Sarda Sheep Research Articles

Environmental monitoring of Listeria monocytogenes contamination in dairy processing facilities combining culturing technique and molecular methods

Objectiveof the present study was to investigate Listeria contamination in Sardinian sheep cheese-making plants using culture and DNA-based methods. Food and environmental samples were collected from different surfaces of 14 facilities. Samples were collected using pre-moistened sponge swabs. Each site was sampled using two sponges used one for microbiological detection and the other for extraction of total DNA. The DNA was submitted to real time PCR targeting the prs gene for Listeria spp., the gene inlA for Listeria monocytogenes and the gene iap for Listeria innocua. DNA metabarcoding was also conducted on the total DNA. Overall were collected 254 environmental and 36 food samples. The prevalence of Listeria spp. and Listeria monocytogenes was 18.6% and 10.0%, respectively. Samples enrichment coupled with quantitative PCR (qPCR) showed a greater sensitivity than the conventional culture method with an overall prevalence of 12.1% for L. monocytogenes. Both, qPCR and ribosomal DNA-metabarcoding conducted on total DNA extracted from the sponges performed poorly in comparison to the culture-based method detecting the presence of Listeria genus in as little as 7 (2.4%) and 4 (1.4%) samples respectively. The present study supports the use of a culture enrichment coupled with qPCR for routine monitoring of contamination in food premises.

Looking for the ecological transition of Mediterranean small ruminant sector. Characterization and main drivers of environmental performance of the Sardinian sheep farming systems

A Life Cycle Assessment (LCA) study was carried out to assess the environmental profile of the main Sardinian dairy sheep farming systems, with the scope to provide a detailed and robust baseline for the identification of effective mitigation solutions at farm level and to develop environmental strategies at regional scale. Both product- and area-based functional units (FUs) were adopted, considering sixteen impact categories and soil carbon sequestration estimates as well. Water Use, Climate Change, Land Use, Ecotoxicity Freshwater, Marine Eutrophication and Fossils Resource Use resulted the main impact categories, cumulatively contributing over 80% of the total environmental impact (single score). Environmental performances significantly varied according to the geo-pedological traits of the different sheep milk production areas and were driven by the farming systems’ structure and production level. The group of farms located in less fertile areas showed significantly worse environmental performance per kg of normalized milk for the impact categories Climate Change and Land Use, whereas no significant differences were observed for the remaining main impact categories. Considering the area-based FU, this farm group resulted less impacting for all main categories compared to the group of farms located in more plain and productive soils, with a significantly lower impact observed for Marine Eutrophication and Fossils Resource Use. Regardless of the FU used, feed supply management represented a key area of improvement, and soil carbon sequestration impact compensated the high GHG emission intensity of grassland-based farms despite the limited nutritional value of natural pasture. Regional strategies should be based on ecosystem services optimization and eco-innovative solutions tailored according to both the specific geo-pedological conditions and the production level of each farming system.

Massese, Sarda and Lacaune Dairy Sheep Breeds: An Environmental Impact Comparison

The dairy sheep sector is an important sector in semiarid and arid areas. So far, the environmental impact of sheep milk production in these areas is scarcely known. This study aimed to assess the environmental impact of milk production on three farms that differ in the breed reared, namely Sarda (S), Lacaune (L) and Massese (M), in Tuscany (a Mediterranean region in central Italy). The Life Cycle Assessment methodology was applied to calculate the environmental performance of the farms, and the following impact categories were studied: climate change, freshwater, marine and terrestrial eutrophication, acidification, water use and land use. The L farm showed the lowest values for most impact categories and the M farm the highest. These results can be attributed to the greater productivity and efficiency of the L breed compared to the other two. Only for water use did the M farm cause a lower impact, underscoring the importance of applying characterization factors at the sub-watershed level.

Detection of selective sweep in European wild sheep breeds.

