Genetic analysis of heat stress effects on yield traits, udder health, and fatty acids of Walloon Holstein cows

Genetic parameters that considered tolerance for heat stress were estimated for production, udder health, and milk composition traits. Data included 202,733 test-day records for milk, fat, and protein yields, fat and protein percentages, somatic cell score (SCS), 10 individual milk fatty acids (FA) predicted by mid-infrared spectrometry, and 7 FA groups. Data were from 34,468 first-lactation Holstein cows in 862 herds in the Walloon region of Belgium and were collected between 2007 and 2010. Test-day records were merged with daily temperature-humidity index (THI) values based on meteorological records from public weather stations. The maximum distance between each farm and its corresponding weather station was 21km. Linear reaction norm models were used to estimate the intercept and slope responses of 23 traits to increasing THI values. Most yield and FA traits had phenotypic and genetic declines as THI increased, whereas SCS, C18:0, C18:1 cis-9, and 4 FA groups (unsaturated FA, monounsaturated FA, polyunsaturated FA, and long-chain FA) increased with THI. Moreover, the latter traits had the largest slope-to-intercept genetic variance ratios, which indicate that they are more affected by heat stress at high THI levels. Estimates of genetic correlations within trait between cold and hot environments were generally high (>0.80). However, lower estimates (<=0.67) were found for SCS, fat yield, and C18:1 cis-9, indicating that animals with the highest genetic merit for those traits in cold environments do not necessarily have the highest genetic merit for the same traits in hot environments. Among all traits, C18:1 cis-9 was the most sensitive to heat stress. As this trait is known to reflect body reserve mobilization, using its variations under hot conditions could be a very affordable milk biomarker of heat stress for dairy cattle expressing the equilibrium between intake and mobilization under warm conditions.

Genetic diversity and joint-pedigree analysis of two importing Holstein populations

Genetic diversity and relatedness between 2 geographically distant Holstein populations (in Luxembourg and Tunisia) were studied by pedigree analysis. These 2 populations have similar sizes and structures and are essentially importing populations. Edited pedigrees included 140,392 and 151,381 animals for Tunisia and Luxembourg, respectively. To partially account for pedigree completeness levels, a modified algorithm was used to compute inbreeding. The effective numbers of ancestors were derived from probabilities of gene origin for the 2 populations of cows born between 1990 and 2000. The 10 ancestors with the highest contributions to genetic diversity in the cow populations accounted for more than 32% of the genes. Eight of these 10 ancestors were the same in both populations. The rates of inbreeding were different in the 2 populations but were generally comparable to those found in the literature for the Holstein breed. Average inbreeding coefficients per year, estimated from the data, ranged from 0.91 and 0.50 in 1990 to 3.10 and 2.12 in 2000 for the Tunisian and Luxembourg populations, respectively. Genetic links have also strengthened with time. Average additive relationships between the 2 populations were as high as 2.2% in 2000. Results suggest that it would be possible to investigate genotype by environment interactions for milk traits using the Tunisian and Luxembourg dairy populations.

Predictability of bull merit from genetic evaluations of sires and maternal grandsires using an animal model

The ability of animal model evaluations to predict the genetic potential of a bull from his sire and maternal grandsire was investigated. Theoretical coefficients were derived for different combinations of progeny records on the bull, sire, and maternal grandsire. Coefficients > 0.50 for sires and > 0.25 for maternal grandsires were associated with bulls with few daughters. Ten animal model evaluations of Holsteins, July 1989 to January 1994, were used to estimate coefficients realized in three populations: 1) all AI bulls (n = 6924), 2) current AI bulls (n = 1344), and 3) elite AI bulls (n = 6116). The PTA were analyzed for milk, fat, and protein yields, and for fat and protein percentages. Birth year of sons nested within the birth year of their sire was included as a random effect with a first-order autoregressive process for the regression model used to estimate the realized coefficients for sires and maternal grandsires. After adjustment for the genetic trend for estimates of sires, the correlation coefficient between predicted merit of sons from 2 consecutive yr ranged from 0.34 to 0.87. The PTA of bulls from first-crop evaluation were accurately predicted from PTA of sire and maternal grandsire for yield and percentage traits.

