Effect of calving age on genetic evaluation of milk yield in Holstein cattle.

The aim of this study was to evaluate the effect of including calving age (CA) on genetic evaluation models for Holstein cattle. The evaluated models included the permanent environment, the sire-herd interactions, and the animals and residual effects as random. The fixed effects included the average production of milk, fat, and protein and the herd-year-season effect. The analyzed data included 603,521 records of milk production (in kg) corresponding to 438,098 animals from 527 herds. Additionally, there were 179,122 records of fat and protein components, corresponding to 148,930 animals from 137 herds. The records were classified by first lactation only (FL) and all available lactations (AL) for validation test (VT). The FL records corresponded to 275,487 milk production records with a mean of 10,874.1 ± 2773.9 kg at a mean CA of 25.6 ± 4.2 months. For FL, the milk components consisted of 78,955 records with a mean fat production of 392.86 ± 89.9 kg, a mean protein production of 362.8 ± 74.9 kg and a mean CA of 25.2 ± 4.1 months. For AL, the number of records was 603,521 for milk production with a mean of 10,802.8 ± 2905.9 kg and a mean CA of 35.6 ± 11.5 months. For the milk components, there were 179,122 records with a mean of 36.1 ± 9.5 months for CA and 388.3 ± 98.4 kg and 356.7 ± 82.6 kg for fat and protein, respectively. Three models were compared: the base model (M0) described above, and two alternative models that included CA in a linear and quadratic form (M1 and M2, respectively). Estimations of the variance components (VC) and breeding value (BV) were obtained using a repeatability animal model, with the same phenotypic and pedigree information used for all models. To select the best fit model for the data, a likelihood ratio test (LRtest) was used. A validation test (VT) was also applied to each model to evaluate the consistency of the genetic trends for females with information on AL and FL. The inclusion of CA in its linear form (M1) was the model that achieved the best results in the LRtest and an acceptable value for the VT. These results show that CA improves the model fit for BV prediction and reliability.

Genome-Wide Association Studies for Methane Production in Dairy Cattle.

Genomic selection has been proposed for the mitigation of methane (CH4) emissions by cattle because there is considerable variability in CH4 emissions between individuals fed on the same diet. The genome-wide association study (GWAS) represents an important tool for the detection of candidate genes, haplotypes or single nucleotide polymorphisms (SNP) markers related to characteristics of economic interest. The present study included information for 280 cows in three dairy production systems in Mexico: 1) Dual Purpose (n = 100), 2) Specialized Tropical Dairy (n = 76), 3) Familiar Production System (n = 104). Concentrations of CH4 in a breath of individual cows at the time of milking (MEIm) were estimated through a system of infrared sensors. After quality control analyses, 21,958 SNPs were included. Associations of markers were made using a linear regression model, corrected with principal component analyses. In total, 46 SNPs were identified as significant for CH4 production. Several SNPs associated with CH4 production were found at regions previously described for quantitative trait loci of composition characteristics of meat, milk fatty acids and characteristics related to feed intake. It was concluded that the SNPs identified could be used in genomic selection programs in developing countries and combined with other datasets for global selection.

Pedigree verification and parentage assignment using genomic information in the Mexican Holstein population.

Genealogical information is an essential tool for carrying out any genetic improvement program. The objective of this study was to determine the accuracy of pedigree information in the Mexican registered Holstein population using genomic data available in Mexico and for the US Holstein population. The study included 7,508 animals (158 sires and 7,350 cows) that were born from 2002 through 2014, registered with Holstein de México, and genotyped with single nucleotide polymorphism arrays of different densities. Parentage could not be validated for 17% of sires of cows and 12% of sires of bulls. Most (79%) of the dams of cows and the dams of bulls had no genotype available and could not be validated. A parentage test was possible for only 6,104 sires of cows, 139 sires of bulls, 1,519 dams of cows, and 33 dams of bulls. Of the animals with a parentage test, parent assignment was confirmed for 89% of sires of cows, 92% of dams of cows, 95% of sires of bulls, and 97% of dams of bulls. Parent discovery was possible for some animals without confirmed parents: 17% for sires of cows, 2.5% for dams of cows, 43% for sires of bulls, and 0% for dams of bulls. Of the 7,795 progeny tests, 777 had parent conflicts, which is an error rate of 9.97% for parental recording in the population, a rate that is similar to those recently reported for other populations. True parents for some progeny conflicts (15%) were discovered for the Mexican population, and the remaining parents were assigned as unknown. Expected effects of misidentification on rate of genetic gain could be decreased by half if genealogical errors were decreased to 5%. This study indicates that genotyping and genealogy recovery may help in increasing rates of genetic improvement in the Mexican registered Holstein population.

Digestibility of Quinoa (Chenopodium quinoa Willd.) Protein Concentrate and Its Potential to Inhibit Lipid Peroxidation in the Zebrafish Larvae Model.