In wild animal populations, there is a differentiation between populations due to natural selection. The direction and pressure of natural selection in the wild sheep are different in the various geographic areas. Linkage disequilibrium studies showed that regions of the genome in whole wild sheep are under natural selection and that natural selection can affect immune or reproductive or metabolic traits. The study aimed to identify genomic regions under natural selection in wild sheep. For this purpose, the genetic information of 24 European wild sheep and 24 Sardinian wild sheep was used. The genotypes were determined using Illumina 50K SNPChip arrays based on Oar_4.0 version of the sheep genome. After quality control steps, finally, 31,560 SNP markers were analyzed. The value of LD was calculated by calculating the r2 statistic between all pairs of locations through PLINK software. To identify signs of selection based on linkage disequilibrium methods, an extended haplotype homozygosity test of XP-EHH crossing population and iHS intrapopulation was used. The results of iHS studies showed that in European and Sardinian wild sheep, the highest iHS coefficient under natural selection was observed on 3 and 2 chromosome numbers, respectively. Also, the results of XP-EHH studies showed that the largest XP-EHH coefficients under natural selection in European wild sheep compared to Sardinian and vice versa in Sardinian wild sheep compared to European wild sheep were observed on 3 and 16 chromosome numbers, respectively. In addition, the results of gene cycle studies showed that COPB1, SEC24D, ZDHHC17, BBS4, RFX3, SLC26A8, CAMK2D, GRIA1, GRM1, GRID2, PPP2R1A, CPEB4, PLEKHA5 and KIF13A, VPS39, VPS53, DTNBP1, DYNC1I1, FAM91A genes are under natural selection in Sardinian and European wild sheeps, respectively. The direction and selection pressure of natural selection in the two breeds of wild sheep is different due to different geographic conditions.

Technological and Safety Characterization of Coagulase-Negative Staphylococci Isolated from Sardinian Fermented Sausage Made by Ovine Meat.

Ripened sheep sausages are widely consumed in Italy, particularly in Sardinia. Despite their driving role in flavor and color development, coagulase-negative staphylococci in these products have been rarely investigated. A total of 70 CoNS cultures isolated from Sardinian sheep sausages were characterized by rep-PCR and M13-RAPD typing and identified by 16S rDNA sequencing. S. xylosus and S. equorum accounted for more than 70% of the total isolates, whilst S. pasteuri (8.5%), S. succinus (2.8%), and S. haemolyticus (2.8%) were less represented. The genes encoding the synthesis of putrescine, tyramine, cadaverine, and histamine were evaluated by PCR. None of the strains hosted genes for decarboxylases, except one S. pasteuri strain that was potentially a tyramine-producer. Antibiotic resistance was evaluated, along with nitrate reductase, lipolytic, and proteolytic activity, in a pool of selected cultures. Resistance to the primary antibiotics was rather widespread. S. xylosus, S. equorum, and S. pasteuri strains were all resistant to amoxicillin and kanamycin. S. equorum strains were sensitive to all tested antibiotics. S. xylosus strains were all resistant to penicillin B. Conversely, all S. pasteuri strains were resistant to both ampicillin and penicillin B, and four out of five strains exhibited tetracycline resistance. The high variability in the production of sheep sausages makes the search for adjunct cultures of crucial relevance. According to this perspective, the characterization of the autochthonous CSN population represents the first step to approach a starter selection.

Economic and Environmental Sustainability Trade-Off Analysis in Sheep Farming Using the Farm Accountancy Data Network Database

Agriculture and livestock farming significantly contribute to the success of all United Nations Sustainable Development Goals of Agenda 2030 and are pivotal in the sustainability transition of the European agri-food sector. However, those sectors have been criticized for generating negative environmental externalities. In this context, adopting indicators able to evaluate agriculture and sheep farming sustainability is essential for fostering sustainable development in the primary sector and defining appropriate policies to support it. Such indicators are crucial for understanding if European Union policies striving to realize win–win opportunities based on synergy between farms’ environmental and economic dimensions are realistic. This paper focuses on this wave of interest and has two aims. First, it intends to investigate the existence of synergies or trade-offs between those dimensions using a trade-off analysis. To this end, a significant set of economic and environmental farm indicators was selected, and two composite indicators were created. Second, it aims to investigate the relationship between those two indicators and some pivotal structural and socio-demographic variables. This study was carried out on 219 Sardinian sheep farms included in the Italian Farm Accountancy Data Network. The findings showed a low synergy between the economic and environmental spheres, a relationship between economic indicators and farmers’ ages and organic production variables, and no relationships between the environmental dimension and the analyzed variables.

