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At the global level, the quantity of goat milk produced and its gross production value have increased considerably over the last 2 decades. Although many scientific papers on this topic have been published, few studies have been carried out on bulk goat milk samples. The aim of the present study was to investigate in the field the effects of farming system, breed type, individual flock, and stage of production on the composition, coagulation properties (MCP), curd firming over time parameters (CF

The aim of the present study was to evaluate variability and haplotype structure of twenty-eight single nucleotide polymorphisms (SNPs) at myostatin (MSTN), insulin-like growth factor 1 (IGF1), and bone morphogenetic protein 2 (BMP2) genes. Association between the polymorphic SNPs and morphometric traits was performed on a population of 263 Tunisian goats. The SNPs analyzed were all polymorphic (except one), and the three genes had different haplotype structures. Significant association of SNPs at MSTN with head length was highlighted in the Tunisian goats. The variability at IGF1 gene was associated with body length, ear length, tail length, and chest depth. For BMP2, significant association was revealed with chest depth. Significant association was also detected between linkage disequilibrium (LD) block 2 at IGF1 with body length. These findings might play a potential role in gene-assisted programs.

Milk lactose, pH, somatic cell count (SCC), bacterial count and NaCl are indirect markers of the mammary gland status; they can be used to screen milk quality and its technological properties. The variability of milk composition and coagulation properties from 1272 individual goat milk samples as a function of the udder health indicators was investigated. High lactose concentrations were associated with reduced coagulation time, but weakened curd firmness traits. High pH values impaired coagulation, while high SCC had delayed coagulation time but reduced curd-firming rate. Samples with high bacterial count were characterised by softer curds, but had faster curd-firming and larger syneresis rates. High concentrations of NaCl were associated with reduced fat, protein, and casein content, and impaired coagulation traits. These results show that the concurrent analysis of these markers can be highly informative and suitable to monitor the quality of milk destined for cheese-making.

We investigated whether variation of the sheep Growth Hormone Receptor (GHR), Growth Hormone Releasing Hormone Receptor (GHRHR) and Insulin-Like Growth Factor 1 (IGF1) genes were associated with milk coagulation properties (MCP) in sheep. The GHR, GHRHR and IGF1 genes are part of the GH system, which is known to modulate metabolism, growth and reproduction as well as mammogenesis and galactopoiesis in dairy species. A total of 380 dairy Sarda sheep were genotyped for 36 SNPs mapping to these three genes. Traditional MCP were measured as rennet coagulation time (RCT), curd-firming time (k20) and curd firmness at 30 m (a30). Modeling of curd firming over time (CFt) was based on a 60 m lactodynamographic test, generating a total of 240 records of curd firmness (mm) for each milk sample. The model parameters obtained included: the rennet coagulation time as a result of modeling all data available (RCTeq, min); the asymptotic potential value of curd firmness (CFP, mm) at an infinite time; the CF instant rate constant (kCF, %/min); the syneresis instant rate constant (kSR, %/min); the maximum value of CF (CFmax, mm) and the time at achievement of CFmax (tmax, min). Statistical analysis revealed that variation of the GHR gene was significantly associated with RCT, kSR and CFP (P < 0.05). No other significant associations were detected. These findings may be useful for the dairy industry, as well as for selection programs.

Milk traits and coagulation properties (MCP) were investigated in a population of 960 Sarda ewes distributed in 21 farms, in order to propose a limit of somatic cells (SCC) by using the statistical analysis of milk traits and MCP from a large population of ewes. At each farm, from 20 to 80 ewes were individually sampled (one sampling day for each farm), during the afternoon milking. Ewes were between two and seven months after parturition, and the first and seventh parity. Daily milk yield was recorded on the same day of sampling. Milk samples were analyzed to achieve traits of milk composition (fat, protein, casein, lactose, and pH), total bacterial count (TBC), SCC, traditional MCP (rennet coagulation time: RCT; curd-firming time: k20; curd firmness after 30, 45 or 60 min from rennet addition: respectively a30, a45 and a60) and model parameters of curd-firming (curd firmness at an infinite time: CFP; curd firming instant rate constant: kCF; RCT estimated from the equation: RCTeq; syneresis instant rate constant: kSR; maximum curd firmness: CFmax; and attainment time of the maximum curd firmness: tmax). TBC and SCC were log transformed in their respective scores LBC and SCS. The Pearson product moment correlation coefficient was used to investigate the supposed linear relationship between LBC and SCS and a regression analysis to obtain the plots, model and the values of SCS predicted by using LBC. Results evidenced a positive correlation between SCS and LBC. Despite the very low R2 from the regression analysis, two putative cut-off limit of SCC were calculated: 180,000 SCC/mL, corresponding to 500,000 TBC/mL, and 545,000 SCC/mL, corresponding to 1,500,000 TBC/mL. Later, three groups of SCC-related milk samples were obtained: Low-SCC group (L-SCC), with samples showing a SCC lower than the estimated limit of 180,000/mL; High-SCC group (H-SCC), samples with SCC higher than 545,000/mL; Intermediate-SCC group (I-SCC), samples showing a SCC between the two limits of L-SCC and H-SCC. The L-SCC group showed the highest daily milk yield and lactose content, and the lowest values of fat, protein and casein content and pH. H-SCC group showed delayed coagulation times (both RCT and RCTeq), k20, tmax and kCF. In conclusion, milk yield and coagulation properties registered significant worsening in those milk samples with SCC higher than 545,000 SCC/mL. This value could be the starting point for the improvement of milk traits and coagulation properties from the Sarda sheep.

Simple Summary In 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. Abstract 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.

One hundred and eighty Anglo-Arabian horses running 1239 races were sampled for the present study. DNA was extracted from the blood and myostatin gene, MSTN, was genotyped. Moreover, prizes won and places were achieved for the 1239 races to perform association analyses between the different genotypes and sport traits. Two SNPs already reported in previous studies regarding the Thoroughbred breed, rs69472472 and rs397152648, were revealed as polymorphic. The linkage disequilibrium analysis investigating the haplotype structure of MSTN did not evidence any association block. Polymorphism at SNP rs397152648, previously known as g.66493737 T&gt, C, significantly influenced sport traits, with heterozygous horses TC showing better results than homozygotes TT. The portion of variance due to the random effect of the individual animal, and the other phenotypic effects of sex, percentage of Arabian blood and race distance, computed together with the genotype at MSTN in the statistical models, exerted a significant influence. Hence, this information is useful to improve knowledge of the genetic profile of Anglo-Arabian horses and a possible selection for better sport performance.

