α_S1-casein genetic variants in Sarda goat breed

Sardinia plays an important role in Italian goat breeding; this is due not only to the high extent of its patrimony and production, but also to the fact that the main breed, the Sarda goat, represents an interesting biodiversity source. As regards the morphologic variability, marked differences between subjects reared in the coast and mountain areas were found (Macciotta et al., 2002). These differences are due to the genetic selection on the autochthonous patrimony, set up by breeders and based on coat colour, horn presence and/or on functional criteria (udder shape). The need to improve milk yields also induced various breeders, mainly in those areas with better pasture conditions, to crossbreed the Sarda goats with more productive breeds. The present situation (Pazzola et al., 2002) shows how in the East coastal region (Sarrabus, Ogliastra and Baronia) and in the central mountain areas of Sardinia (Barbagia), subjects with more rural traits are reared (smaller size, small ears, presence of horns, etc.); while in the South and West areas (Sulcis and Guspinese) the influence of the Maltese breed is more evident. Both the productive traits variability (Brandano et al., 1978), and the morphologic aspect, is of great interest. Genetic variability can influence the survival of a sector hindered by the opening of the markets and by the strong competitiveness of zootechnical areas technologically more advanced. According to this point of view, considering that casein fractions are closely related to milk technological characteristics (Grosclaude et al., 1994), and to its possible productive differentiation (Remeuf, 1993), a study on αS1-casein allelic frequency was carried out, related also to the breeding region. The aim of the study is to acquire useful information in order to suggest an appropriate utilization of milk, to detect possible new alleles and to test the correlation between casein phenotype and morphology of the animals

Influence of body weight on reproductive activity in Sarda female lambs

One way to improve reproductive performance of ewes is through extending its lifetime productivity. Breeding ewe lambs is one method of improving the reproductive performance in the sheep. In order to produce an offspring when the ewe lamb is approximately 1 yr of age, the autumn-born ewe must obtain puberty before the autumn breeding season begins. Onset of puberty is determined by integration of both internal and external factors, which then enable the neuroendocrine or hormonal event occur (Shirley et al., 2001). Age, photoperiod and body weight are the principal factors influencing puberty. The age at onset of the reproductive activity in the sheep is different among the various breeds. In the Sarda lambs the age of the onset of puberty is about 7-8 months. However the animals that have this age don’t reach the puberty if photoperiod and body weight are not suitable. Both the female lambs born in October-November and in February reach puberty in the same subsequent autumn breeding season. This reproductive behaviour evidences that photoperiod plays an important role in the onset of puberty (Papachristoforou et al., 2000).The female lambs born in later spring uneasily reach puberty within the subsequent breeding season, although photoperiod is favourable. This retard in the onset of reproductive activity is due to the attainment of the body maturity only during subsequent long day period but they reach reproductive activity only during the autumn of the subsequent year (Foster et al., 1985). In fact, some authors suggested that besides photoperiod and age, attainment of the 60% of adult weight is essential for onset of puberty (Abecia et al., 2001). Indeed the undernourished animals delay puberty, in comparison to well nourished subjects (I’Anson et al., 1997). This behaviour is linked to the different LH pulse frequency: restricted diet lambs show one pulse per 4 hours, instead fed ad libitum subjects manifest four or five pulse per 4 hours (Ebling et al., 1990). The purpose of this investigation is to determine the onset of puberty and to research its linkage with body weight in Sarda female lambs during breeding season under natural condition

Advantages of GPU-accelerated approach for solving the Parker equation in the heliosphere

The increasing of experimental observations' accuracy and model complexity requires the development of a new class of numerical solvers. In this work, we present a GPU-accelerated approach for solving the Parker equation in the heliosphere using a stochastic differential equation (SDE) approach. The presented method was applied to a generic system of SDE using the CUDA programming language. Our approach achieves significant speedup compared to a CPU implementation, allowing us to efficiently solve for the modulated spectra of charged particles in the heliosphere. We demonstrate the accuracy and efficiency of our method through numerical experiments on a realistic model of the heliosphere