Development and Chemico-Physical Characterization of Ovine Milk-Based Ingredients for Infant Formulae

The great majority of infant formula (FM) for neonate’s nutrition are produced using ingredients from cow milk. Recently, some countries, such as China and New Zealand, are turning their attention to the use of ovine milk ingredients for FM production. In this study, a pilot plant process has been set up to produce infant formula ingredients from Sarda sheep milk. To meet the nutritional needs of neonates (0–6 and 6–12 months of age) two different liquid milk-derived formulations (IF1 and IF2, respectively) obtained mixing whole milk, skimmed milk, and whey milk ultrafiltration concentrate (retentate) were produced. Compositional analysis of milk, retentate, and the final IFs showed that the two formulations contain elements of nutritional interest, such as well-balanced content of high biological value proteins (casein:whey proteins ratio of 30:70 and 60:40 for IF1 and IF2, respectively), vitamin A, E and B5, cholesterol, minerals, nucleotides, free amino acids and essential fatty acids (n–6:n–3 ~1), compatible with the growth and development needs of neonates. Therefore, the obtained IF1 and IF2 can be proposed as valuable ovine dairy ingredients for FM manufacturing. Further studies will be necessary to verify the adaptability of the developed process from laboratory to industrial scale application.

Impact of Pasture-Based Diets on the Untargeted Metabolomics Profile of Sarda Sheep Milk.

In this work, untargeted metabolomics was used to shed light on the impact of different pasture-based diets on the chemical profile of Sarda sheep milk. The study considered 11 dairy sheep farms located in Sardinia, and milk samples were collected in 4 different periods, namely January, March, May, and July 2019, when all sheep had 58, 98, 138, and 178 days in milk, respectively. The animal diet composition was based on the intake of grazed herbage in natural pasture, hay, and concentrate. Overall, the combination of two comprehensive databases on food, namely the Milk Composition Database and Phenol-Explorer, allowed the putative identification of 406 metabolites, with a significant (p < 0.01) enrichment of several metabolite classes, namely amino acids and peptides, monosaccharides, fatty acids, phenylacetic acids, benzoic acids, cinnamic acids, and flavonoids. The multivariate statistical approach based on supervised orthogonal projections to latent structures (OPLS-DA) allowed us to predict the chemical profile of sheep milk samples as a function of the high vs no fresh herbage intake, while the prediction model was not significant when considering both hay and concentrate intake. Among the discriminant markers of the herbage intake, we found five phenolic metabolites (such as hippuric and coumaric acids), together with lutein and cresol (belonging to carotenoids and their metabolites). Additionally, a high discriminant power was outlined for lipid derivatives followed by sugars, amino acids, and peptides. Finally, a pathway analysis revealed that the herbage intake affected mainly five biochemical pathways in milk, namely galactose metabolism, phenylalanine metabolism, alpha-linolenic acid metabolism, linoleic acid metabolism, and aromatic amino acids involved in protein synthesis (namely tyrosine, phenylalanine, and tryptophan).

Reproductive Resumption in Winter and Spring Related to MTNR1A Gene Polymorphisms in Sarda Sheep.

The aim of the present research was to evaluate the association between the SNPs rs430181568 and rs407388227 located in the MTNR1A gene with the reproductive recovery of Sarda sheep in different months of ram introduction in the flock (February, March, April and May). In order to address this research gap, we selected two farms, each of which consisted of approximately 1000 animals; a total of 800 ewes (400 for each farm) were genotyped for the two single nucleotide polymorphisms rs430181568 and rs407388227 located in the exon 2 of the MTNR1A. These SNPs are completely linked; thus, each genotype of rs430181568 corresponded to the same genotype for rs407388227. Among the genotyped animals, 240 individuals were selected and divided into four homogeneous groups (A, B, C and D) of 60 subjects, each group based on age (range 3−6 years old), body condition score (BCS) (range 2.0−4.0) and genotype (20 ewes carrying CC/CC, 20 CT/CT and 20 TT/TT genotype). The dates of the ram introduction in each group were 15 February, 15 March, 15 April and 15 May, respectively. In all groups, the lambing date and the number of lambs born from 150 to 220 days after the ram introduction were recorded. In all the groups, the genotypes CC/CC and CT/CT of the polymorphism (rs430181568 and rs407388227) showed the greatest fertility (the ratio between the number of lambed ewes and the ewes exposed to the rams) (p < 0.01) and the shortest distance between ram introduction to lambing (p < 0.01), compared with the TT/TT genotype. In conclusion, we determined that the polymorphisms rs430181568 and rs407388227 were associated with reproductive recovery, after ram introduction, even in February and March, months subsequent to the photorefractoriness period.