Sahraoui H, Madani T, Fantazi K, Chaouch Khouane A, Ameur Ameur A, Paschino P, Vacca GM, Gaouar SBS, Dettori ML. 2020. Genetic variability in the A microsatellite at SLC11A1 gene and possible implications with innate resistance against brucellosis in Algerian native goats. Biodiversitas 21: 5630-5636. Goat rearing is among the major agricultural activities practiced in Algeria. However, brucellosis represents an important threat to the goat sector and to public health. The aim of our work was to characterize the genetic variability of the A microsatellite at the 3' untranslated region (3' UTR) of SLC11A1 gene in Algerian native goat breeds as it was associated with Brucellosis genetic resistance in goat. Genomic DNA samples of 90 goats belonging to the four Algerian native breeds; Mekatia (n = 32), Arbia (n = 30), Dwarf of Kabylia (n = 14) and Mozabit (n = 14) have been analyzed. Polymorphism of region A microsatellite was determined by capillary electrophoresis identifying 8 alleles and 20 genotypes. Genetic parameters were also estimated. Polymorphic information content was PIC = 0.60, the observed and the expected heterozygosity were Ho = 0.569 and He = 0.595, respectively, and the values of FIS, FIT and FST were 0.044, 0.064, and 0.021, respectively. The A microsatellite was highly polymorphic and alleles associated genetic resistance against brucellosis in other breeds or species have been identified. These results open a promising opportunity to implement a genetic improvement program to reduce goat brucellosis spread in Algeria.

Driven by the large amount of goat milk destined for cheese production, and to pioneer the goat cheese industry, the objective of this study was to assess the effect of farm in predicting goat milk-coagulation and curd-firmness traits via Fourier-transform infrared spectroscopy. Spectra from 452 Sarda goats belonging to 14 farms in central and southeast Sardinia (Italy) were collected. A Bayesian linear regression model was used, estimating all spectral wavelengths' effects simultaneously. Three traditional milk-coagulation properties [rennet coagulation time (min), time to curd firmness of 20 mm (min), and curd firmness 30 min after rennet addition (mm)] and 3 curd-firmness measures modeled over time [rennet coagulation time estimated according to curd firmness change over time (RCTeq), instant curd-firming rate constant, and asymptotical curd firmness] were considered. A stratified cross validation (SCV) was assigned, evaluating each farm separately (validation set; VAL) and keeping the remaining farms to train (calibration set) the statistical model. Moreover, a SCV, where 20% of the goats randomly taken (10 replicates per farm) from the VAL farm entered the calibration set, was also considered (SCV80). To assess model performance, coefficient of determination (R2VAL) and the root mean squared error of validation were recorded. The R2VAL varied between 0.14 and 0.45 (instant curd-firming rate constant and RCTeq, respectively), albeit the standard deviation was approximating half of the mean for all the traits. Although average results of the 2 SCV procedures were similar, in SCV80, the maximum R2VAL increased at about 15% across traits, with the highest observed for time to curd firmness of 20 mm (20%) and the lowest for RCTeq (6%). Further investigation evidenced important variability among farms, with R2VAL for some of them being close to 0. Our work outlined the importance of considering the effect of farm when developing Fourier-transform infrared spectroscopy prediction equations for coagulation and curd-firmness traits in goats.

The prediction of traditional goat milk coagulation properties (MCP) and curd firmness over time (CFt) parameters via Fourier-transform infrared (FTIR) spectroscopy can be of significant economic interest to the dairy industry and can contribute to the breeding objectives for the genetic improvement of dairy goat breeds. Therefore, the aims of this study were to (1) explore the variability of milk FTIR spectra from 4 goat breeds (Camosciata delle Alpi, Murciano-Granadina, Maltese, and Sarda), and to assess the possible discriminant power of milk FTIR spectra among breeds, (2) assess the viability to predict coagulation traits by using milk FTIR spectra, and (3) quantify the effect of the breed on the prediction accuracy of MCP and CFt parameters. In total, 611 individual goat milk samples were used. Analysis of variance of measured MCP and CFt parameters was carried out using a mixed model including the farm and pendulum as random factors, and breed, parity, and days in milk as fixed factors. Milk spectra for each goat were collected over the spectral range from wavenumber 5,011 to 925 × cm-1. Discriminant analysis of principal components was used to assess the ability of FTIR spectra to identify breed of origin. A Bayesian model was used to calibrate equations for each coagulation trait. The accuracy of the model and the prediction equation was assessed by cross-validation (CRV; 80% training and 20% testing set) and stratified CRV (SCV; 3 breeds in the training set, one breed in the testing set) procedures. Prediction accuracy was assessed by using coefficient of determination of validation (R2VAL), the root mean square error of validation (RMSEVAL), and the ratio performance deviation. Moreover, measured and FTIR predicted traits were compared in the SCV procedure by assessing their least squares means for the breed effect, Pearson correlations, and variance heteroscedasticity. Results showed the feasibility of using FTIR spectra and multivariate analyses to correctly assign milk samples to their breeds of origin. The R2VAL values obtained with the CRV procedure were moderate to high for the majority of coagulation traits, with RMSEVAL and ratio performance deviation values increasing as the coagulation process progresses from rennet addition. Prediction accuracy obtained with the SCV were strongly influenced by the breed, presenting general low values restricting a practical application. In addition, the low Pearson correlation coefficients of Sarda breed for all the traits analyzed, and the heteroscedastic variances of Camosciata delle Alpi, Murciano-Granadina, and Maltese breeds, further indicated that it is fundamental to consider the differences existing among breeds for the prediction of milk coagulation traits.

Many studies focus on the identification of genomic regions that undergo selective processes, where evidence of selection is revealed and positional candidate genes are identified. The aim of the research was to evaluate the association between positional candidate genes, namely secreted phosphoprotein 1 (SPP1, sheep chromosome Ovis aries OAR6, 36.651&ndash, 36.658 Mb), protein O-fucosyltransferase 1 (POFUT1, OAR13, 61.006&ndash, 61.027 Mb) and prolactin receptor (PRLR, OAR16, 38.969&ndash, 39.028 Mb) with milk yield, composition and coagulation traits. Eight single nucleotide polymorphisms (SNPs) mapping to the three genes were genotyped in 380 Sarda dairy sheep. Statistical analysis revealed an association between SNP rs161844011 at SPP1 (chromosome position Oar_v3 OAR6:36651870, gene region exon 7) and somatic cell score, while POFUT1 SNP rs424501869 (OAR13:61007495, intron 1) was associated with curd firmness both 45 and 60 min after rennet addition (p = 0.015 and p = 0.007, respectively). SNP rs400874750 at PRLR gene (OAR16:39004070, intron 2) had a significant association with lactose content (p = 0.020), somatic cell score (p = 0.038), rennet coagulation time (p = 0.018) and curd firming time (p = 0.047). The outcome of this research confirmed predictions based on genomic studies, producing new information regarding the SPP1, POFUT1 and PRLR genes, which may be useful for future breeding schemes.

