Dairy Sheep Research Articles

Impact of truncating historical data on prediction ability of dairy sheep selection candidates

Along the last decades, the genetic evaluation methodology has evolved, improving breeding value estimates. Many breeding programmes have historical phenotypic records and large number of generations, but to make use of them could result in more inconveniences than benefits. In this study, the prediction ability of genotyped young animals was assessed by simultaneously evaluating the removal of historical data, two pedigree deepness and two methodologies (traditional BLUP and single−step genomic BLUP or ssGBLUP), using milk yield records of 40 years of three Latxa dairy sheep populations. The linear regression method was used to compare predictions of young rams before and after progeny testing, with six cut-off points, by intervals of 4 years (from 1992 to 2012), and statistics of ratio of accuracies, bias, and dispersion were calculated. The prediction accuracy of selection candidates, when genomic information was included, was the highest in all Latxa populations (between 0.54 and 0.69 with full data set). Nevertheless, the deletion of historical phenotypic data resulted on moderate accuracy gain in the bigger data size populations (mean gain 2.5%), and the smaller population took advantage of a moderate data deletion (2.7% gain by removing data until 2004), reducing accuracy when more records were removed. The bias of validation individuals was lower when the breeding value was predicted based on genomic information (between 2.1 and 13.9), being lower when the biggest amount of data was deleted in the bigger data size populations (5.2% reduction), and the smaller population was benefited from data deletion between 1996 and 2008 (3.8% bias reduction). Meanwhile, the slope of estimated genetic trend was lower when less data were included, and an overestimation of the unknown parent group estimates was observed. The results indicated that ssGBLUP evaluations were outstanding, compared with traditional BLUP evaluations, while the depth of pedigree had a very small influence, and deletion of historical phenotypic data was beneficial. Thus, Latxa routine genetic evaluations would benefit from truncating phenotypic records between 2000 and 2004, the use of two pedigree generations and the implementation of ssGBLUP methodology.

The dark side of the wool? From wool wastes to keratin microfilaments through the solution blow spinning process

The valorization of discarded wool from dairy sheep breeding is a challenging issue. The most proposed strategies lie in the processing of keratin extracted from wool without reducing the molecular weight of the protein chains (the high molecular weight-HMW keratin). Here, the HMW keratin has been spun for the first time by solution blow spinning. A screening study of the process carried out with a 2-level full factorial design revealed that keratin filaments can be obtained by using the polyethylene oxide at 900 kDa, a 2 bar air pressure, and a 30 cm needle-collector distance. An annealing at 80 °C for 15 min, at pH 3.5 with citric acid contributes to increasing the viscosity of the keratin solutions thereby allowing the production of defect-free and water-stable filaments having diameters from 1 to 6 μm. A negligible toxic effect was observed after 24 and 48 h on HT29 epithelial cells and normal blood cells displayed behavior similar to the control demonstrating that the patches are hemocompatible. Therefore, the developed SBS process of keratin aqueous solutions could represent a valuable platform for developing patches that need to be blood-contacting and deposited in-situ.

Estimation of genetic parameters for production, composition and processability of milk from dairy sheep in a New Zealand flock

ABSTRACT This paper aimed to estimate the heritability and genetic correlations for processability (milk coagulation properties, cheese yield, and heat stability), milk production, and milk composition of dairy sheep in a New Zealand flock. Test-day records from 169 ewes were obtained during the 2021–2022 season. Heritability estimates for yield traits (milk, fat, protein, and lactose yield) were moderate and ranged from 0.33 to 0.38. Whereas heritability estimates for processability traits were lower and ranged from 0.17 to 0.27. The genetic correlations indicated that poorer milk coagulation properties were associated with lower mammary health indicated by higher SCS, higher pH, and lower lactose content. Additionally, a higher ratio of casein to calcium i.e. lower availability of soluble calcium was associated with poorer milk coagulation properties. Higher yields of milk, fat, protein, and lactose were associated, but to a smaller degree, with better MCP. It is proposed that genetic improvement of dairy sheep for higher yields of fat and protein, and for lower SCS, could indirectly improve milk processability for cheese-making. However, it is recommended that larger studies involving more dairy sheep flocks are conducted to validate the present results before developing a selection index for this industry.