Relationship between inbreeding and milk production traits in two Italian dairy sheep breeds.

The effects of inbreeding in livestock species breeds have been well documented and they have a negative impact on profitability. The objective of this study was to evaluate the levels of inbreeding in Sarda (SAR, n= 785) and Valle del Belice (VdB, n= 473) dairy sheep breeds and their impact on milk production traits. Two inbreeding coefficients (F) were estimated: using pedigree (FPED ), or runs of homozygosity (ROH; FROH ) at different minimum ROH lengths and different ROH classes. After the quality control, 38,779 single nucleotide polymorphisms remained for further analyses. A mixed-linear model was used to evaluate the impact of inbreeding coefficients on production traits within each breed. VdB showed higher inbreeding coefficients compared to SAR, with both breeds showing lower estimates as the minimum ROH length increased. Significant inbreeding depression was found only for milk yield, with a loss of around 7g/day (for SAR) and 9g/day (VdB) for a 1% increase of FROH . The present study confirms how the use of genomic information can be used to manage intra-breed diversity and to calculate the effects of inbreeding on phenotypic traits.

Dairy Sheep Grazing Management and Pasture Botanical Composition Affect Milk Macro and Micro Components: A Methodological Approach to Assess the Main Managerial Factors at Farm Level.

Simple SummaryStudies on the management factors that affect milk components at the farm level are important for understanding how to transfer the results from experimental study. Plant phenological stages and partially fresh herbage intakes affect the lactose and milk fatty acid profile. The botanical composition of the grassland partially affects the milk’s phenol content. A few small relationships between plant phenols and milk colour could be of interest to explain the changes in milk colour parameters.The fatty acid profile, vitamins A and E, cholesterol, antioxidant power colour and the phenols profile of Sarda sheep milk from 11 commercial sheep flocks managed under permanent grassland were investigated. In each farm, the structural and managerial data and milk samples were collected during four periods (sampling dates, SD): January, March, May, and July. Data from the milk composition (fat, protein, casein, lactose, and somatic cell count), 68 fatty acids, 7 phenols, 1 total gallocatechin equivalent, ferric reducing antioxidant power, vitamins A and E, cholesterol, degree of antioxidant protection, and the colour (b *, a * and L *) were analyzed by multivariate factorial analysis using a principal component analysis approach. A proc mixed model for repeated measurement to point out the studied factors affecting significant macro and micro milk composition was also used. Only the first five components were detailed in this paper, with approximately 70% of the explained variance detected. PC1 presented the highest positive loadings for milk lactose, de novo FA synthesis and the BH intermediate, whereas OBCFA had negative loadings values. The PC2, LCFA, UFA, MUFA, vitamins E, and DAP showed positive loadings values, while SFA had a negative value. The PC3 showed a high positive loading for total phenols and non-flavonoids. PC4 presented a high positive loading for the milk macro-composition and negative values for n-3 FAs. The PC5 is characterized by high positive loadings for the a * and L * colour parameters whereas negative loadings were detected for the milk flavonoids content. These preliminary results could help to establish future threshold values for the biomarkers in milk sourced from grazing dairy sheep in natural, permanent pasture-based diets.

