Genome-wide homozygosity in Maremmana Cattle

The current availability of large numbers of single nucleotide polymorphisms (SNPs) throughout the genome makes these markers particularly suitable for the detection of patterns of genetic diversity and of genome-wide homozygosity in animal populations. The aim of this work was to estimate genetic diversity and homozygosity in the Maremmana cattle breed. We used a sample of 149 animals (males and females) genotyped with the BovineSNP50 v2 (54K) Illumina BeadChip. After editing for call-rate >0.9 and removing SNP unassigned or on the sex chromosomes, 128 animals and 50,814 SNPs were left. We estimated the following genetic parameters: observed and expected heterozygosity (Ho and He), minor allele frequency (MAF), and the FIS statistic. We also scanned the genome for runs of homozygosity (ROH). In the present study, ROH were detected based on 20-SNP-long sliding-windows, and allowing for a maximum of 1 missing and 1 heterozygote genotype, and a maximum gap between consecutive SNP of 105 bp. ROH contained minimum 10 SNPs, and had a minimum length of 1 Mb and a minimum density of 1 SNP every 50 kbps. The average Ho and He were 0.374 ± 0.132 and 0.365 ± 0.120, respectively, and the average MAF was 0.274 ± 0.130. These values are consistent with the range observed in other cattle breeds. We obtained some negative values for FIS (-0.162 to 0.180) which corresponded to animals with lower than average homozygosity. In total, 10,465 ROH were detected (81.75 per animal), with an average length of 2.69 Mb. Most ROH (74%) had length 2 Mb. ROH are contiguous lengths of homozygous genomic segments where the two inherited haplotypes are identical. ROH indicate genomic regions where a reduction in heterozygosity occurred, and offer new opportunities to estimate inbreeding (F). The inbreeding coefficient based on ROH (FROH) was estimated by the ratio between the total ROH length and the size of the genome in each animal. Average FROH was 0.0869 ± 0.032. Unlike inbreeding estimated based on Ho, FROH is not influenced by allele frequencies (sampling) and can distinguish recent from ancient inbreeding. However, FROH requires SNP positions to be known (unlike Ho). Two genomic regions with ROH in over 60% of the animals were found: one on BTA6 (38.6-39.7 Mbps), one on BTA13 (54.3-54.8 Mbps). These may highlight regions where selective pressures have shaped the genome of the Maremmana breed

Assessment of Poly(ADP-ribose) Polymerase1 (PARP1) expression and activity in cells purified from blood and milk of dairy cattle

Poly(ADP-ribosyl)ation (PAR) is a post-translational protein modification catalysed by enzyme member of the poly(ADP-ribose) polymerases (PARPs) family. The activation of several PARPs is triggered by DNA strand breakage and the main PARP enzyme involved in this process is PARP1. Besides its involvement in DNA repair, PARP1 is involved in several cellular processes including transcription, epigenetics, chromatin re-modelling as well as in the maintenance of genomic stability. Moreover, several studies in human and animal models showed PARP1 activation in various inflammatory disorders. The aims of the study were (1) to characterize PARP1 expression in bovine peripheral blood mononuclear cells (PBMC) and (2) to evaluate PAR levels as a potential inflammatory marker in cells isolated from blood and milk samples following different types of infection, including mastitis. Our results show that (i) bovine PBMC express PARP1; (ii) lymphocytes exhibit higher expression of PARP1 than monocytes; (iii) PARP1 and PAR levels were higher in circulating PBMCs of infected cows; (iv) PAR levels were higher in cells isolated from milk with higher Somatic Cell Counts (SCC > 100,000 cells/mL) than in cells from milk with low SCCs. In conclusion, these findings suggest that PARP1 is activated during mastitis, which may prove to be a useful biomarker of mastitis

Transcriptomic analysis of two sheep breeds during lactation, using a new custom microarray platform

We aim at understanding the genomic influence on milk quality and synthesis by comparing two sheep breeds using sheep-specific microarray technology. From sheep ESTs deposited at NCBI we generated a chip carrying about 22,000 non-redundant features in quadruplicate, achieving very good technical outcomes. Oligos were in situ generated on chip using the Combimatrix equipment. We analysed the mammary transcriptome in individuals of two sheep breeds at two lactation stages, to identify genes controlling milk production and metabolic pathways in which these genes are involved. With |FC|>1.4, and p-value≤0.05, 142 and 14 genes resulted differentially expressed in stages 01 and 02, respectively

Association analyses of single nucleotide polymorphisms in the <i>leptin</i> and <i>leptin receptor</i> genes on milk and morphological traits in Holstein cows

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Genome-wide association for milk production and lactation curve parameters in Holstein dairy cows