Safety and efficacy of a feed additive consisting of an essential oil obtained from the fruit of Carum carvi L. (caraway oil) for all animal species (FEFANA asbl).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of an essential oil obtained from the fruit of Carum carvi L. (caraway oil), when used as a sensory additive in feed and water for drinking for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) Panel concluded that the use of caraway oil is of no concern up to the following concentrations in complete feed: 9 mg/kg for chickens for fattening, 13 mg/kg for laying hens, 12 mg/kg for turkeys for fattening, 16 mg/kg for piglets, 19 mg/kg for pigs for fattening, 24 mg/kg for sows, 35 mg/kg for veal calves (milk replacer), 11 mg/kg for cattle for fattening, 10 mg/kg for dairy cows, sheep, goats, horses and rabbits, 25 mg/kg for salmonids and dogs. These conclusions were extrapolated to other physiologically related species. For cats, ornamental fish and other species, no conclusion can be drawn. The use of caraway oil in animal feed under the proposed conditions of use is safe for the consumer and the environment. The additive under assessment should be considered as an irritant to skin and eyes, and as a respiratory and skin sensitiser. When handling the essential oil, exposure of unprotected users to perillaldehyde may occur. Therefore, to reduce the risk, the exposure of the users should be minimised. Since C. carvi and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Profiling several key milk miRNAs and analysing their signalling pathways in dairy sheep breeds during peak and late lactation.

The comprehensive understanding of microRNAs (miRNAs) in sheep milk during various lactation periods and their impact on milk yield and composition remains limited. This study aimed to investigate the expression patterns of four highly expressed miRNAs in sheep milk and their association with milk composition and yield parameters during peak and late lactation stages. A total of 40 healthy 4-year-old Akkaraman (n = 20) and Awassi (n = 20) ewes registered with the Ministry of Agriculture and Forestry of the Republic of Türkiye were used in the present study. For miRNA isolation from milk, the Qiagen miRNeasy Serum/Plasma Advanced Kit was utilised following the manufacturer's instructions. The expression levels of miRNAs were assessed using Qiagen miRNA PCR Assays. The significant fold changes in the expression levels of oar-miR-30a-5p, oar-miR-148a and oar-miR-181a were observed between peak and late lactation periods in the Awassi sheep breed. Conversely, only oar-miR-30a-5p and oar-miR-148a exhibited statistically significant changes in the Akkaraman sheep breed during the same lactation periods. Furthermore, oar-miR-21-5p demonstrated a significant fold change exclusively in peak lactation compared to Akkaraman and Awassi ewes. The findings suggest that the expression of the analysed miRNAs is influenced by both the lactation stage and different sheep breeds. This study offers valuable insights into the relationship between key miRNA expressions in sheep milk and milk composition and yield parameters during peak and late lactation, contributing to the existing knowledge in this field.

A single base pair duplication in the SLC33A1 gene is associated with fetal losses and neonatal lethality in Manech Tête Rousse dairy sheep.

We recently discovered that the Manech Tête Rousse (MTR) deficient homozygous haplotype 2 (MTRDHH2) probably carries a recessive lethal mutation in sheep. In this study, we fine-mapped this region through whole-genome sequencing of five MTRDHH2 heterozygous carriers and 95 non-carriers from various ovine breeds. We identified a single base pair duplication within the SLC33A1 gene, leading to a frameshift mutation and a premature stop codon (p.Arg246Alafs*3). SLC33A1 encodes a transmembrane transporter of acetyl-coenzyme A that is crucial for cellular metabolism. To investigate the lethality of this mutation in homozygous MTR sheep, we performed at-risk matings using artificial insemination (AI) between heterozygous SLC33A1 variant carriers (SLC33A1_dupG). Pregnancy was confirmed 15 days post-AI using a blood test measuring interferon Tau-stimulated MX1 gene expression. Ultrasonography between 45 and 60 days post-AI revealed a 12% reduction in AI success compared with safe matings, indicating embryonic/fetal loss. This was supported by the MX1 differential expression test suggesting fetal losses between 15 and 60 days of gestation. We also observed a 34.7% pre-weaning mortality rate in 49 lambs born from at-risk matings. Homozygous SLC33A1_dupG lambs accounted for 47% of this mortality, with deaths occurring mostly within the first 5 days without visible clinical signs. Therefore, appropriate management of SLC33A1_dupG with an allele frequency of 0.04 in the MTR selection scheme would help increase overall fertility and lamb survival.