Variability of genes involved in lipid metabolism and their effect on milk yield, composition and coagulation traits in Sarda sheep

Variability of genes involved in lipid metabolism and their effect on milk yield, composition and coagulation traits in Sarda sheep

Multivariate and Genome-Wide Analysis of Mid-Infrared Spectra of Non-Coagulating Milk of Sarda Sheep Breed

Milk coagulation ability is crucial for the dairy sheep industry since the whole amount of milk is processed into cheese. Non-coagulating milk (NCM) is defined as milk not forming a curd within the testing time. In sheep milk, it has been reported in literature that up to 20% of milk is NCM. Although the clotting properties of individual milk have been widely studied, little attention has been given to NCM and genomic dissection of this trait. Mid-infrared (MIR) spectra can be exploited both to predict cheese-making aptitude and to discriminate between coagulating milk and NCM. The main goals of this work were (i) to assess the predictivity of MIR spectra for NCM classification and (ii) to conduct a genome-wide association study on coagulation ability. Milk samples from 949 Sarda ewes genotyped and phenotyped for milk coagulation properties (MCPs) served as the training dataset. The validation dataset included 662 ewes. Three classical MCPs were measured: rennet coagulation time (RCT), curd firmness (a30), and curd firming time (k20). Moreover, MIR spectra were acquired and stored in the region between 925.92 and 5,011.54 cm−1. The probability of a sample to be NCM was modeled by step-wise logistic regression on milk spectral information (LR-W), logistic regression on principal component (LR-PC), and canonical discriminant analysis of spectral wave number (DA-W). About 9% of the samples did not coagulate at 30 min. The use of LR-W gave a poorer classification of NCM. The use of LR-PC improved the percentage of correct assignment (45 ± 9%). The DA-W method allows us to reach 75.1 ± 10.3 and 76.5 ± 18.4% of correct assignments of the inner and external validation datasets, respectively. As far as GWA of NCM, 458 SNP associations and 45 candidate genes were detected. The genes retrieved from public databases were mostly linked to mammary gland metabolism, udder health status, and a milk compound also known to affect the ability of milk to coagulate. In particular, the potential involvement of CAPNs deserves further investigation.

Sustainability in the Sardinian sheep sector: A systems perspective, from good practices to policy.

Three million sheep raised on 10 000 active farms operating in traditional and innovative farming systems in Sardinia, Italy, account for 13% of sheep milk production in the European Union (EU). Almost all of the milk delivered is processed to sheep cheese and is destined for world trade. The Sardinian dairy sheep sector also emits approximately 1600 kt CO2 eq/year, approximately 60% of regional livestock greenhouse gas (GHG), prompting the need for regional mitigation plans. The SheepToShip LIFE project (EU-LIFE Climate Change Action 2014-2020) is a regional case study to test emission mitigation strategies. Based on the SheepToShip LIFE findings, this paper presents a systems perspective against the backdrop of the Sustainable Development Goals (SDGs) framework, with the aim of underlining system interlinkages between environmental, societal, and economic objectives. The project included (i) a life cycle thinking approach featuring environmental and socioeconomic traits of 18 sheep farms, (ii) on-farm implementation and demonstration of eco-innovative mitigation techniques indicating the most viable actions to reduce impact, (iii) focus groups discussing beliefs and reactions of the main stakeholders, and (iv) group model building producing a causal loop diagram from a systems thinking approach and exploring insights for regional policy-making that aligns with the SDGs. Causal links connect public interventions and stakeholder interaction (SDG 17) to boost farm eco-innovations (SDGs 9 and 8) and education and farmer training (SDG 4), and they foster efficient production (SDG 12) and high-quality food provisioning (SDG 2). These benefits contribute to climate change mitigation (SDG 13), water quality (SDG 6), and farm ecosystem services (SDG 15). Integr Environ Assess Manag 2022;18:1187-1198. © 2022 SETAC.

Study of the Fatty Acid Profile of Milk in Different Sheep Breeds: Evaluation by Multivariate Factorial Analysis.

