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

Genotype at the MTNR1A locus and response to melatonin treatment in Sarda lambs

With the aim to evaluate the effect of melatonin treatment and melatonin receptor 1A (MTNR1A) genotype on advance of puberty, 423 Sarda lambs were chosen. On June 26th, they were divided into three groups, each of 141 animals (groups 0, 1, and 2), on the basis of live weight. On June 30th, animals in group 1 received a single implant (18 mg melatonin), while group 2 received two implants. Group 0 was untreated. Thirty-five days after treatment (August 4th), rams were introduced and after 40 days they were removed. From January 1st to February 10th lambing dates were recorded. Genomic DNA was extracted and subjected to PCR for the amplification of exon II and then digested with enzymes MnlI and RsaI and placed into +/+, +/−, or −/− group for MnlI and C/C, C/T, or T/T group for RsaI. Samples were cloned and sequenced. Data obtained were subjected to χ2 test in order to evaluate the difference in fertility among groups and the link between genotype and reproductive activity. Genotype +/+ and C/C showed the highest incidence. Treated groups showed a higher number of lambing at 10th February compared to control group (P<0.04). Melatonin treatment results more efficient in +/+ genotype

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

Polymorphism of Caprine SLC11A1 Gene and Relationships with Hygienic Characteristics of Milk

The solute carrier family 11 member A1 (SLC11A1) gene is associated with resistance to infectious diseases. Genetic variability at the 3’ untranslated region (3’-UTR) of this gene is due to the presence of a polymorphic microsatellites that contain a (GT) n dinucleotide repeat. The microsatellite variability and relationships with milk yield and composition, somatic cell count (SCC) and total microbic count (TMC) were investigated in 260 goats of Sarda breed. Genotyping of the upstream guanine-thymine repeat (GT)n revealed twenty different genotypes and eight alleles (GT11, GT12, GT14, GT15, GT16, GT17, GT18 and GT19). The present study confirmed the high genetic variability of the Sarda goat and that the genotype of the microsatellite at 3’-UTR SLC11A1 affected many chemical and hygienic characteristics of milk as fat, protein and SCC

Polymorphism of Caprine SLC11A1 Gene and Relationships with Hygienic Characteristics of Milk

The solute carrier family 11 member A1 (SLC11A1) gene is associated with resistance to infectious diseases. Genetic variability at the 3’ untranslated region (3’-UTR) of this gene is due to the presence of a polymorphic microsatellites that contain a (GT) n dinucleotide repeat. The microsatellite variability and relationships with milk yield and composition, somatic cell count (SCC) and total microbic count (TMC) were investigated in 260 goats of Sarda breed. Genotyping of the upstream guanine-thymine repeat (GT)n revealed twenty different genotypes and eight alleles (GT11, GT12, GT14, GT15, GT16, GT17, GT18 and GT19). The present study confirmed the high genetic variability of the Sarda goat and that the genotype of the microsatellite at 3’-UTR SLC11A1 affected many chemical and hygienic characteristics of milk as fat, protein and SCC

Reproductive activity in sheep with different lambing period treated with melatonin in April

The object was to evaluate the effect of melatonin treatment on the advance in April of the reproductive resumption in Sarda breed sheep with different lambing period. For the research two farms, located in North Sardinia between 39° and 40° N, were chosen. In each farm, 120 lactating ewes were selected: 30 lambed between October 20th and November 20th (group 1); 30 lambed between December 1st and 30th (group 2); 30 lambed between January 1st and 30th; 30 lambed between February 1st and 28th (group 4). In each farm, each group of 30 animals was divided into two subgroups of 15 animals (M and C). On April 1st, in each farm, the animals of the M subgroups were treated with a implant containing 18 mg melatonin. The subgroups C were kept as control. The lambing dates and the number of newborn lambs were recorded until 220 days after ram introduction. In treated animals greatest fertility (P<0.01) and lowest distance in days from male introduction to lambing (P<0.01) were recorded. The best reproductive performances were found in the group 1 and 2 compared to the other two groups (P<0.01).The present research shows that melatonin treatment should be made 3 or 4 months after lambing, in order to obtain optimal results

Polymorphism of the MTNR1A Melatonin Receptor Gene in Goat Breeds of Northern Italy

Melatonin receptor MT1, encoded by the MTNR1A gene, is the main one involved in the seasonal regulation of reproductive activity. A correlation between this gene polymorphism and reproductive performance has been demonstrated in sheep. To date, no data about MTNR1A gene polymorphism are available regarding Italian goat breeds other than the Sarda goat. This study aimed to detect any PCR-RFLP polymorphic sites of MTNR1A using MnlI and RsaI enzymes in Northern Italian goat breeds, which are characterized by a pronounced reproductive seasonality. One-hundred-eight adult female goats belonging to four different breeds were included in the study (i.e., Frisa Valtellinese, n = 29; Orobica, n = 23; Lariana, n = 29; Camosciata delle Alpi, n = 27). Blood was sampled from each goat. Genomic DNA was extracted from each sample and the main part of exon II of MTNR1A gene was amplified by PCR and digested with MnlI and RsaI enzymes. Unexpectedly, none of the fragments were found to be polymorphic. The absence of polymorphism may be linked to the macro group of goat breeds that evolved during human migrations. Breeds of the Alpine-European strain would appear to show no polymorphism, as confirmed by our study, whereas breeds belonging to the Mediterranean-African or Asian-Middle Eastern strains do

Polymorphisms of the melatonin receptor 1A (MTNR1A) gene affect the sexual performance of Rasa Aragonesa rams without changing their social dominance

This study aimed to investigate whether a specific genotype of the MTNR1A gene influences social dominance and reproductive performance in rams. Thirty-one rams were genotyped for Rsal and Mnll polymorphism of the gene: CC (n=19), CT (n=5), and TT (n=7), and GG (n=20), GA (n=6), or AA (n=5), respectively. Maintenance (standing still, lying down, drinking, feeding, walking, or stereotyping) and social behavior (agonistic and antagonistic interactions among rams) were recorded by direct observations involving instantaneous scan sampling and continuous behavior sampling. For each animal, his Index of Success (IS) and Displacement (ID) were calculated. One week after the social-behavioral observations, rams were tested in individual serving-capacity tests involving three ewes that were synchronized into estrus in a 15-m2 pen for 20 min. The genotypes did not differ in the number of aggressions they performed (CC: 88.95±12.85; CT: 106.20±21.00; TT: 70.43±8.50; GG: 76.05±8.72; GA: 119.00±16.16; AA: 95.80±36.39) or received (CC:75.79±5.82; CT:92.40±8.68; TT: 86.14±15.05; GG: 79.25±6.58; GA: 86.83±11.51; AA: 79.80±12.74), and their active and passive behaviors were similar. The genotypes did not differ significantly in IS or ID, and the proportion of rams in each success category was similar among groups. For the Rsal and Mnll polymorphism, TT and GG rams were responsible for 54% and 56% of recorded sexual events (P < 0.05), respectively. Results of this study confirm that the best sexual performance of rams was among those that carried certain genotypes of the MTNR1A gene. Still, it was not correlated with differences in social dominance