Thermal Imaging and Dimensionality Reduction Techniques for Subclinical Mastitis Detection in Dairy Sheep

Subclinical mastitis is a common and economically significant disease that affects dairy sheep production. Thermal imaging presents a promising avenue for non-invasive detection, but existing methodologies often rely on simplistic temperature differentials, potentially leading to inaccurate assessments. This study proposes an advanced algorithmic approach integrating thermal imaging processing with statistical texture analysis and t-distributed stochastic neighbor embedding (t-SNE). Our method achieves a high classification accuracy of 84% using the support vector machines (SVM) algorithm. Furthermore, we introduce another commonly employed evaluation metric, correlating thermal images with commercial California mastitis test (CMT) results after establishing threshold conditions on statistical features, yielding a sensitivity (the true positive rate) of 80% and a specificity (the true negative rate) of 92.5%. The evaluation metrics underscore the efficacy of our approach in detecting subclinical mastitis in dairy sheep, offering a robust tool for improved management practices.

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.

Effect of the Replacement of Wheat Straw by Spent Mushroom Substrate in the Diet of Dairy Ewes during Late Lactation on Milk Production, Composition, Oxidation Stability and Udder Health

The aim of the present study was to investigate the effects of different dietary levels of spent mushroom substrate (SMS) at the expense of wheat straw (WS) on milk characteristics in dairy sheep. Thirty ewes at their final stage of lactation (145 ± 5 days after parturition) were randomly assigned into three groups; control (C), provided with a diet consisting of concentrates, alfalfa hay and WS, and SMS1 and SMS2, where WS was replaced by SMS at 50 or 100%, respectively. The experiment lasted for 28 days, and milk yield, composition, somatic cell count (SCC) and oxidative stability were monitored weekly, while milk fatty acid and immune cell profile were also determined on day 28. No significant differences were found in produced milk quantity, fat, protein, lactose, total solids non-fat, SCC and fatty acid profile between the experimental groups. However, milk oxidative stability was significantly improved as an effect of SMS (p < 0.001). At the same time, milk polymorphonuclear leukocyte percentage was decreased in SMS2 group (p < 0.05). As indicated, SMS seems to be a promising agro-industrial by-product for ewes’ diet that could improve milk oxidative stability, without negatively affecting milk yield, composition and ewe health status, contributing in the context of sustainability, circular economy and protection of natural resources.

Biotransformation of Cynomorium flavan-3-ols in dairy sheep and their effects on inflammation and liver growth retardation.

The stems of Cynomorium songaricum are used in traditional Chinese medicine as a tonic and also used locally as a food material and livestock feed. It is known that some of the falvan-3-ol monomers and dimers that entered the milk of dairy sheep fed with C. songaricum stems are biotransformation products of the original flavan-3-ol polymers in C. songaricum stems. This study was performed to investigate the biotransformation process of the flavan-3-ols in dairy sheep and to evaluate the bioactivities. The results showed that procyanidin A2 and epicatechin could be released from the polymeric flavan-3-ols of C. songaricum through rumen microbial metabolism. On traumatic and lipopolysaccharide (LPS)-induced inflammation models of Tg (mpx: EGFP) zebrafish larvae and LPS-induced liver injury models of Tg (fabp10a: DsRed) zebrafish larvae, the milk from sheep fed with C. songaricum stems showed stronger anti-inflammatory and hepatoprotective activities compared to blank milk. The absorbed chemical constituents of C. songaricum stems and the metabolites also exhibited anti-inflammatory and hepatoprotective activities, with the dimeric flavan-3-ols being more effective than the monomers. The milk, the absorbed chemical constituents of C. songaricum stems, and the metabolites alleviated the increased level of reactive oxygen species induced by LPS in zebrafish larvae. PRACTICAL APPLICATION: This study found that C. songaricum stems as livestock feed could produce milk that has a beneficial impact on consumer and livestock health in terms of anti-inflammation and hepatoprotection.