Simple SummaryThe quality of milk is strongly influenced by its lipid profile. The increase in fats with nutraceutical properties at the expense of those negative for human health, has always been a goal to improve the functional properties of milk. To achieve this goal, it is essential to know the metabolism of the mammary gland and the relationship between the various lipid components. Much is known about bovine milk, while the aspect relating to the sheep species has not been developed. The present work aims to investigate the relationships between the various fatty acids in sheep’s milk through a multivariate approach, which can highlight the mammary role of lipid synthesis.A multivariate analysis was used to investigate the fatty acid (FA) profile in three different Italian sheep breeds: Comisana, Massese, and Sarda. A sample of 852 animals was considered: 118 Massese, 303 Comisana, 431 Sarda. Sarda sheep were divided into two groups, based on their breeding origin (298 and 133 reared in Sardinia and Tuscany, respectively). Sarda sheep, bred both in Sardinia and in Tuscany, were considered in different groups, both because in these two regions most of the sheep of this breed are reared, and because they differ in geographical characteristics and in the farming system. The individual milk FA composition of dairy ewes was analyzed with multivariate factor analysis. The extracted factors were representative of the following eight groups of fatty acids or functions: factor 1 (odd branched fatty acids and long-chain fatty acids), factor 2 (sn3_position), factor 3 (alternative biohydrogenation), factor 4 (SCD_1), factor 5 (SCD_2), factor 6 (SCD_3), factor 7 (fat secretion) and factor 8 (omega-3). A factor analysis suggested the presence of different metabolic pathways for de novo short- and medium-chain fatty acids and Δ9-desaturase products. The ANOVA of factor scores highlighted the significant effects of the breed. The results of the present study showed that breed is an important factor in defining the fatty acid profile of milk, combined with the effect of the diet. Breeds reared in the same farming system (Comisana, Massese and Sarda reared in Tuscany) showed significant differences for all the factors extracted. At the same time, we found differences between the Sarda sheep reared in Sardinia and Tuscany, two different regions of Italy.

Molecular Typing and Antimicrobial Susceptibility Profiles of Streptococcus uberis Isolated from Sheep Milk.

Intramammary infections are a major problem for dairy sheep farms, and Streptococcus uberis is one of the main etiological agents of ovine mastitis. Surveys on antimicrobial resistance are still limited in sheep and characterization of isolates is important for acquiring information on resistance and for optimizing therapy. In this study, a sampling of 124 S. uberis isolates collected in Sardinia (Italy) from sheep milk was analyzed by multilocus-sequence typing (MLST) and pulsed field gel electrophoresis (PFGE) for genetic relatedness. All isolates were also subjected to antimicrobial susceptibility analysis by the disk diffusion test using a panel of 14 antimicrobials. Resistance genes were detected by PCR assays. MLST analysis revealed that the isolates were grouped into 86 sequence types (STs), of which 73 were new genotypes, indicating a highly diverse population of S. uberis. The most frequently detected lineage was the clonal complex (CC)143, although representing only 13.7% of all characterized isolates. A high level of heterogeneity was also observed among the SmaI PFGE profiles, with 121 unique patterns. Almost all (96.8%) isolates were resistant to at least one antimicrobial, while all exhibited phenotypic susceptibility to oxacillin, amoxicillin-clavulanic acid and ceftiofur. Of the antimicrobials tested, the highest resistance rate was found against streptomycin (93.5%), kanamycin (79.8%) and gentamicin (64.5%), followed by novobiocin (25%) and tetracycline-TE (19.3%). Seventy-four (59.7%) isolates were simultaneously resistant to all aminoglycosides tested. Seventeen isolates (13.7%) exhibited multidrug resistance. All aminoglycosides-resistant isolates were PCR negative for aad-6 and aphA-3′ genes. Among the TE-resistant isolates, the tetM gene was predominant, indicating that the resistance mechanism is mainly mediated by the protection of ribosomes and not through the efflux pump. Three isolates were resistant to erythromycin, and two of them harbored the ermB gene. This is the first study reporting a detailed characterization of the S. uberis strains circulating in Sardinian sheep. Further investigations will be needed to understand the relationships between S. uberis genotypes, mastitis severity, and intra-mammary infection dynamics in the flock, as well as to monitor the evolution of antimicrobial resistance.