Kappa casein gene polymorphism in local Tunisian goats

The genetic polymorphism of the goat Kappa casein was investigated in Tunisian goats. Blood samples were collected from local goat breeds. Samples of genomic DNA were obtained from leukocytes of 175 dairy goats and regions of interest in the gene were amplified by Polymerase Chain Reaction (PCR) and then evaluated in agarose gel. For a better characterization of the single nucleotide polymorphism, a PCR-Restriction Fragment Length Polymorphism was performed employing the endonuclease DNA amplification using 459 bp primers. The PCR products of primers (459 bp) digested by restriction enzyme Alw44I produced two fragments of 459 and 381 bp. The Kappa casein allelic variants in tested animals revealed different genotypes, two of them were homozygous: AA or BB, AC or BC and CC. Genotypic frequencies were 12.5, 60.5 and 27% for AA or BB, CC and AC or BC, respectively. Identification of different variants of the Kappa casein can be used for the improvement and conservation of Tunisian local goats.

[Massive intraatrial mass?]

Posterior mediastinal hematoma in a rare and potentially lethal disease and is frequently consecutive to a traumatism. We report the original case of a 88-year-old male admitted to our department for lipothymia and syncope related to a severe compression of the left atrium by an important mediastinal hematoma mimicking in transthoracic echocardiography an obstructive intraatrial mass.

P857 Diagnostic and prognostic value of 2D Strain in Non ST elevation myocardial infarction patients

Background

Following an acute coronary syndrome, ischemic myocardial dysfunction has several degrees of severity and different outcomes from a total or partial recovery to an irreversible injury.

In this study led in non-ST elevation myocardial infarction (NSTEMI) patients without otherwise previous non-ischemic cardiomyopathy (NICM), we investigated the correlation between 2D global longitudinal strain (GLS) and angiographic prognostic factors.

The ability of territorial longitudinal strain (TLS), defined as the sum of segmental strain in a coronary territory,to identify culprit artery occlusion was also assessed.

Methods

82 consecutive NSTEMI patients were prospectively screened for inclusion; 70 of them without NICM were enrolled. Severe coronary artery disease (CAD) was defined as three-vessel disease or a left main disease. Group 1 and 2 were defined by the presence or not of severe CAD. Statics ‘analyses was performed with IBM SPSS Statistics (version 22).

Results

mean age of patients was 60, 2 ±10 years. 37 patients had diabetes mellitus (53%), 31 had hypertension (44%), 21 had dyslipidemia (30%) and 5 had renal insufficiency (7%). Severe CAD was present in 24 patients (34%).

The first ultrasound exam showed that mean EF was 49 ± 11, mean WMSI was 1.43 ± 0.4 and mean GLS was -14.9 ± 4.

GLS was higher in group 1 (-12.82 ± 0.95 vs -16.04 ± 0.42; p &lt; 0.001); LVEF and WMSI in group 1 and 2 were (43.3 ± 13.5% Vs 52.7 ± 7.9%; p &lt; 0.001) and (1.64 ± 0.1 Vs 1.32 ± 0.04; p &lt; 0.001) respectively. Correlations were found between LVEF and GLS (p = 0.004), and between WMSI and GLS (p = 0.002) . TLS was able to discriminate between coronary stenosis of LAD, LCX or RCA and to predict the occlusion of the culprit vessel: 7 patients had acute coronary occlusion (10%). TLS was -7.4 ± 5.1 in patients with coronary occlusion and -14.1 ± 6 in the absence of coronary occlusion (p &lt; 0.001). A cut off of -9.5 was able to detect this occlusion with a specificity of 82% and a sensitivity of 85%.

The second ultrasound exam, performed after a median of 10 ± 3.1 months, showed a statistically significant improvement of EF (53 ± 10, p =0.02), WMSI (1.35 ± 0.39, p= 0.01) as well as GLS (-17.1 ± 4.2, p =0.004).

Patients who received only medical treatment (n = 11) had the lowest variation of EF (47% to 48 %; p = 0.7), WMSI (1.62 to 1.59; p = 0.69) and GLS (14.2 to 15.2; p = 0.2) with no statistical correlation between the two exams. While patients who had PCI or bypass revascularization, had the best outcome with improvement of EF (49% to 53%; p = 0.002), WMSI (1.4 to 1.32;p = 0.01) and GLS (15 to 17.4;p = 0.004).

Conclusion

GLS is a strong diagnostic and prognostic ultra sound parameter for NSTEMI patients correlated to CAD severity. Strain is a reliable parameter during follow up.TLS can be used to localize the culprit coronary artery and especially to predict its occlusion during the acute phase of NSTEMI which can lead to a different therapeutic strategy.