S. Bovolenta

The n-alkane concentrations in buds and leaves of browsed broadleaf trees

The concentration of n-alkanes in the cuticular wax of plants can be used to estimate the composition of the diet selected by free-ranging animals. The aims of this study were to characterize the n-alkane profiles of developing leaves and evaluate the degree of chemical discrimination between six browsed broadleaf, tree species: European ash (Fraxinus excelsior L.), flowering ash (Fraxinus ornus L.), hornbeam (Carpinus betulus L.), hazel (Corylus avellana L.), mountain ash (Sorbus aucuparia L.) and beech (Fagus sylvatica L). The effect of the stage of development was examined by considering five different vegetative stages: dormant bud (DB), late bud (LB), young leaf (YL), mature leaf (ML) and senescing leaf (SL). Five samples per each vegetative stage and species, gathered in a mixed woodland of the Italian Eastern Alps between February and October, were analysed for their n-alkane concentrations (C 23 -C 36 ). The residual coefficient of variation was 15.5 % on average for the individual n-alkanes considered. There were noticeable differences in individual and total n-alkanes content between species. In particular, C 27 was the predominant n-alkane in beech and C 33 was found in high proportions in the two species of Fraxinus; hazel and flowering ash had a higher total n-alkanes content than the overall mean, while the lowest values were found in hornbeam and beech. The n-alkane profile also underwent important changes during the vegetative development, with different extent and direction according to the species. In the three successive leaf stages, a tendency for a progressive increase in the longest chain homologues was observed. In any case, the young leaf stage differed most from the contiguous stages. Canonical discriminant analysis indicated that the n-alkane profile of buds and leaves were mathematically distinguishable and the chemical differences between species were persistent over the plant vegetative development.

Comparison of n-alkanes and chromium oxide methods for estimating herbage intake by grazing dairy cows

The experiment was conducted on an alpine pasture composed predominantly of gramineae (more than 62% of ground cover) with 18 lactating Brown Swiss cows (average yield 21.0 kg FCM, SD 3.14), which received a supplement of concentrates according to their milk production (range 1.5–8.0 kg day−1). Herbage intake was estimated for all the animals with the chromium oxide method (twice-daily dosing), associated with the in vitro OM digestibility, and with the n-alkane method, using C31 as the internal marker and C32 as the external marker (once-daily dosing). The sampling of the herbage by hand plucking and the faeces (four grab samples per day) was performed for 5 consecutive days. In order to evaluate the variability of the markers excretion, the daily samples of faeces from six animals were analysed separately. The repeatability within day of the faecal concentration of the n-alkanes was higher than that for the chromium oxide (0.41, 0.48 and 0.55 for C31, C32 and the C31C32 ratio, respectively vs. 0.18 for the chromium oxide). The highest proportion of the variation in the estimated intake was associated with the differences between days for the n-alkane method (54.6% of the total), while the samplings within days were more important for the chromium oxide technique (67.0% of the total). On average, herbage intake estimated with the two methods coincided if the recovery of the chromium oxide was assumed to be 95.5%. The correlation between estimates was 0.62∗∗ and did not appear to be influenced by the level of concentrates in the diet. Considering the mode of executing the two methods under comparison, it was concluded that the n-alkane technique is easier to perform and less laborious.

Effect of whole linseed addition on meat production and quality of Italian Simmental and Holstein young bulls

The effect of long term dietary linseed addition on performance, carcass characteristics and meat quality of Italian Simmental (IS) and Italian Holstein (HI) young bulls was investigated. Thirty-two animals were assigned to 4 groups following a factorial design: 2 breeds - IS and IH - ×2 diets - containing whole ground linseed (5-8% of DM) and control. IS had greater in vivo performance and carcass characteristics than IH. IS muscle had lower C14:0, C16:0, SFA, higher C18:2n-6 cis, PUFAn-6, PUFA and PUFA/SFA proportion than IH in phospholipids (PL) fraction. Linseed inclusion did not affect animals performance and carcass characteristics. In muscle PL, linseed increased C20:0, C22:0, C23:0, C20:5n-3 and decreased C20:4n-6, PUFAn-6/n-3, PUFAn-6 concentration. Linseed decreased C14:0, C16:0 proportion in neutral lipids (NL) and increased total PUFAn-3, C18:3n-3 proportions both in NL and PL fraction. However, these differences were relatively low from a quantitative point of view.