Epidemiological, Virulence, and Antibiotic Resistance Analysis of Klebsiella pneumoniae, a Major Source of Threat to Livestock and Poultry in Some Regions of Xinjiang, China.

Klebsiella pneumoniae (K. pneumoniae) is recognized as a zoonotic pathogen with an increasing threat to livestock and poultry. However, research on K. pneumoniae of animal origin remains limited. To address the gap, a comprehensive investigation was carried out by collecting a total of 311 samples from the farms of four animal species (dairy cow, chicken, sheep, and pig) in selected areas of Xinjiang, China. Isolates were identified by khe gene amplification and 16S rRNA gene sequencing. Genotyping of K. pneumonia isolates was performed using wzi typing and multilocus sequence typing (MLST). PCR was employed to identify virulence and resistance genes. An antibiotic susceptibility test was conducted using the Kirby-Bauer method. The findings revealed an isolation of 62 K. pneumoniae strains, with an average isolation rate of 19.94%, with the highest proportion originating from cattle sources (33.33%). Over 85.00% of these isolates harbored six virulence genes (wabG, uge, fimH, markD, entB, and ureA); while more than 75.00% of isolates possessed four resistance genes (blaTEM, blaSHV, oqxA, and gyrA). All isolates exhibited complete resistance to ampicillin and demonstrated substantial resistance to sulfisoxazole, amoxicillin/clavulanic acid, and enrofloxacin, with an antibiotic resistance rate of more than 50%. Furthermore, 48.39% (30/62) of isolates were classified as multidrug-resistant (MDR) strains, with a significantly higher isolation rate observed in the swine farms (66.67%) compared to other farms. Genetic characterization revealed the classification of the 62 isolates into 30 distinct wzi allele types or 35 different sequence types (STs). Notably, we identified K. pneumoniae strains of dairy and swine origin belonging to the same ST42 and wzi33-KL64 types, as well as strains of dairy and chicken origin belonging to the same wzi31-KL31-K31 type. These findings emphasize the widespread occurrence of drug-resistant K. pneumoniae across diverse animal sources in Xinjiang, underscoring the high prevalence of multidrug resistance. Additionally, our results suggest the potential for animal-to-animal transmission of K. pneumoniae and there was a correlation between virulence genes and antibiotic resistance genes. Moreover, the current study provides valuable data on the prevalence, antibiotic resistance, and genetic diversity of K. pneumoniae originating from diverse animal sources in Xinjiang, China.

An observational study of farmer-reported clinical mastitis in New Zealand dairy ewes