Genetic diversity of <i>NRAMP1</i> 3'-UTR microsatellite in cattle breeds reared in Sardinia

The aim of this study was to compare the allele frequency of 3'-UTR NRAMP1 (Natural Resistance-Associated Macrophage Protein) microsatellite between local and specialized dairy cattle breeds reared in Sardinia, Italy. Blood samples were collected and DNA was extracted from 97 Sarda, 55 Italian Brown and 36 Italian Friesian cattle and analysed by means of PCR and PCR-SSCP. On the whole, three alleles were found, GT13, GT14, and GT15. GT13 showed the highest frequency in all the breeds: 0.874 in the Sarda, 0.973 in the Italian Brown and 1 in the Italian Friesian. For the Sarda, both GT14 and GT15 showed a frequency of 0.063, while for the Italian Brown 0.018 and 0.009, respectively. Homozygous GT13/GT13 was the unique genotype for the Italian Friesian and the most representative for the Italian Brown (0.964) and Sarda (0.823). The other genotypes for the Sarda were: GT14/GT14 (0.042), GT13/GT14 (0.010), GT13/GT15 (0.094) and GT14/GT15 (0.031); as regards the Italian Brown, both GT14/GT14 and GT13/GT15 showed a genotypic frequency of 0.018. The observed heterozygosity was lower than the expected value both for the Sarda and the Italian Brown. Sarda showed a higher genetic variability than Italian Brown and Italian Friesian

PCR-SSCP analysis of GH gene in Sarda goats: a high variability and its preliminary effects on dairy performances

The growth hormone (GH) gene can be utilized as a major gene because in various domestic livestock its polymorphisms have been associated to milk traits. The aim of this research was to investigate single-strand conformation polymorphism (SSCP) in the exon 3 of gGH (goat GH) gene and to evaluate the possible association with milk traits in Sarda goat breed. Forty-four primiparous lactating goats were randomly chosen, and the productive parameters (milk yield, fat, protein, and lactose percentage) of three consecutive lactations were monitored. The exon 3 of the gGH gene was PCR amplified and the resulting products were analysed by SSCP. Six conformational patterns were detected. The sequencing of SSCP patterns revealed the occurrence of six nucleotide changes, two of which determined amino acid changes in the deduced protein sequence. A preliminary comparative analysis of the productive traits related to three lactations with the genomic profiles derived from the SSCP analysis was performed with the ANOVA statistical method. SSCP polymorphic patterns in exon 3 were associated (P<0.01) with milk yield, fat and protein percentages, and with lactose content (P<0.05). These findings may be used for marker assisted selection in Sarda goat, in order to improve dairy production, preserving genetic diversity of the population

Milk yield, quality, and coagulation properties of 6 breeds of goats: Environmental and individual variability.

ABSTRACT 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

Effect of composition on coagulation, curd firming, and syneresis of goat milk.

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

Relationship between milk urea, blood plasma urea and body condition score in primiparous browsing goats with different milk yield level

Abstract. The aim of this study was to investigate the relationships among milk urea, blood plasma urea, milk yield and body condition score (BCS) in primiparous goats fed at pasture. Ninety goats of Sarda breed were used and, on the basis of their yield level, divided in three groups of 30 animals each, low (LY), intermediate (IY) and high milk yield (HY). Daily milk yield, milk protein content, milk urea, plasma total protein and albumin, plasma urea and BCS were measured at monthly intervals from 45 days in milking (45 DIM) to 165 DIM. Milk yield level affected protein concentration of milk and plasma, whereas albumin showed no variation. Plasma and milk urea showed a high correlation (P<0.001) despite of the yield level; plasma urea was always lower than milk urea. BCS decreased on 75 DIM and again after 135 DIM, and it was not affected by the milk yield level. Because milk urea and plasma urea were closely correlated and not influenced by the yield level, the study pointed out that measurement of milk urea could be utilized to evaluate urea metabolism also for browsing goats