Association analyses of single nucleotide polymorphisms in the LEP and SCD1 genes on the fatty acid profile of muscle fat in Simmental bulls

The aim was to investigate the effect of the genetic polymorphisms of leptin (LEP) and stearoyl-CoA desaturase (SCD1) genes on the fatty acid (FA) composition of the muscle of 103 Simmental bulls. Ten single nucleotide polymorphisms (SNP) were detected in exons 2 and 3 of the LEP gene, two of them encoding non-synonymous mutations. Allelic substitution effects of all the SNP on 28 single fatty acids, monounsaturated (MUFA) and polyunsaturated (PUFA) and desaturation indexes were estimated. Both the SCD1 SNP, as well as three SNP of the leptin gene, affected, to different extents, the desaturation of FA into MUFA. Because it was previously proposed that leptins metabolic action involves down-regulation of SCD1, it is possible that, beyond the mere additive effect of SCD1 gene on FA desaturation, the non-synonymous mutations in the leptin gene also contribute to the variability of FA composition in muscle fat.

Environmental sustainability of Alpine livestock farms

The 2006 FAO report concerning the environmental impact of the livestock sector has generated scientific debate, especially considering the context of global warming and the need to provide animal products to a growing world population. However, this sector differs widely in terms of environmental context, production targets, degree of intensification and cultural role. The traditional breeding systems in the Alps were largely based on the use of meadows and pastures and produced not only milk and meat but also other fundamental positive externalities and ecosystem services, such as conservation of genetic resources, water flow regulation, pollination, climate regulation, landscape maintenance, recreation and ecotourism and cultural heritage. In recent decades, the mountain livestock, mainly represented by dairy cattle, has been affected by a dramatic reduction of farms, a strong increase of animals per farm, an increase in indoor production systems, more extensive use of specialised non-indigenous cattle breeds and the increasing use of extra-farm concentrates instead of meadows and pastures for fodder. This paper firstly describes the livestock sector in the Italian Alps and analyses the most important factors affecting their sustainability. Secondly, it discusses the need to assess the ecosystem services offered by forage-based livestock systems in mountains with particular attention to greenhouse gas emission and its mitigation by carbon sequestration. In conclusion, comparison between the different elements of the environmental sustainability of mountain livestock systems must be based on a comprehensive overview of the relationships among animal husbandry, environment and socio-economic context.

Comparison of n-alkanes or chromium oxide methods for estimation of herbage intake by sheep

Abstract Herbage intake (HI) was estimated with two procedures: (a) with the n -alkanes method (HI al ), which combines the use of odd-chain n -alkanes, naturally occurring in plants, and dosed even-chain n -alkanes, as internal and external markers, respectively; (b) with the ratio between faecal excretion, estimated with chromium sesquioxide (Cr 2 O 3 ), and the herbage indigestibility, estimated in vitro (HI Cr ). The two techniques were compared in an indoor experiment and under grazing conditions. In the indoor trial, 12 wethers were fed 40 g dry matter (DM) kg −1 BW 0.75 day −1 of one of the following diets: herbage only (diet H); herbage plus maize (diet M; 26% of DM intake); herbage plus maize plus maize gluten meal (diet MG; 13% of DM intake each). Each wether was dosed once a day for 12 days with the external indicators impregnated on paper and inserted in gelatine capsules: n -dotriacontane, C 32 , 600 mg day −1 ; Cr 2 O 3 , 500 mg day −1 . In the second experiment, six adult, lactating ewes grazing the pasture used for the indoor trial were divided into groups of three receiving 700 g day −1 of two different supplements: maize (diet M) or a 50:50 mix of maize and maize gluten meal (diet MG). The external indicators (Cr 2 O 3 and C 32 ) were administered for 8 consecutive days. The trial was repeated four times with the same procedure between 10th and the 40th day after lambing. Recoveries of Cr 2 O 3 , C 32 and herbage n -alkanes ( n -hentriacontane, C 31 , and n -tritriacontane, C 33 ) were incomplete, with lower values for the natural n -alkanes than the dosed n -alkane (Cr 2 O 3 , 94.9 ± 5.5%; C 31 , 86.7 ± 8.7%; C 32 , 89.6 ± 8.5%; C 33 , 85.1 ± 9.9%). Therefore, HI Cr gave an overestimate of the true herbage intake of 5.5% and HI al an underestimate of 3.0%, with a significant discrepancy between methods (803 vs. 733 g organic matter (OM) day −1 ), not affected by diet. In the grazing trial, HI Cr was higher than HI al , but the difference between methods (1503 vs. 1273 g OM day −1 ) was higher than that obtained in the indoor experiment and was influenced by diet (380 g OM day −1 vs. 81 g OM day −1 with diet M and diet MG, respectively). A possible explanation of the different results obtained indoor or at pasture is discussed.

