maize-soybean) Concentrate (HC); Low stocking rate + Organic Concentrate (LO); Low stocking rate + Conventional Concentrate (LC). Lamb performances, carcass quality, meat colour and lipid content were not modified by dam's feeding regimen. However, significant differences were observed in the fatty acid (FA) composition of the intramuscular fat of the older suckling lambs of trial 1. The main variation concerned n-3 polyunsaturated FAs and conjugated linoleic acids

Effect of corn and beet pulp based concentrate on ruminal parameters in wethers fed with fresh forage

Four wethers housed in individual pens and fitted with ruminal cannulae were grouped (two wethers per group) and fed fresh forage (Italian ryegrass, Lolium multiflorum) with either beet pulp (BP) or corn based concentrate (C) as supplements, using a crossover experimental design. The experiment was carried out during two experimental periods: the growing phase (early spring, G) and the reproductive phase (late spring, R) of the ryegrass. The diet of each animal was changed as the grass moved from the vegetative phase to the reproductive phase. The intake, the chemical composition of the diet and ruminal parameters such as pH, ammonia and volatile fatty acid were determined. Total dry matter intake (DMI) decreased from early to late spring (1081 vs 767 g/d; P<0.0001). Herbage DMI in particular decreased more (811 vs 543 g/d; P<0.05) than concentrate DMI (271 vs 224 g/d; P<0.054). There were marked differences in the chemical composition of the diet in wethers fed with the forage from early or late spring. This was because of changes in the characteristics of the forage. In detail, DM, NDF and ADF increased from early to late spring while CP, and EE decreased (P<0.05). Ruminal pH was lower in G than in R (6.24 vs 6.57, P<0.05). The concentrate used had no effect on the pH value. The ammonia concentration in the rumen fluid decreased from early to late spring (10.79 vs 6.68 mg/100 ml, P<0.05) and it was not influenced by the source of carbohydrates from the concentrate. VFA rumen fluid concentration increased (P<0.05) after feeding and decreased before the second meal. In the rumen fluid, the maximum total VFA concentration and the lowest pH were observed 2 h after the morning meal. Acetate and butyrate concentrations in the rumen fluid were influenced by the period (P<0.05) but not by the concentrate source. By contrast, the concentrate source significantly influenced the rumen fermentation patterns of propionate and VFA ratios, with higher propionic acid and lower acetate to propionate ratios in C than BP. This highlights the importance of the carbohydrate source in supplements for pasture based rations which varied according to the proportion of beet pulp and corn in the ingested diet

The effect of parity number on the metabolism, inflammation, and oxidative status of dairy sheep during the transition period.

The objective of this study was to evaluate whether dairy sheep during the transition period are affected by their parity numbers with regard to (1) body weight (BW), body condition score (BCS), and production performance (milk yield and composition) and (2) metabolic, inflammation, and stress biomarkers. For this purpose, 30 Sarda dairy ewes [15 primiparous (PRP) and 15 multiparous (MUP) ewes] were recruited on d 90 of gestation. Each group was homogeneous according to age, BW, and BCS. Sampling was carried out at -60, -30, -7, 0, +30, and +60 d from lambing. The MUP ewes showed a higher BW (46.32 vs. 38.71 kg) and larger litter size (1.45 vs. 1.06 kg) but a lower BCS (2.47 vs. 2.70) than the PRP ewes. Furthermore, the MUP ewes had lower concentrations of glucose (3.49 vs. 4.27 mol/L), cholesterol (1.63 vs. 1.81 mmol/L), free fatty acids (0.47 vs. 0.62 mmol/L), and triglycerides (0.22 vs. 0.25 mmol/L) compared with PRP ewes. With regard to inflammation and oxidative stress parameters, the PRP group had higher haptoglobin (0.48 vs. 0.18 g/L) and paraoxonase (187.90 vs. 152.11 U/L) activity than the MUP group. Overall, the MUP ewes were characterized by greater milk production performance and greater feed intake, resulting in a better energy balance, than the PRP ewes. Interestingly, these findings highlighted a different metabolic and inflammatory response over the transition period between PRP and MUP ewes, with the latter displaying lower concentrations of inflammatory-related biomarkers

Palatability of \u3cem\u3ePsolarea\u3c/em\u3e spp. Accessions Offered as Micro-Swards to Dairy Sheep

Psoralea bituminosa C.H. Stirton (syn. Bituminaria bituminosa L.) is a perennial legume usually considered of low palatability because of the strong smell that can be emitted by oil glands located on its foliage. However the nutritive value of P. bituminosa in terms of forage composition and digestibility was proven similar to or even better than that of other legumes. The aerial part of this species may contain a high concentration of furano-coumarins, out of which psoralen and angelicin are the most abundant (Pecetti et al. 2007). These substances could be harmful to animals, being responsible for contact photodermatitis, in addition to possibly limiting forage intake. Nevertheless there are some examples of the utilisation of P. bituminosa either as green or dry forage. In the Canary Islands, it is grazed all year and also is collected from late spring to mid-summer to make hay used to feed goats (Ventura et al. 2009). In Israel P. bituminosa is grazed by cattle in particular in mid-spring, when the principal grasses become less palatable. In late spring, when the herbaceous species dry up, P. bituminosa becomes the only species with green leaves and cattle graze the whole plant intensively (Sternberg et al. 2006). The potentiality of Psoralea as forage species for dairy sheep is less known. For that reason an experiment was carried out to evaluate the propensity of Sarda dairy sheep towards different accessions of Psoralea spp. using the micro-swards method (Orr et al. 2005)

Models for estimating feed intake in small ruminants

This review deals with the most relevant limits and developments of the modeling of intake of sheep and goats reared intensively and extensively. Because small ruminants are normally fed ad libitum, voluntary feed intake is crucial in feeding tactics and strategies aimed at optimal animal production. The effects of genetic, neuroendocrine, hormonal, feed and environmental factors on voluntary feed intake were discussed. Then, several mathematical models to estimate dry matter intake (DMI) were examined, with emphasis on empirical models for sheep and goats in intensive farm systems or in extensive areas under pasture or rangeland conditions. A sensitivity analysis of four models of prediction of DMI in housed lactating dairy sheep and meat sheep breeds was also presented. This work evidenced a large variability in the approaches used and in the variables considered for housed sheep and goats. Regarding the estimation of feed intake for grazing sheep and browsing goats, the accuracy of estimates based on empirical models developed so far is very low when applied out of the boundaries of the studied system. Feeding experiments indoors and outdoors remain fundamental for a better modeling and understanding of the interactions between feeds and small ruminants. However, there is a need for biological and theoretical frameworks in which these experiments should be carried out, so that appropriate empirical or mechanistic equations to predict DMI could be developed

Role of sensorial perceptions in feed selection and intake by domestic herbivores

Sensorial perceptions play an important role in feed selection and intake by herbivores. Much research has been carried out to study the sensorial perceptions evoked by forages and their effects on intake and feed selection. Certain specific compounds are clearly able to evoke positive or negative sensorial perceptions when forages are eaten. This might lead to the development of plant extracts and aromas that might be used to improve the intake of unpalatable feeds. In the case of concentrates, the little research available seems to support an important role of the interaction between sensorial perceptions and post-ingestive effects when simple unmixed concentrates are supplied. It is not clear to what extent these effects are important when compound concentrates are offered. Despite these advances, it appears that most of the research carried out so far has been exploratory and observational. More research is needed to better understand the mechanisms underlying feed palatability before it can be included in intake prediction models