Little is known about the complex process of cheesemaking at the individual level of dairy goats because of the difficulties of producing a high number of model cheeses. The objectives of this work were (1) to study the cheesemaking ability of goat milk; (2) to investigate the variability of cheesemaking-related traits among different farms; (3) to assess the effects of stage of lactation and parity; and (4) to compare 6 breeds of goat (Saanen and Camosciata delle Alpi for the Alpine type; Murciano-Granadina, Maltese, Sarda and Sarda Primitiva for the Mediterranean type) for their cheesemaking ability. For each goat (n = 560) we studied (1) 8 milk quality traits (fat, protein, total solids, casein, lactose, pH, somatic cell score, and bacterial count); (2) 4 milk nutrient recovery traits (fat, protein, total solids, and energy) in curd; (3) 3 actual cheese yield traits (fresh cheese, cheese solids, and cheese water); (4) 2 theoretical cheese yield values (fresh cheese and cheese solids) and the related cheesemaking efficiencies; and (5) daily milk yield and 3 daily cheese yield traits (fresh cheese, cheese solids, and water retained in the curd). With respect to individual animal factors, farm was not particularly important for recovery traits or actual and theoretical cheese yield and estimates of efficiency, whereas it highly influenced daily productions. Parity of goats influenced daily cheese production, whereas DIM slightly affected recovery as well as percent and daily cheese yield traits. Breed was the most important source of variation for almost all cheesemaking traits. Compared with those of Alpine type, the 4 Mediterranean breeds had, on average, lower daily milk and cheese productions, greater actual and theoretical cheese yield, and higher recovery of nutrients in the curd. Among Alpine type, Camosciata delle Alpi was characterized by greater nutrients recovery than Saanen. Within the 4 Mediterranean types, the 3 Italians produced much less milk per day, with much more fat and protein and greater recovery traits than the Murciano-Granadina, resulting in greater actual cheese yield. Within the Italian breeds, milk from Sarda and Sarda Primitiva was characterized by lower daily yields, higher protein and fat content, and greater recoveries of nutrients than Maltese goats. These results confirmed the potential of goat milk for cheese production and could be useful to give new possibilities and direction in breeding programs.

Traditional milk coagulation properties are used to predict the suitability of milk for cheese-making. In bovine and ovine species, the introduction of the concept of curd firming over time, continuously recorded by a lactodynamograph during prolonged tests, provides additional information about milk coagulation, curd-firming, and syneresis processes. The aims of present study were (1) to test the adaptability of a 4-parameter curd-firming model in the assessment of goat milk (also comparing published data of other species); (2) to describe variability of coagulation, curd firming, and syneresis processes among individual goat milk samples; (3) to quantify the effects of farm and animal factors (breed, parity, and stage of lactation); and (4) to compare 6 goat breeds for their model parameters. Milk samples from 1,272 goats reared in 35 farms were collected. Goats were of 6 breeds: Saanen and Camosciata delle Alpi for the Alpine type; and Murciano-Granadina, Maltese, Sarda, and Sarda Primitiva for the Mediterranean type. During a lactodynamographic analysis (60 min), 240 measures of curd firmness (mm) were recorded for each milk sample. The modeling of curd firming allowed us to achieve the rennet coagulation time estimated on the basis of all the data points (min); the curd firming and the curd syneresis instant rate constants; the asymptotical potential value of curd firming; the actual maximum curd firmness; and the time at which the curd firming maximum level is attained. Modeling parameter data were analyzed using a linear mixed model. Comparison with other dairy species showed several differences: goat milk coagulated later than sheep but earlier than bovine, and curd firming and curd syneresis instant rate constants were greater in small ruminants. Modeling parameters of goat milk were mostly affected by the farm effect (37% of the total variance, on average) compared with the results found for bovine and ovine samples, and this was probably attributable to the marked differences among goat farming systems. Small differences were demonstrated between Alpine and Mediterranean breeds, but the time of maximum curd firmness was lower in Murciano-Granadina compared with Maltese, Sarda, and Sarda Primitiva. Sarda and Sarda Primitiva were very similar and exhibited the most favorable coagulation properties of milk. For almost all the model parameters, the direct effect of breed was increased after correction for milk yield and composition. In conclusion, this approach allowed us to fully depict the effects of the different factors on coagulation of goat milk, and clarified the different renneting pattern among goat breeds, and with other species. Results could be used for the valorization of goat dairy products, also when these are linked to particular local breeds, and to stimulate further studies about relationships between coagulation and cheese-making traits.

Goat milk and cheese production is continuously increasing and milk composition and coagulation properties (MCP) are useful tools to predict cheesemaking aptitude. The present study was planned to investigate the extension of lactodynamographic analysis up to 60 min in goat milk, to measure the farm and individual factors, and to investigate differences among 6 goat breeds. Daily milk yield (dMY) was recorded and milk samples collected from 1,272 goats reared in 35 farms. Goats were of 6 different breeds: Saanen and Camosciata delle Alpi for the Alpine type, and Murciano-Granadina, Maltese, Sarda, and Sarda Primitiva for the Mediterranean type. Milk composition (fat, protein, lactose, pH; somatic cell score; logarithmic bacterial count) and MCP [rennet coagulation time (RCT, min), curd-firming time (k20, min), curd firmness at 30, 45, and 60 min after rennet addition (a30, a45, and a60, mm)] were recorded, and daily fat and protein yield (dFPY g/d) was calculated as the sum of fat and protein concentration multiplied by the dMY. Data were analyzed using different statistical models to measure the effects of farm, parity, stage of lactation and breed; lastly, the direct and the indirect effect of breed were quantified by comparing the variance of breed from models with or without the inclusion of linear regression of fat, protein, lactose, pH, bacterial, somatic cell counts, and dMY. Orthogonal contrasts were performed to compare least squares means. Almost all traits exhibited high variability, with coefficients of variation between 32 (for RCT) and 63% (for a30). The proportion of variance regarding dMY, dFPY, and milk composition due to the farm was moderate, whereas for MCP it was low, except for a60, at 69%. Parity affected both yield and quality traits of milk, with least squares means of dMY and dFPY showing an increase and RCT and curd firmness traits a decrease from the first to the last parity class. All milk quality traits, excluding fat, were affected by the stage of lactation; RCT and k20 decreased rapidly and a30 was higher from the first to the last part of lactation. Alpine breeds showed the highest dMY and dFPY but Mediterranean the best percentage of protein, fat, and lactose and a shorter k20 and a greater a30. Among the Mediterranean goats, Murciano-Granadina goats had the highest milk yield, fat, and protein contents, whereas Maltese, Sarda, and Sarda Primitiva were characterized by much more favorable technological properties in terms of k20, a30, and a45. In conclusion, as both the farm and individual factors highly influenced milk composition and MCP traits, improvements of these traits should be based both on modifying management and individual goat factors. As expected, several differences were attributable to the breed effect, with the best milk production for the Alpines and milk quality and coagulation for the Mediterranean goats.