ABSTRACT Aims To describe the incidence, aetiology, treatment, and outcomes of farmer-reported clinical mastitis on New Zealand dairy sheep farms. Methods A prospective cohort study was conducted on 20 spring-lambing New Zealand sheep milking farms over the 2022–2023 season. Clinical mastitis was defined as a change in the appearance of milk and/or signs of inflammation in the gland. Farmers were required to report all cases of clinical mastitis and collect information on affected ewes’ demographics, clinical features, treatments (where applicable), and outcomes. Milk samples from mastitic glands were submitted for microbiological culture and identification by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF). Results Partial or complete clinical mastitis data were available for 236 cases from 221 ewes on 18/20 study farms. Clinical mastitis was diagnosed in 0–6% of ewes at the farm level, with an overall incidence of 1.8 (95% CI = 1.0–3.2)% using the study data, or 2.3 (95% CI = 1.6–3.3)% using the study data and farmer estimates that included unreported cases. Cases occurred mostly in early lactation, with 59% detected during the lambing period (August–October), at a median of 7 (IQR 3, 40) days in milk. The majority of cases featured clots in the milk (59%), swelling (55%), and unevenness (71%) of the glands. Pyrexia (rectal temperature ≥ 40.0°C) was diagnosed in 25% of cases and depression (lethargy, inappetence, or inability to stand) in 26% of cases. Treatment was given to 46% of cases, with tylosin being the most commonly used treatment (50% of treated cases). The most common outcome was immediate drying off to be culled without treatment (32%), followed by still milking and recovered but with lasting problems (25%). Nearly half of all the milk samples submitted were culture negative. Streptococcus uberis (14%), non-aureus staphylococci (12%), and Staphylococcus aureus (11%) were the most common isolates, found on 12, 8 and 8 of the 16 farms with microbiological data, respectively. Conclusions Clinical mastitis affected up to 6% of ewes at the farm level. Systemic signs were observed in one quarter of affected ewes, suggesting a role for supportive treatment. Clinical mastitis can be severe and challenging to fully resolve in New Zealand dairy sheep. Clinical relevance This is the first systematic study of clinical mastitis in New Zealand dairy ewes. It provides baseline information specific to New Zealand conditions for farmers, veterinarians, and other advisors to guide the management of mastitis for the relatively new dairy sheep industry in New Zealand.

Risk Categorization in On-Farm Welfare in Different-Sized Dairy Sheep Flocks.

The objective of the present work was to categorize the risks in the on-farm welfare of dairy sheep in semi-extensive systems in order to highlight if risks in welfare vary according to the farm size. To the best of our knowledge, this study constitutes one of the few categorizations of the risks in the welfare of dairy sheep reared semi-extensively. The survey was conducted on 12 semi-extensive dairy sheep farms in Tuscany (Central Italy), which were classified according to flock size: <500, from 500 to 1000, and >1000. The results showed an adequate rating for all the farms included in the study. The most critical issues concerned the ratio between the number of stockpersons and the number of animals within the farms, the small decubitus areas, the lack of udder cleaning procedures during milking operations, and, in terms of biosecurity, the lack of prevention, control, and eradication plans for the most important infectious ovine diseases. The results show that different items in the five areas evaluated, including the assessments of management of the flock, the number of daily inspections, and the hygiene of the water supplies are associated with the farm size. In large farms, the assessment of management of the flock was better, but the number of daily inspections and the hygiene of the water supplies were worse.

Cocoa byproduct inclusion in dairy sheep diet: Effects on sensory, volatile, and antioxidant properties of cheese

The possibility of inclusion of agro-industrial byproducts in the diet of small ruminants represents both an economic and an environmental strategy for reducing waste management by industries and costs of feeding as well as the impact of livestock farming. Large amounts of wastes from the cocoa industry are produced annually, with a considerable part represented by cocoa bean shells, considered a suitable ingredient to be included in the diet of ruminants within the limits established by European legislation. The aim of this study was to assess the effect of including cocoa bean shells in the diet of dairy sheep on the sensory, volatile, and antioxidant properties of cheese. To this purpose, 20 lactating Comisana ewes were randomly assigned to 2 experimental groups: control (CTRL) and cocoa bean shells (CBS), and received alfalfa hay ad libitum and 800 g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Bulk milk collected from each group was used to produce a total of 15 cheeses per group, obtained in 5 different days of cheesemaking (3 cheeses a day per group). After 60 d of aging, each cheese of each experimental group was sampled for the analyses. The results on chemical composition revealed a greater content of monounsaturated fatty acids and an increase in the nutritional indices, suggesting a favorable role of cocoa bean shell dietary inclusion on the nutritive value of cheese. The cheese sensory profile was affected by the cocoa bean shell inclusion, with more pronounced appearance, odor, aroma, and taste attributes in the product. The volatile profile showed only a few significant differences, mainly related to the cheese ripening process, and no differences were found in α-tocopherol contents in cheese fat between the 2 groups. Therefore, the inclusion of coca bean shells in the diet of dairy sheep allowed us to obtain a good-quality cheese, without altering the characteristics associated with the typical profiles of sheep cheese. Furthermore, the use of this byproduct could contribute to decreasing feed costs and waste management, representing a good practice for increasing the sustainability of dairy products.