Milkability traits across milk flow curve types in Sarda sheep

A temporary interruption of the milk flow is observed between alveolar and cisternal fraction in ewes for the peculiar anatomy of the mammary gland. Often during milking a physiological delay in milk excretion between the cisternal and the alveolar fraction occurs. However, long delays may indicate suboptimal pre-stimulation of teats and/or insufficient oxytocin release in the bloodstream, resulting in undesired protracted interruptions between the 2 milk peaks. Moreover, a clear distinction between the fractions may be undetectable in high-producing ewes, particularly in early lactation. Based on both milk flow curve shape and duration of different excretion phases during milking, 3 curve types can be identified: single-peak (P1), double-peak (P2), and long plateau (PL). The aim of the present study was to compare milkability traits across the 3 milk flow curve types using data recorded in Sarda sheep breed; for this scope, 10 features were measured with a milkmeter in 568 ewes belonging to different parities, lactation stages, and commercial farms. After editing, data of 544 ewes reared in 17 farms were available for the analysis. The P1 curves were the most frequent (57.5 %), but ewes with a PL curve were significantly more productive than those with a P1 curve (0.61 ± 0.03 vs 0.53 ± 0.02 kg of milk/milking). Milk yield of P2 ewes was intermediate (0.58 ± 0.03 kg of milk/milking) and in all curves the majority of milk was excreted in the first 60 s of milking. The highest milk flow rate and the shortest milk emission time were estimated for the P1 curves; moreover, the blind time, indicator of overmilking, was the minimum in PL curves and the maximum in P1 curves. Based on such findings, farmers are recommended to pay more attention to milk emission curves in their herd in order to avoid overmilking, particularly in the presence of P1 curves. Considering the large herd size of Sarda breed farms (170.3 ewes per farm in 2020), part of milking routine could be slightly modified and customized according to milk flow curve type and lactation stage. Ideally, this will allow optimal milking practices to be adopted within groups of ewes with similar milkability. Monitoring milk emission curves and adopting less-standard and more adjusted milking practices is useful to meet the ewe’s individual milking ability and in the long term would limit mammary gland stress, reduce antimicrobial use due to udder issues, and improve the udder health in Sarda sheep.

Novel Genes Associated with Dairy Traits in Sarda Sheep.

Simple SummaryIn a population of 1112 individuals of Sarda sheep, we investigated the polymorphism of 45 single nucleotide polymorphisms (SNPs) in 15 different genes that have been previously investigated because of their relation to metabolism and innate immunity. For SNPs with a sufficient allele frequency, we also tested their influence on a wide panel of dairy traits. The genotyping evidenced some new genetic patterns, and seven SNPs had significant influences on the milk yield, composition and coagulation traits. The results may represent a starting point to acquire new knowledge in the field of dairy sheep sector and to improve the breeding schemes for the Sarda sheep breed.The aim of the present research was to analyze the variability of 45 SNPs from different genes involved in metabolism and innate immunity to perform an association analysis with the milk yield, composition and milk coagulation traits. A population of 1112 Sarda breed sheep was sampled. Genotyping was generated by a TaqMan Open ArrayTM. Thirty out of the 45 SNPs were polymorphic, and 12 displayed a minor allele frequency higher than 0.05. An association analysis showed that the variability at genes PRKAG3 and CD14 was significantly associated with the daily milk yield. The variability at PRKAG3 was also associated with the protein and casein content, somatic cell score and bacterial score. The variation at the PRKAA2 gene was associated with the milk lactose concentration. The SNPs at CD14 were also associated with the traditional milk coagulation properties, while the SNPs at GHR and GHRHR were associated with kSR, a derived coagulation parameter related to the rate of syneresis. The information provided here is new and increases our knowledge of genotype–phenotype interactions in sheep. Our findings might be useful in appropriate breeding schemes to be set up for the Sarda sheep breed, but these should be confirmed by further studies, possibly performed on independent populations.