The present study investigated the effect of somatic cell count, lactose, and pH on sheep milk composition, coagulation properties (MCP), and curd firming (CF) parameters. Individual milk samples were collected from 1,114 Sarda ewes reared in 23 farms. Milk composition, somatic cell count, single point MCP (rennet coagulation time, RCT; curd firming time, k 20 ; and curd firmness, a 30 , a 45 , and a 60 ), and CF model parameters were achieved. Phenotypic traits were statistically analyzed using a mixed model to estimate the effects of the different levels of milk somatic cell score (SCS), lactose, and pH, respectively. Additive genetic, herd, and residual correlations among these 3 traits, and with milk composition, MCP and CF parameters, were inferred using a Bayesian approach. From a phenotypic point of view, higher SCS levels caused a delayed gelification of milk. Lactose concentration and pH were significant for many milk quality traits, with a very intense effect on both coagulation times and curd firming. These traits (RCT, RCT estimated using the curd firming over time equation, and k 20 ) showed an unfavorable increase of about 20% from the highest to the lowest level of lactose. Milk samples with pH values lower than 6.56 versus higher than 6.78 were characterized by an increase of RCT (from 6.00 to 14.3 min) and k 20 (from 1.65 to 2.65 min) and a decrease of all the 3 curd firmness traits. From a genetic point of view, the marginal posterior distribution of heritability estimates evidenced a large and exploitable variability for all 3 phenotypes. The mean intra-farm heritability estimates were 0.173 for SCS, 0.418 for lactose content, and 0.206 for pH. Lactose (favorably), and SCS and pH (unfavorably), at phenotypic and genetic levels, were correlated mainly with RCT and RCT estimated using the curd firming over time equation and scarcely with the other curd firming traits. The SCS, lactose, and pH were significantly correlated with each other's. In conclusion, results reported in the present study suggest that SCS, pH, and lactose affect, contemporarily and independently, milk quality and MCP. These phenotypes, easily available during milk recording schemes measured by infrared spectra prediction, could be used as potential indicators traits for improving cheese-making ability of ovine milk.

Maedi–Visna virus (MVV) and Mycobacterium avium ssp. paratuberculosis (MAP) are two pathogens that cause chronic, production-limiting diseases in dairy sheep. Although they are present worldwide, there are no detailed reports on their actual effects on milk traits in the literature. This study was designed to investigate the effects of test positivity to MVV and MAP on ovine milk yield, composition and coagulation properties, and curd-firming over time (CFt) variables in clinically healthy animals at the field level. The additive genetic variation and heritabilities of MVV and MAP positivity were also estimated. Milk samples were collected from 1,079 Sarda sheep kept on 23 farms, and pedigree information was obtained from the flock book. Milk yield was also recorded on the sampling date. Positivity for MVV and MAP was determined from milk samples using indirect ELISA test kits. Milk composition traits were measured by spectroscopy, milk coagulation properties were measured with a Formagraph (Foss Italia, Padua, Italy), and CFt traits were calculated using the data from the Formagraph diagram. The effects of MVV and MAP positivity on milk traits were determined through a set of mixed linear models, which took into account various sources of variation, such as days in milk, parity, and flock effects, and included the effects (positive or negative) of the 2 pathogens. A Bayesian threshold sire model with sire relationship was used to estimate genetic variation and heritability. The overall animal prevalence of MVV-positive ewes was 43.6%; on only 1 farm of the 23 tested were all sampled ewes negative. An overall animal prevalence of 10.6% was recorded for MAP, with 4 farms at 0%. Positivity for MVV significantly affected the logarithmic score of the bacterial count, curd firmness after 30 min and 45 min, and the curd-firming instant rate constant. We found significant effects of MAP infection on milk composition, pH, and rennet coagulation time. The mean of the posterior distributions of heritability estimates on the liability scale was 0.15 for MAP and 0.07 for MVV. Our results demonstrate that only a few traits are negatively affected by MVV and MAP positivity, and that there is exploitable genetic variation in MVV and MAP susceptibility in dairy sheep.

Simple Summary Domestic goats show extraordinary adaptation to different environments. Sardinia (Italy), the second-largest island in the Mediterranean Sea, is the birthplace of Sarda goats which are raised to produce milk mainly devoted to cheesemaking. The aim of this research was to characterize genetic diversity of Sarda bucks, reared in eight subregions of the island, to gain information about the relationship between genetic variation and geography as well as to investigate the existence of population substructure. We performed genotyping of Y-chromosome markers, which trace the patrilineal diversity, and sequencing of a portion of mitochondrial DNA, which gives information about matrilineal diversity. Analysis of Y-chromosome markers revealed the occurrence of high levels of diversity in populations from Southwest Sardinia. Further analysis of both Y-chromosome and mitochondrial DNA data evidenced the lack of population substructure. These results suggest the occurrence of extensive gene flow between the different subregions of Sardinia. The introduction of goats from other geographical locations, outside Sardinia, and belonging to highly productive breeds probably contributed to enhance genetic variation. Abstract A sample of 146 Sarda bucks from eight subregions of Sardinia, Italy (Nuorese, Barbagia, Baronia, Ogliastra, Sarrabus, Guspinese, Iglesiente, Sulcis) were characterized for Y-chromosome and mtDNA markers to assess the levels of population substructure. Five polymorphic loci (SRY, AMELY, ZFY, and DDX3Y) on the Y-chromosome were genotyped. The control region of mtDNA was sequenced as a source of complementary information. Analysis of Y-chromosome data revealed the segregation of 5 haplotypes: Y1A (66.43%), Y2 (28.57%), Y1C (3.57%), Y1B1 (0.71%), and Y1B2 (0.71%). High levels of Y-chromosome diversity were observed in populations from Southwest Sardinia. The FST values based on Y-chromosome and mtDNA data were low, although a paternal genetic differentiation was observed when comparing the Nuorese and Barbagia populations (Central Sardinia) with the Sulcis, Iglesiente, and Sarrabus populations (Southern Sardinia). AMOVA analysis supported the lack of population substructure. These results suggest the occurrence of a historical and extensive gene flow between Sarda goat populations from different locations of Sardinia, despite the fact that this island is covered by several large mountain ranges. Introgression with foreign caprine breeds in order to improve milk production might have also contributed to avoiding the genetic differentiation amongst Sarda populations.