Variability of n-alkane content in a natural pasture and in faeces of grazing dairy cows

Abstract The experiment was conducted on a natural alpine pasture with six dairy cows grazing for two periods of 15 days each in continguous sectors. Three animals only had access to the pasture (Treatment P) while the other three received 3 kg concentrates per day (Treatment PC). Each animal was dosed daily with a pellet containing an average of 1084 mg of C32 on a paper support. During the last 6 days of each experimental period, four faecal grab samples per day were taken from each animal and later mixed to form individual daily samples. For 3 days in succession, the four samples from one animal per treatment were held separate. The botanical composition of the pasture was expressed as a percentage of the average area covered by the various families and species. The concentration of the n-alkanes in the pasture herbage was measured, for each grazing period, in samples collected from protected areas at the beginning and end of each grazing period. The n-alkanes were also determined in the concentrates and, for C32, in the pellets. The pasture had a considerable variability both in terms of the number and distribution of the plant families and species and the content of the n-alkanes. The variability of the concentration of C32 in the dosed pellets was very low. The concentration of n-alkanes in the faeces was influenced by the grazing zone while the diet factor had a significant interaction with the days of sampling. The diurnal variations in the faecal concentrations were lower than the variations between days. The comparison between the concentrations obtained from one, two, three or four daily samples showed that one or preferably two samples supplied the same information as four samples. The presence of concentrates in the diet reduced the diurnal variability of almost all the n-alkanes considered.

Effect of rearing system (mountain pasture vs. indoor) of Simmental cows on milk composition and Montasio cheese characteristics.

Dairy cattle in the Alps are traditionally maintained on high altitude pastures during summer. In recent decades, however, many farmers prefer to maintain the cows always indoor with a hay-based diet. Many authors have shown that the forage type is able to modify the characteristics of milk and cheese. Recently the product specification of PDO Montasio allowed differentiation between mountain cheeses and other products. Aim of this trial is to study the effect of rearing system on the characteristics of milk and cheese produced in this context. One hundred and twenty Simmental dairy cows were considered, 60 grazed on high altitude pasture, and 60 kept indoor and fed a hay-based diet. Cheese production was repeated in two periods (early July and late August) and ripened two and six months. Pasture-derived milk and cheese presented higher fat and lower protein content than hay-derived ones. Rearing systems also affected cheese colour. Textural parameters, hardness, gumminess and chewiness were found to be higher in pasture-derived cheese. In addition, it showed lower level of total saturated fatty acids, and higher level of mono and polyunsaturated fatty acids than hay-derived cheeses. Consumers perceived the difference of cheeses in terms of colour and holes, but they express a similar overall liking. More limited effects of period and ripening time were observed.

Effect of linseed addition on the expression of some lipid metabolism genes in the adipose tissue of young Italian Simmental and Holstein bulls

The objective of this trial was to determine the effect of breed and long-term dietary linseed addition on composition of fatty acids and expression of some genes involved in the lipid metabolism within subcutaneous (s.c.) adipose tissue of young bulls. Italian Simmental and Holstein bulls (n=16/breed) were fed a corn silage-grass hay diet with or without 8% (DM basis) whole ground linseed. Inclusion of linseed, rich in α-linoleic acid (C18:3n-3), increased (P<0.05) the proportions of linolelaidic (C18:2n-6trans), γ-linolenic (C18:3n-6), C18:3n-3, and rumenic (cis9,trans11 conjugated linoleic acid) acids, as well as total n-3 fatty acid, total PUFA, and PUFA:SFA, but decreased (P<0.05) weight percentages of myristic (C14:0), pentadecanoic (C15:0), palmitic (C16:0), palmitelaidic (C16:1n-9trans), and margaric (C17:0) acids, along with n-6:n-3, in the s.c. fat of young bulls. Even though PUFA were similar (P≥0.23) between bull breeds, s.c. fat from Holstein bulls had greater (P<0.05) proportions of tridecylic (C13:0), myristoleic (C14:1) and palmitoleic (C16:1n-9cis) acids and a lower (P<0.05) proportion of margaric (C17:0) acid than s.c. fat from Simmental bulls. Feeding linseed decreased (P<0.05) the expression of stearoyl CoA desaturase (SCD) and the lipoprotein lipase (LPL) gene without affecting (P≥0.19) fatty acid synthase (FASN), leptin (LEP), and PPARγ2 mRNA in the s.c. fat of bulls; however, there was no effect of bull breed (P≥0.11) or interactive effect of breed and linseed (P≥0.23) on gene expression. Expression of PPARγ2 was positively correlated with SCD (r=0.454; P=0.01), LEP (r=0.500; P<0.01), and LPL (r=0.531; P<0.01) mRNA, indicating that PPARγ2 increases the expression of genes involved in lipogenesis.

Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i) four weeks before grazing during the indoor period in the stall; (ii) about three weeks after the start of grazing; and (iii) in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tiestalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L) and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.