Assessing the impact of climate action mitigation strategies from livestock production: A review – Solution for greenhouse gases mitigation

Abstract The main sources of greenhouse gas (GHG) emissions are enteric fermentation from ruminants and manure management. An integrated strategy-combination approach incorporating nutrition and manure management is necessary to dramatically reduce GHGs and the carbon footprint of milk production. The aim of this review was to assess the effect of climate action mitigation strategies on the GHG production of ruminant animals. This review was based on the different references, which are textbooks, journals, proceedings, conferences, and abstracts accessed through Agricola, Agris, CAB Abstracts, Embase, MEDLINE, and the Web of Science. The research findings were done by using dairy cattle, sheep, and goat; the numbers of animals used in each experiment were given the majority of attention, and decisions were also made based on the method used to quantify methane (CH 4 ) and nitrous oxide. Enteric CH 4 per unit of milk was reduced by 6–8% when higher-starch corn silage was used in place of barley or alfalfa silage. Cows fed seaweed (1.77–2%, on dry matter [DM] basis) experienced a linear drop in enteric CH 4 emission from 383 to 400 g/d. Supplementation of vegetable fats (6%) and coconut oil (12 g/day) to ruminant diets can decrease CH 4 emissions by 21–40% and 50–61.2%, respectively. Similarly, the addition of 21.5 g nitrate/kg DM reduces CH 4 yield (17%) in sheep. Bovaer can reduce methane emissions (30%) for dairy cows. Feed processing and additives are alternative strategies to minimize GHG production in ruminants, but further studies on additives and their residual effect on livestock output is needed.

Efficacy of the feed additive consisting of Saccharomyces cerevisiaeCNCM I-4407 (Actisaf® Sc47) for cattle for fattening (Lesaffre International).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the efficacy of Saccharomyces cerevisiae CNCM I-4407 (Actisaf® Sc47) as a zootechnical feed additive (functional group: gut flora stabiliser) in cattle for fattening. The additive is already authorised for use in feed for dairy cows, calves for rearing, lambs for fattening, dairy goats, dairy sheep and dairy buffaloes. In a previous opinion, the EFSA Scientific Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) concluded that Actisaf® Sc47 was safe for cattle for fattening, the consumers and the environment. Additionally, the Panel considered that Actisaf® Sc47 is not a skin irritant, and no conclusions could be drawn on the additive's eye irritancy and dermal sensitisation potential. Due to the lack of adequate data, the Panel could not conclude on the efficacy of the additive in cattle for fattening at the proposed conditions of use. In the current application, the applicant submitted three trials to support the efficacy in cattle for fattening. However, two of them were not considered for the assessment. The other trial showed an improved zootechnical performance of the animals at the proposed use level of 4 × 109 CFU/kg complete feed. Considering the additive is authorised in dairy cows and calves for rearing and the requirements of the current Guidance on the assessment of the efficacy of feed additives, no further demonstration of efficacy is necessary to extrapolate the conclusions previously reached to all ruminants. The significant positive effect shown in one trial in cattle for fattening supports the above extrapolation. Therefore, the FEEDAP Panel concludes that Actisaf® Sc47 is efficacious as a zootechnical additive for cattle for fattening at the proposed conditions of use.

Genetic Characterization of Small Ruminant Lentiviruses Isolated from Dairy Sheep in Greece.