The aims of this study were to explore the variability of milk composition, coagulation properties, and cheese-making traits of the Sarda goat breed, and to investigate the effects of animal and farm factors, and the geographic area (Central-East vs. South-West) of an insular region of Italy, Sardinia. A total of 570 Sarda goats reared in 21 farms were milk-sampled during morning milking. Individual milk samples were analyzed for composition, traditional milk coagulation properties (MCP), modeled curd-firming over time parameters (CFt), and cheese-making traits (cheese yield, %CY; recovery of nutrients, %REC; daily cheese yield, dCY). Farms were classified into 2 categories based on milk energy level (MEL; high or low), defined according to the average net energy of milk daily produced by the lactating goats. Milk yield and composition were analyzed using a mixed model including the fixed effects of MEL, geographic area, days in milk, and parity, and the random effect of farm within MEL and geographic area. Data about MCP, CFt, and the cheese-making process were analyzed using the same model, with the inclusion of the effects of animal and pendulum of the lactodynamograph instrument, allowing the measure of repeatability of these traits. Results showed that animal had greater influence on coagulation and cheese-making traits compared with farm effect. Days in milk influenced milk composition, whose changes partly reflected the modifications of %CY traits. Moreover, large differences were observed between primiparous and multiparous goats: primiparous goats produced less milk of better quality (higher fat, lower somatic cell and bacterial counts) and less cheese, but with higher recovery of fat and protein in the curd, compared with multiparous goats. The repeatability was very high, for both coagulation (84.0 to 98.8%) and cheese-making traits (89.7 to 99.9%). The effect of MEL was significant for daily productions of milk and cheese, coagulation time, and recovery of protein in the curd, which were better in high-MEL farms. As regards geographic area, milk composition and percentage cheese yield were superior in the Central-East area, whereas daily milk and cheese production and MCP were better in the South-West. This result was explainable by the phenomenon of crossbreeding Sarda goats with Maltese bucks, which occurred with greater intensity in the South-West than in the Central-East area of the island. The results provided by this study could be of great interest for the goat dairy sector. Indeed, the methods described in the present study could be applicable for other farming methods, goat breeds, and geographic areas. The collection of a wide range of phenotypes at individual animal level is fundamental for the characterization of local populations and can be used to guarantee breed conservation and the persistence of traditional farming systems, and to increase farmers' profit.

The aims of the present research were to quantify the effects of each coagulation trait, traditional milk coagulation properties [MCP: rennet coagulation time (RCT), curd-firming time (k20), and curd firmness at 30 min (a30)], and modeled curd-firming over time (CFt) parameters [estimated rennet coagulation time (RCTeq), curd-firming instant rate constant (kCF), and potential curd firmness (CFP)] directly on the following: (1) recovery of 3 milk components in the curd (%REC), (2) 3 measures of cheese yield (%CY), and (3) 3 daily cheese yield traits (dCY) from goat milk. Cheese-making traits were analyzed using 2 mixed different models, the first to test MCP and the second to test CFt parameters. Pearson correlations were also calculated. Significant and favorable relationships (negative for time intervals and positive for CF measures) were found between the traditional MCP and the CFt parameters and %REC and %CY traits. The effects of milk fat and protein contents were particularly important on all cheese-making traits, with the only exception being the effect of fat content on water retention in cheese (%CYWATER). We found an optimum value of milk k20, associated with the highest recovery of components and cheese yield in solids (%CYSOLIDS). In addition, a lower level of curd water retention and an increased fresh curd yield (%CYCURD) were associated with greater recovery of fat. The collection of all available information during the process of milk coagulation and curd-firming allowed us to discover the effect of RCTeq on %REC traits and %CYSOLIDS, which had not previously been revealed for traditional RCT. Moreover, higher kCF values were associated with increased %CYCURD and %CYSOLIDS. Given that CFt parameters showed a high level of independence from one another, these can also be easily used and characterized in future applications at the industry level. Information provided by traditional and modeled coagulation properties could efficiently support the goat dairy industry and lay the foundations for a quality payment scheme for goat milk.

Individual milk samples from 169 Sarda sheep were collected to characterise the cheese-making potential through the use of a laboratory bench-top model cheese-manufacturing procedure. As the milk samples were not standardised before processing, the data collected at laboratory level fully reflected the great variability of milk from individual animals. The average cheese yield traits of fresh cheese, cheese dry matter and water retained in cheese (as percentages of the milk processed) were 20.6%, 10.1% and 10.6%. The average milk fat and protein recoveries in the curd were 94.0% and 76.7%, respectively. The values for daily production of curd and curd dry matter per sheep were 0.41 kg d −1 and 0.20 kg d −1 , respectively. The cheese yield and cheese-related traits were mainly affected by the nutrient content of the milk and the individual effects of the stage of lactation and daily milk yield, respectively, but also by a large individual variation.

Dairy goat farming is practiced worldwide, within a range of different farming systems. Here we investigated the effects of environmental factors and morphology on milk traits of the Sardinian goat population. Sardinian goats are currently reared in Sardinia (Italy) in a low-input context, similar to many goat farming systems, especially in developing countries. Milk and morphological traits from 1,050 Sardinian goats from 42 farms were recorded. We observed a high variability regarding morphological traits, such as coat color, ear length and direction, horn presence, and udder shape. Such variability derived partly from the unplanned repeated crossbreeding of the native Sardinian goats with exotic breeds, especially Maltese goats. The farms located in the mountains were characterized by the traditional farming system and the lowest percentage of crossbred goats. Explanatory factors analysis was used to summarize the interrelated measured milk variables. The explanatory factor related to fat, protein, and energy content of milk (the "Quality" latent variable) explained about 30% of the variance of the whole data set of measured milk traits followed by the "Hygiene" (19%), "Production" (19%), and "Acidity" (11%) factors. The "Quality" and "Hygiene" factors were not affected by any of the farm classification items, whereas "Production" and "Acidity" were affected only by altitude and size of herds, respectively, indicating the adaptation of the local goat population to different environmental conditions. The use of latent explanatory factor analysis allowed us to clearly explain the large variability of milk traits, revealing that the Sardinian goat population cannot be divided into subpopulations based on milk attitude The factors, properly integrated with genetic data, may be useful tools in future selection programs.

In dairy goats, very little is known about the effect of the 2 most important indirect indicators of udder health [somatic cell count (SCC) and total bacterial count (TBC)] on milk composition and cheese yield, and no information is available regarding the effects of lactose levels, pH, and NaCl content on the recovery of nutrients in the curd, cheese yield traits, and daily cheese yields. Because large differences exist among dairy species, conclusions from the most studied species (i.e., bovine) cannot be drawn for all types of dairy-producing animals. The aims of this study were to quantify, using milk samples from 560 dairy goats, the contemporary effects of a pool of udder health indirect indicators (lactose level, pH, SCC, TBC, and NaCl content) on the recovery of nutrients in the curd (%REC), cheese yield (%CY), and daily cheese yields (dCY). Cheese-making traits were analyzed using a mixed model, with parity, days in milk (DIM), lactose level, pH, SCC, TBC, and NaCl content as fixed effects, and farm, breed, glass tube, and animal as random effects. Results indicated that high levels of milk lactose were associated with reduced total solids recovery in the curd and lower cheese yields, because of the lower milk fat and protein contents in samples rich in lactose. Higher pH correlated with higher recovery of nutrients in the curd and higher cheese yield traits. These results may be explained by the positive correlation between pH and milk fat, protein, and casein in goat milk. High SCC were associated with higher recovery of solids and energy in the curd but lower recovery of protein. The higher cheese yield obtained from milk with high SCC was due to both increased recovery of lactose in the curd and water retention. Bacterial count proved to be the least important factor affecting cheese-making traits, but it decreased daily cheese yields, suggesting that, even if below the legal limits, TBC should be considered in order to monitor flock management and avoid economic losses. The effect of NaCl content on milk composition was linked with lower recovery of all nutrients in the curd during cheese-making. In addition, high milk NaCl content led to reductions in fresh cheese yield and cheese solids. The indirect indicators of the present study significantly affected the cheese-making process. Such information should be considered, to adjust the milk-to-cheese economic value and the milk payment system.