Effect of Body Condition Score, Treatment Period and Month of the Previous Lambing on the Reproductive Resumption of Melatonin-Treated Sarda Breed Sheep during Spring

Simple SummaryImproving reproductive efficiency in sheep farms is a crucial task for researchers. Therefore, the present research considers the conditions commonly found in Sarda sheep farms and evaluates the effects on reproductive activity via the following factors: exogenous melatonin treatment through subcutaneous implants, different periods of melatonin treatment, varying body condition scores (BCS) and the previous lambing of the treated ewes. The results of the present research suggest that melatonin treatment is able to reliably enhance reproductive efficiency. Furthermore, the findings indicate that optimal reproductive efficiency can be achieved by ensuring that melatonin is administered in April to ewes that have a BCS of >2.5 and have passed their third month of lactation.Stakeholders place great emphasis upon rationalizing the management and rearing techniques which are utilized within sheep farms. The present study aimed to investigate factors which may improve the reproductive performance of melatonin-treated Sardinian sheep via a series of three trials. The first trial (n = 100) investigated the effect of melatonin treatment alongside body condition score (BCS), the second trial (n = 150) investigated the effect of treatment alongside the date of treatment (treatment period) and the third trial (n = 150) investigated the effect of treatment alongside the previous lambing of the ewes. The findings indicated that melatonin is an effective tool for anticipating and improving the reproductive activity of in Sarda breed sheep during the springtime. Furthermore, to obtain optional results, melatonin implantation should be conducted in April, in ewes that have a BCS of >2.5 and that have passed their third month of lactation.

Natural content of animal and plant sterols, alpha-tocopherol and fatty acid profile in sheep milk and cheese from mountain farming

• This work focuses on alpha-tocopherol and sterol profile in sheep milk and cheese. • The cheese manufacturing does not influence the content of sterols (g 100 g −1 of fat). • The cheese making process influences lanosterol and the alpha-tocopherol content. • Phytosterols, which are nutraceutical molecules, were found in the milk and cheese. Milk and dairy foods from grazing animals contain a series of bioactive compounds that are important for human health such as fatty acids, vitamins, and sterols of animal and vegetal origin. To the best of our knowledge, no published studies exist on the phytosterol profile in sheep milk and cheese. In addition, there is little information on the changes in the vitamin E content and sterol profile in sheep milk as a result of the cheese manufacturing and ripening. This study investigates the alpha-tocopherol content, the sterol and fatty acid profile in sheep milk and in two traditional cheeses (Pecorino and Casu Axedu). We also compared the effects of two different commercial manufacturing processes on the trasfer of lipid components in the two cheeses made with the same sheep milk. The study involved a flock of Sardinian sheep in the advanced phase of lactation and grazed on natural mountain pasture. Every 15 days, four bulk milk samples were taken and analyzed. The milk was used to make two traditional cheese: Casu Axedu and Pecorino; cheese samples made from the same batch of analyzed milk were taken. The results of the composition of milk and cheeses (Pecorino and Casu Axedu) were analyzed by ANOVA considering as fixed effect of the product type. The milk alpha-tocopherol content detected was 3.24 mg 100 g −1 of fat, a tendence to decrese in alpha-tocopherol content was highlighted in the cheese fat compared to the milk, probably due to losses of this vitamin during cheese making and seasoning. Cholesterol was the main animal sterol in the milk and cheeses. We found significantly lower cholesterol content (mg 100 g −1 of fat) in cheeses than in milk. In the milk and Casu Axedu, the main minor sterol of animal origin was lanosterol, while in Pecorino lanosterol was less represented. The amount of total plant sterols detected in the milk and dairy products ranged from 9.89 mg 100 g −1 of fat in milk to 16.67 mg 100 g −1 of fat in Pecorino cheese. No significant differences were found in plant sterols among the products (mg 100 g −1 of fat), however a tendence to a higher content of beta-sitosterol was registered in Pecorino cheese on wet basis. Finally, Pecorino was richer in SCFA and PUFA than Casu Axedu, and showed significantly higher contents of some fatty acids of nutritional interest such as C18: 2 cis 9, cis12, C18: 3 omega 3 and CLA cis 9, trans 11. This work contributes to the knowledge of the bioactive components in milk and in the products of small ruminants reared on mountain pasture highlighing, for what we believe is the first time, the presence of minor sterols of vegetable origin in sheep milk and cheese. The cheese making process influences the fatty acid profile and the alpha-tocopherol transfer from milk to cheese, whereas has only few effects on the minor sterols.