The aim of this study was to identify genomic regions associated with 305-day milk yield and lactation curve parameters on primiparous (n = 9,910) and multiparous (n = 11,158) Holstein cows. The SNP solutions were estimated using a weighted single-step genomic BLUP approach and imputed high-density panel (777k) genotypes. The proportion of genetic variance explained by windows of 50 consecutive SNP (with an average of 165 Kb) was calculated, and regions that accounted for more than 0.50% of the variance were used to search for candidate genes. Estimated heritabilities were 0.37, 0.34, 0.17, 0.12, 0.30 and 0.19, respectively, for 305-day milk yield, peak yield, peak time, ramp, scale and decay for primiparous cows. Genetic correlations of 305-day milk yield with peak yield, peak time, ramp, scale and decay in primiparous cows were 0.99, 0.63, 0.20, 0.97 and -0.52, respectively. The results identified three windows on BTA14 associated with 305-day milk yield and the parameters of lactation curve in primi- and multiparous cows. Previously proposed candidate genes for milk yield supported by this work include GRINA, CYHR1, FOXH1, TONSL, PPP1R16A, ARHGAP39, MAF1, OPLAH and MROH1, whereas newly identified candidate genes are MIR2308, ZNF7, ZNF34, SLURP1, MAFA and KIFC2 (BTA14). The protein lipidation biological process term, which plays a key role in controlling protein localization and function, was identified as the most important term enriched by the identified genes

Expert-based development of a generic HACCP-based risk management system to prevent critical negative energy balance in dairy herds

The objective of this study was to develop a generic risk management system based on the Hazard Analysis and Critical Control Point (HACCP) principles for the prevention of critical negative energy balance (NEB) in dairy herds using an expert panel approach. In addition, we discuss the advantages and limitations of the system in terms of implementation in the individual dairy herd. For the expert panel, we invited 30 researchers and advisors with expertise in the field of dairy cow feeding and/or health management from eight European regions. They were invited to a Delphi-based set-up that included three inter-correlated questionnaires in which they were asked to suggest risk factors for critical NEB and to score these based on 'effect' and 'probability'. Finally, the experts were asked to suggest critical control points (CCPs) specified by alarm values, monitoring frequency and corrective actions related to the most relevant risk factors in an operational farm setting. A total of 12 experts (40 %) completed all three questionnaires. Of these 12 experts, seven were researchers and five were advisors and in total they represented seven out of the eight European regions addressed in the questionnaire study. When asking for suggestions on risk factors and CCPs, these were formulated as 'open questions', and the experts' suggestions were numerous and overlapping. The suggestions were merged via a process of linguistic editing in order to eliminate doublets. The editing process revealed that the experts provided a total of 34 CCPs for the 11 risk factors they scored as most important. The consensus among experts was relatively high when scoring the most important risk factors, while there were more diverse suggestions of CCPs with specification of alarm values and corrective actions. We therefore concluded that the expert panel approach only partly succeeded in developing a generic HACCP for critical NEB in dairy cows. We recommend that the output of this paper is used to inform key areas for implementation on the individual dairy farm by local farm teams including farmers and their advisors, who together can conduct herd-specific risk factor profiling, organise the ongoing monitoring of herd-specific CCPs, as well as implement corrective actions when CCP alarm values are exceeded

Analysis of the genetic diversity between Gentile di Puglia, Sopravissana and Sarda sheep breeds using microsatellite markers

Two Italian sheep breeds &ndash; Gentile di Puglia and Sopravissana &ndash; have undergone a consistent decline in numbers and have been widely substituted by the Sarda breed, which gives higher milk yield. With the aim to provide a basis for con- servation decisions, the genetic variability of the three breeds was investigated in this study. DNA of 60 animals was PCR amplified at the following microsatellite loci: CSSM43, CSSM47, CSSM60, TGLA110, TGLA122, TGLA126, TGLA377, ETH3, ETH10, ETH225, NRAMP1, OARCP20 and SPS115. Allele frequencies, gene diversity and genetic distances were calculat- ed. The highest differences in allele frequencies were found at the following loci: TGLA377, TGLA122, NRAMP1, OARCP20 and ETH3, while at the other loci the most frequent alleles were the same. The average inbreeding rate was 0.156 in the Gentile di Puglia, 0.158 in the Sopravissana and 0.137 in the Sarda. Average gene diversity of the analysed microsatel- lites was 0.59. Genetic distance between Gentile di Puglia and Sopravissana (0.081) indicates moderate differentiation; distances between the Sarda and the endangered breeds &ndash; 0.111 from the Gentile di Puglia and 0.107 from the Sopravissana - indicate a medium-high differentiation rate. The disappearance of the two less productive breeds would entail a consistent loss of genetic diversity. The inbreeding values are low enough to allow the implementation of sound conservation programmes