Cheese yield is strongly influenced by the composition of milk, especially fat and protein contents, and by the efficiency of the recovery of each milk component in the curd. The real effect of milk composition on cheesemaking ability of goat milk is still unknown. The aims of this study were to quantify the effects of milk composition; namely, fat, protein, and casein contents, on milk nutrient recovery in the curd, cheese yield, and average daily yield. Individual milk samples were collected from 560 goats of 6 different breeds. Each sample was analyzed in duplicate using the 9-laboratory milk cheesemaking assessment, a laboratory method that mimicked cheesemaking procedures, with milk heating, rennet addition, coagulation, curd cutting, and draining. Data were submitted to statistical analysis; results showed that the increase of milk fat content was associated with a large improvement of cheese yield because of the higher recovery of all milk nutrients in the curd, and thus a higher individual daily cheese yield. The increase of milk protein content affected the recovery of fat, total solids, and energy in the curd. Casein number, calculated as casein-to-protein ratio, did not affect protein recovery but strongly influenced the recovery of fat, showing a curvilinear pattern and the most favorable data for the intermediate values of casein number. In conclusion, increased fat and protein contents in the milk had an effect on cheese yield not only for the greater quantity of nutrients available but also for the improved efficiency of the recovery in the curd of all nutrients. These results are useful to improve knowledge on cheesemaking processes in the caprine dairy industry.

The present study investigated the effect of different levels of fat, protein, and casein on (1) traditional milk coagulation properties, and (2) curd firming over time parameters of 1,272 goat milk samples. Relationships between fat, protein, and casein and some indicators of udder health status (lactose, pH, somatic cells, bacterial count, and NaCl) were also investigated. Traditional milk coagulation properties and modeled curd-firming parameters were analyzed using a mixed model that considered the effect of days in milk, parity, farm, breed, the pendulum of the instrument, and different levels of fat, protein, and casein. Fat, protein, and casein were also tested with the same model but one at a time. Information provided by this model demonstrated the effect of one component alone, without contemporarily considering that of the others. The results allowed us to clarify the effect of the major milk nutrients on coagulation, curd firming, and syneresis ability of goat milk. In particular, milk rich in fat was associated with better coagulation properties, whereas milk rich in protein was associated with delayed coagulation. The high correlation of fat with protein and casein contents suggests that the effect of fat on the cheese-making process is also attributable to the effects of protein and casein. When only protein or only casein was included in the statistical model, the pattern of coagulation, curd firming, and syneresis was almost indistinguishable. The contemporary inclusion of protein and casein in the statistical model did not generate computing problems and allowed us to better characterize the role of protein and casein. Consequently, given their strong association, we also tested the effect of casein-to-protein ratio (i.e., casein number). Higher values of casein number led to a general improvement in the coagulation ability of milk, suggesting that casein-to-protein ratio, not just protein or casein, should be considered when milk is destined for cheese making. These results are especially useful for dairy farmers who want to increase their profits by improving the technological quality of the milk produced.

The aim of this study was to evaluate a 3-min assay (Betastar® Combo 3.0) for the detection of Penicillin G, Amoxicillin, Cefazolin and Oxytetracycline hydrochloride in individual ewe milk. Antibiotics-free samples were obtained throughout three trials from three Sarda ewes. At the laboratory, samples were spiked with the four antimicrobial molecules at different concentrations. These were on the basis of the specific maximum residue limits fixed by the European Union (MRLs): 4 μg/kg for Penicillin G, 4 μg/kg for Amoxicillin, 50 μg/kg for Cefazolin and 100 μg/kg for Oxytetracycline. Negative control samples (180 tests) were always detected as negative. The limit of detection for Penicillin was lower than the MRL, whereas for Amoxicillin and Oxytetracycline it was slightly higher than the MRL in one case out of nine examinations. The limit of detection for Cefazolin was higher than the MRL. In conclusion, Betastar® Combo 3.0 was suitable for rapid screening of individual sheep milk spiked with Penicillin G, Amoxicillin and Oxytetracycline.

Growth hormone (GH) is encoded by theGHgene, which may be single copy or duplicate in sheep. The two copies of the sheep GH gene (GH1/GH2-NandGH2-Z) were entirely sequenced in one 106 ewes of Sarda breed, in order to highlight sequence polymorphisms and investigate possible association between genetic variants and milk traits. Milk traits included milk yield, fat, protein, casein and lactose percentage. We evidenced 75 nucleotide changes. Transcription factor binding site prediction revealed two sequences potentially recognised by the pituitary-specific transcription factorPOU1FIat theGH1/GH2-Ngene, which were lost at the promoter ofGH2-Z, which might explain the different tissues of expression ofGH1/GH2-N(pituitary) andGH2-Z(placenta). Significant differences in milk traits were observed among genotypes at polymorphic loci only for theGH2-Zgene. Sheep with homozygote genotype ss748770547 CC had higher fat percentage (P GH2-Zgene 5′ flanking region, may be a causal mutation affecting milk fat content. These findings might contribute to the knowledge of the sheepGHlocus and might be useful in selection processes in sheep.

The growth hormone receptor (GHR), the growth hormone releasing hormone receptor (GHRHR), and the insulin-like growth factor 1 (IGF1) genes are known to modulate growth, reproduction, and lactation traits in livestock. The aim of the current work was to investigate if the variation of the sheep GHR, GHRHR, and IGF1 genes is associated with milk yield and quality traits. Three hundred eighty dairy Sarda sheep were genotyped for 36 single nucleotide polymorphisms (SNP) mapping to these 3 loci, and records for milk yield and daily fat and protein yield, as well as for fat, protein, casein, lactose, and milk urea contents, pH, somatic cell score, logarithmic bacterial count, and milk energy were obtained. The linkage disequilibrium analysis was performed only for GHR, as both GHRHR and IGF1 had only 1 polymorphic SNP. Haplotype analysis revealed the existence of 7 haplotype blocks in GHR. Two haplotype blocks, including part of the intron 1 and the upstream region, were clearly separated from the remaining 5 blocks by SNP rs412986330, which may be a recombination hotspot. The latter 5 blocks were contiguous, spanning from intron 2 to exon 10. Statistical analysis revealed that the GHR polymorphism is significantly associated with milk traits for daily fat and protein yield and fat, milk urea, and lactose content. Moreover, variation in IGF1 was associated with milk protein and casein content. Data generated in this research provide new insights into the allelic effects of the ovine GHRHR, GHR, and IGF1 genes on milk production and quality traits, information that may be useful in gene-assisted selection programs., This research was funded by the Regione Autonoma della Sardegna (Cagliari, Italy; MIGLIOVIGENSAR - CUP: B82I13000580002).