The high genetic heterogeneity of small ruminant lentiviruses (SRLV) renders the genetic characterization of the circulating strains crucial for the epidemiological investigation and the designation of effective diagnostic tools. In Greece, research data regarding the genetic diversity of the circulating SRLV strains is scarce, hindering the implementation of efficient surveillance and control programs. The objective of the study was to genetically characterize SRLV strains isolated from intensive dairy sheep farms in Greece and evaluate the variability of the immunodominant regions of the capsid protein. For this reason, a total of 12 SRLV-infected animals from four intensive dairy sheep farms with purebred Chios and Lacaune ewes were used for the amplification and sequencing of an 800 bp gag-pol fragment. The phylogenetic analyses revealed a breed-related circulation of strains; Chios ewes were infected with strains belonging exclusively to a separate group of genotype A, whereas strains belonging to subtype B2 were isolated from Lacaune ewes. Immunodominant epitopes of capsid protein were quite conserved among the strains of the same genotype, except for the Major Homology Region which showed some unique mutations with potential effects on viral evolution. The present study contributes to the extension of the current knowledge regarding the genetic diversity of SRLV strains circulating in sheep in Greece. However, broader genetic characterization studies are warranted for the exploration of possible recombinant events and the more comprehensive classification of the circulating strains.

Animal factors affecting the cheese-making properties and the heat coagulation time of milk from dairy sheep in a New Zealand flock

ABSTRACT The objective of this study was to evaluate the effect of animal factors on the cheese-making properties and on the heat coagulation time of milk from individual dairy sheep in a New Zealand flock. A total of 521 individual records were obtained from a seasonal pasture-based flock of 169 ewes milked once-a-day, from 50 to 182 days in milk. A statistical model was used to quantify the effects of animal factors (coat colour variety, age, litter size and stage of lactation) on the studied traits. Stage of lactation, confounded with seasonality, strongly influenced all properties of milk investigated. With the advancement of lactation, the milk took longer to coagulate after rennet addition, and the curd was softer. Higher relative cheese yield was achieved towards the end of lactation. The milk was also less stable to high-temperature treatment in late lactation. Coefficient of variation for processability traits was high and ranged from 20.2% to 58%, which can be largely attributed to stage of lactation but could also indicate room for genetic improvement of traits. Further genetic studies are underway to define animal genetic variance, heritability, and the phenotypic and genetic correlations between these processability and milk composition traits.

Identification and bioactivity evaluation of ring-opening and lactone forms of enterolactone from sheep fed flaxseed cake

The previously undescribed lactone ring-opening enterolactone and its sulphate were purified along with the lactone counterparts from the urine of dairy sheep fed flaxseed cake. The structures were determined by NMR and MS analyses. The ring-opening and lactone forms underwent mutual transformation with changes in pH and milk could protect the lactone form. Enterolactone exhibited more effective anti-proliferation activity on MDA-MB-231 breast cancer cells than its ring-opening counterpart, while the ring-opening enterolactone demonstrated more effective anti-osteoporosis activity than the lactone form. The results indicated the potential for targeting biological functions through pH and medium manipulation.

Exploring Breed-Specific Milk Coagulation in Spanish Dairy Sheep: A Canonical Correlation Approach.

The transformation of milk into cheese largely depends on the technological properties of the raw material, with breed being a crucial factor that influences both the composition and coagulation properties of the milk used for cheesemaking. This study uses canonical correlation analysis to explore the relationships between physicochemical traits and coagulation properties in milk from various Spanish breeds, aiming to identify both common and breed-specific patterns that impact milk technological aptitude. A total of 832 milk samples from Manchega, Assaf, Merino de Grazalema, and Merino de Los Pedroches breeds were analyzed. The milk characteristics investigated included pH, composition (fat, protein, lactose, total solids), and coagulation properties (curd firmness-A60, rennet clotting time-RCT, curd firming time-k20, and individual laboratory curd yield-ILCY). The results reveal a shared correlation structure across breeds and unique covariation patterns in some breeds that deviate from the general trend. While Assaf and Merino de Los Pedroches follow the common correlation pattern, Manchega and Merino de Grazalema exhibit distinct patterns. This research underscores the need for in-depth study and suggests that the dairy industry could benefit from shifting from the traditional focus on maximizing fat and protein for higher curd yields to considering technological traits for selective breeding.