The importance of milk coagulation properties for milk processing, cheese yield, and quality is widely recognized. The use of traditional coagulation traits presents several limitations for testing bovine milk and even more for sheep milk, due to its rapid coagulation and curd firming, and early syneresis of coagulum. The aim of this technical note is to test and improve model fitting for assessing coagulation, curd firming, and syneresis of sheep milk. Using milk samples from 87 Sarda ewes, we performed in duplicate lactodynamographic testing. On each of the 174 analyzed milk aliquots, using 180 observations from each aliquot (one every 15 s for 45 min after rennet addition), we compared 4 different curd firming models as a function of time (CFt, mm) using a nonlinear procedure. The most accurate and informative results were observed using a modified 4-parameter model, structured as follows: [Formula: see text] where t is time, RCTeq (min) is the gelation time, CFP (mm) is the potential asymptotical CF at an infinite time, kCF (%/min) is the curd firming rate constant, and kSR (%/min) is the curd syneresis rate constant. To avoid nonconvergence and computational problems due to interrelations among the equation parameters, CFP was preliminarily defined as a function of maximum observed curd firmness (CFmax, mm) recorded during the analysis. For this model, all the modeling equations of individual sheep milk aliquots were converging, with a negligible standard error of the estimates (coefficient of determination >0.99 for all individual sample equations). Repeatability of the modeled parameters was acceptable, also in the presence of curd syneresis during the lactodynamographic analysis.

This study was conducted, in an extensive farm, to assess the effects of artificial feeding with an acidified milk replacer on productive performance of goat kids. Thirty-two Sarda kids, randomly divided into two feeding groups of 16 kids, (NM, naturally milk fed by their dams, and AR, artificially bottle-fed with an acidified milk replacer) were weighed at weekly intervals until slaughtering, at 42 days of age. A blood sample was collected from each goat kid before slaughter for the assessment of the metabolic status. Post-mortem data were registered: carcass characteristics; percentages of commercial cuts; muscle, separable fat and bone + tendons percentage. Results were analysed by a General Linear Model procedure. The two feeding groups showed similar live weights, except for the period between 7 and 21 days of age. As regards slaughter data, AR kids had a reduced fat deposition and carcasses with shorter diameters and a longer leg. Measurements after dissection showed that the muscle/fat ratio was more favourable in AR kids. Although there were some differences between the groups, haematochemical parameters of both NM and AR were in the range reported for goat kids. On the basis of the results of this trial, artificial feeding with an acidified milk replacer can provide carcasses similar to those obtained with natural milk feeding and can be used both for goat kid meat production and eradication schemes of diseases transmitted by milk-feeding.

Summary The aim of the current work was to analyze, in the Sarda breed goat, genetic polymorphism within the casein genes and to assess their influence on milk traits. Genetic variants at the CSN1S1, CSN2, CSN1S2 and CSN3 gene loci were investigated using PCR-based methods, cloning and sequencing. Strong alleles prevailed at the CSN1S1 gene locus and defective alleles also were revealed. Null alleles were evidenced at each calcium-sensitive gene locus. At the CSN3 gene locus, we observed a prevalence of the CSN3 A and B alleles; the occurrence of rare alleles such as CSN3 B'', C, C', D, E and M; and the CSN3 S allele (GenBank KF644565) described here for the first time in Capra hircus. Statistical analysis showed that all genes, except CSN3, significantly influenced milk traits. The CSN1S1 BB and AB genotypes were associated with the highest percentages of protein (4.41 and 4.40 respectively) and fat (5.26 and 5.34 respectively) (P

This study investigated the influence of casein genes polymorphism on renneting properties of milk from Sarda goats. Milk yield and composition, and renneting properties (rennet coagulation time RCT, firming time k20 and curd firmness a30) were evaluated in 200 multiparous goats from three farms, at monthly intervals from March to July. Animals were genotyped at CSN1S1 , CSN2 , CSN1S2 and CSN3 . Statistical analysis was performed by a repeated measures General Linear Model. CSN1S1 significantly affected milk traits with a lower fat content registered for goats carrying the F allele. The highest protein concentration was recorded for the CSN1S1 AB goats. Milk from CSN1S1 FF homozygote goats was characterized by a delayed k20 and the CSN1S1 AB showed a higher a30. All the parameters were influenced by the CSN2 locus, except milk yield. Polymorphism at CSN1S2 influenced only daily milk yield and a30. The CSN1S2 0 null allele was detected for the first time in this breed. The influence of genotype effect was particularly marked for CSN3 ; RCT and k20 were delayed in CSN3 BB goats and the highest level of a30, 47.88 mm registered for CSN3 AA goats, could be considered remarkable when compared to other goat breeds or populations. In conclusion, this study improved knowledge on the effects of goat casein genes on milk renneting parameters, and could be useful in the future planning of breeding programs and specific dairy products linked to the Sarda breed (PDO/PGI).

The purpose was to analyze the growth hormone GH1/GH2-N and GH2-Z gene copies and to assess their possible association with milk traits in Sarda sheep. Two hundred multiparous lactating ewes were monitored. The two gene copies were amplified separately and each was used as template for a nested PCR, to investigate single strand conformation polymorphism (SSCP) of the 5′UTR, exon-1, exon-5 and 3′UTR DNA regions. SSCP analysis revealed marked differences in the number of polymorphic patterns between the two genes. Sequencing revealed five nucleotide changes at the GH1/GH2-N gene. Five nucleotide changes occurred at the GH2-Z gene: one was located in exon-5 (c.556G > A) and resulted in a putative amino acid substitution G186S. All the nucleotide changes were copy-specific, except c.*30delT, which was common to both GH1/GH2-N and GH2-Z. Variability in the promoter regions of each gene might have consequences on the expression level, due to the involvement in potential transcription factor binding sites. Both gene copies influenced milk yield. A correlation with milk protein and casein content was also evidenced. These results may have implications that make them useful for future breeding strategies in dairy sheep breeding.

The aim of this research was to investigate variability in each of the five exons of the caprine growth hormone (gGH) gene, in order to establish the possible relationships with milk traits in Sarda breed goat. The general linear model procedure was used to analyse the effects of the single strand conformation (SSCP) profiles on milk traits of 100 lactating goats. Analysis of conformational polymorphism at exons 1–5 revealed a total of 25 differing banding patterns. Sequencing revealed 21 nucleotide changes (compared with GenBank D00476): 14 were polymorphic and 7 monomorphic; 19 in exonic regions, 5 of which were nonsynonymous. A SNP upstream of the transcription initiation codon (c.-3A>G) and an indel (c.*29_30insC) in the 3′UTR, were detected. Alignment of 4 cloned sequences including the entiregGHgene led to the identification of 22 nucleotide variations within the intron regions, including two indels. Association analysis revealed that each exon, except exon-1, affected milk yield, exons 1 and 3 influenced milk fat percentage, and all exons, except exon-2, had an effect on protein percentage, supporting previous results in livestock. The variability detected at the caprineGHgene might provide useful information for the phylogeny of ruminants and, more importantly, have implications on the biological function of the growth hormone and on those traits resulting from its physiological action, including milk production and composition. The caprineGHgene may become a useful molecular marker for a more effective genetic selection for milk production traits in goats.

Goat farming represents an important livestock sector in Sardinia, an insular region of Italy, being exploited approximately 300,000 heads in this region. The Sarda goat is the autochthonous breed of the Island with a census of 29,000 animals recorded in the official herd book. It is perfectly adapted to the semiarid environment and farming is mainly based on traditional and semi-extensive methods, grazing free pasture of the Mediterranean scrubland. Sarda is a small-size dairy breed and milk is mainly used for cheese-making. Daily milk yield ranges from 0.4 to 1 kg, while protein and fat contents range 3.7–4.3 and 4.5–6.0 g/100 mL, respectively. Favorable values of milk coagulation properties and cheese yield are also reported. The authors evidence the high variability in candidate gene and the positive effect on milk characteristics, in comparison with other specialized breeds. These productive and genetic characteristics are the strongest points of the Sarda goat, whereas the constant and unplanned importation of cosmopolitan specialized breeds along with and the absence of labeled products strictly linked to the Sarda breed are the weakest points.

The effect ofCSN1S1genotype and lactation stage on milk yield and composition were investigated in 80 extensively reared goats. Milk yield was recorded in early, mid and late lactation and individual milk samples were collected to determine: fat, protein, lactose and casein content, pH, freezing point, somatic cell count (SCC) and total microbic mesophilic count (TMC). Relative casein composition and amino acid profile were quantified by HPLC. Fatty acid profile was measured by gas-chromatography. Genotype did not affect milk yield, while this trait was significantly affected by lactation stage (P CSN1S1BB goats produced significantly higher protein and casein percentages (P s1-casein (CN) was significantly higher in BB and AB goats than AF and BF, showing intermediate values in AA goats (P s1and αs2-CN fractions were not affected by lactation stage, while the casein content and the β and κ-CN significantly increased throughout lactation (P

Sheep milk is an important source of food, especially in Mediterranean countries, and is used in large part for cheese production. Milk technological traits are important for the sheep dairy industry, but research is lacking into the genetic variation of such traits. Therefore the aim of this study was to estimate the heritability of traditional milk coagulation properties and curd firmness modeled on time t (CFt) parameters, and their genetic relationships with test-day milk yield, composition (fat, protein, and casein content), and acidity in Sarda dairy sheep. Milk samples from 1,121 Sarda ewes from 23 flocks were analyzed for 5 traditional coagulation properties by lactodynamographic tests conducted for up to 60min: rennet coagulation time (min), curd-firming time (k20, min), and 3measures of curd firmness (a30, a45, and a60, mm). The 240 curd firmness observations (1 every 15 s) from each milk sample were recorded, and 4 parameters for each individual sample equation were estimated: rennet coagulation time estimated from the equation (RCTeq), the asymptotic potential curd firmness (CFP), the curd firming instant rate constant (kCF), and the syneresis instant rate constant (kSR). Two other derived traits were also calculated (CFmax, the maximum curd firmness value; and tmax, the attainment time). Multivariate analyses using Bayesian methodology were performed to estimate the genetic relationships of milk coagulation properties and CFt with the other traits; statistical inference was based on the marginal posterior distributions of the parameters of concern. The marginal posterior distribution of heritability estimates of milk yield (0.16±0.07) and composition (0.21±0.11 to 0.28±0.10) of Sarda ewes was similar to those often obtained for bovine species. The heritability of rennet coagulation time as a single point trait was also similar to that frequently obtained for cow milk (0.19±0.09), whereas the same trait calculated as an individual equation parameter exhibited larger genetic variation and a higher heritability estimate (0.32±0.11). The other curd firming and syneresis traits, whether as traditional single point observations or as individual equation parameters and derived traits, were characterized by heritability estimates lower than for coagulation time and for the corresponding bovine milk traits (0.06 to 0.14). Phenotypic and additive genetic correlations among the 11 technological traits contribute to describing the interdependencies and meanings of different traits. The additive genetic relationships of these technological traits with the single test-day milk yield and composition were variable and showed milk yield to have unfavorable effects on all measures of curd firmness (a30, a45, a60, CFP, and CFmax) and tmax, but favorable effects on both instant rate constants (kCF and kSR). Milk fat content had a positive effect on curd firmness traits, especially on those obtained from CFt equations, whereas the negative effects on both coagulation time traits were attributed to the milk protein and casein contents. Finally, in view of the estimated heritabilities and additive genetic correlations, enhancement of technological traits of sheep milk through selective breeding could be feasible in this population.

The aim of the study was to detect polymorphism in the POU1F1 gene in Sarda breed goat, as well as to establish if SNPs could be associated with milk productive traits. The research was conducted on 129 Sarda breed goats from 4 to 5 years old, multiparous, lactating and in their third to fifth lactation. We report nine exonic and seven non-coding regions SNPs within the Sarda goat POU1F1 gene, namely, Ex 1 61 G>C; Ex 1 108 G>A; Ex 3 C>T; Ex 3 92 C>T; Ex 4 110 A>G; Ex 5 34 G>A resulting in Arg213Lys change; IVS4 641 G>A, IVS4 643 A>C, IVS4 659 G>A, IVS4 677 A>C, IVS4 G699Del, IVS4 709 C>G, Ex 6 17 G>A resulting in Arg228Ser change, Ex 6 58 G>T, Ex 6 172 T>C, 3′UTR 110 T>C. A statistically significant association was found between genotype TT, in position 17 of the exon 6 (3.1 % of frequency), and increased milk yield (P < 0.01) while genotype GT (25.6 % of frequency) was associated with a higher fat content. Genotype TT in position 58 of the exon 6 (3.9 % of frequency) was found to be associated with a higher fat (P < 0.01) and protein content (P < 0.05). Twenty-eight haplotypes were detected, but no significant association between the haplotypes and the milk production traits have been found. Our data, as well as providing new SNPs extending the POU1F1 gene characterization, evidence a relationship between polymorphism and milk production traits in Sarda goat breed.