Quinoa protein concentrate (QPC) was extracted and digested under in vitro gastrointestinal conditions. The protein content of QPC was in the range between 52.40 and 65.01% depending on the assay used. Quinoa proteins were almost completely hydrolyzed by pepsin at pH of 1.2, 2.0, and 3.2. At high pH, only partial hydrolysis was observed. During the duodenal phase, no intact proteins were visible, indicating their susceptibility to the in vitro simulated digestive conditions. Zebrafish larvae model was used to evaluate the in vivo ability of gastrointestinal digests to inhibit lipid peroxidation. Gastric digestion at pH 1.2 showed the highest lipid peroxidation inhibition percentage (75.15%). The lipid peroxidation activity increased after the duodenal phase. The digest obtained at the end of the digestive process showed an inhibition percentage of 82.10%, comparable to that showed when using BHT as positive control (87.13%).

Effectiveness of surgery in liver metastasis from colorectal cancer: experience and results of a continuous improvement process.

PURPOSE: The aim of this study was to estimate the effectiveness of surgery in liver metastasis from colorectal cancer. METHODS: We conducted a prospective and observational study of patients with colorectal liver metastasis operated on at the San Cecilio University Hospital of Granada from March 2003 until June 2013. The primary variables of the result were survival and morbidity before 30 days of the post-operative period. We also measured preoperative and surgical variables. RESULTS: A total of 147 patients with liver metastasis of colorectal origin underwent surgical removal during the period of study, 38 of whom had repeat surgery. 34 had a second resection, 3 had a third one and one only patient had a fourth one, for a total of 185 registered operations. The global 5-year survival rate was 38 and 17 % after 10 years. There were 115 patients who had neither radiofrequency nor exploratory laparotomy, 38 % of them survived over 60 months. The average disease-free time was 23.6 months ± 47.3, with significant differences observed between types of procedures. Patients that were operated on just once (n = 25) had a five-year actuarial survival rate of 35 %, a morbidity rate of 24 % and a mortality rate of 0.6 % (1 patient only). The average hospital stay was 13.8 days and the disease-free time was 15.8 months. CONCLUSION: The results obtained in our surgical unit in terms of morbidity, mortality and five-year actuarial survival rates are comparable to those of other units at large institutions, which are currently considered the standards of quality.

Effect of reference population size and available ancestor genotypes on imputation of Mexican Holstein genotypes.

The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNP) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local population of 2,011 genotyped Mexican Holsteins, (2) animals in scenario 1 plus 866 Holsteins in the US genotype database (GDB) with genotyped Mexican daughters, and (3) animals in scenario 1 and all US GDB Holsteins (338,073). Genotypes from 4 chip densities (2 low density, 1 mid density, and 1 high density) were imputed using findhap (version 3) to the 45,195 markers on the mid-density chip. Imputation success was determined by comparing the numbers of SNP with 1 or 2 alleles missing and the numbers of differently predicted SNP (conflicts) among the 3 scenarios. Imputation accuracy improved as chip density and numbers of genotyped ancestors increased, and the percentage of SNP with 1 missing allele was greater than that for 2 missing alleles for all scenarios. The largest numbers of conflicts were found between scenarios 1 and 3. The inclusion of information from direct ancestors (dam or sire) with US GDB genotypes in the imputation of Mexican Holstein genotypes increased imputation accuracy by 1 percentage point for low-density genotypes and by 0.5 percentage points for high-density genotypes, which was about half the gain found with information from all US GDB Holsteins. A larger reference population and the availability of genotyped ancestors improved imputation; animals with genotyped parents in a large reference population had higher imputation accuracy than those with no or few genotyped relatives in a small reference population. For small local populations, including genotypes from other related populations can aid in improving imputation accuracy.

Antibacterial activity of hen egg white lysozyme modified by heat and enzymatic treatments against oenological lactic acid bacteria and acetic acid bacteria.

The antimicrobial activity of heat-denatured and hydrolyzed hen egg white lysozyme against oenological lactic acid and acetic acid bacteria was investigated. The lysozyme was denatured by heating, and native and heat-denatured lysozymes were hydrolyzed by pepsin. The lytic activity against Micrococcus lysodeikticus of heat-denatured lysozyme decreased with the temperature of the heat treatment, whereas the hydrolyzed lysozyme had no enzymatic activity. Heat-denatured and hydrolyzed lysozyme preparations showed antimicrobial activity against acetic acid bacteria. Lysozyme heated at 90°C exerted potent activity against Acetobacter aceti CIAL-106 and Gluconobacter oxydans CIAL-107 with concentrations required to obtain 50% inhibition of growth (IC50) of 0.089 and 0.013 mg/ml, respectively. This preparation also demonstrated activity against Lactobacillus casei CIAL-52 and Oenococcus oeni CIAL-91 (IC50, 1.37 and 0.45 mg/ml, respectively). The two hydrolysates from native and heat-denatured lysozyme were active against O. oeni CIAL-96 (IC50, 2.77 and 0.3 mg/ml, respectively). The results obtained suggest that thermal and enzymatic treatments increase the antibacterial spectrum of hen egg white lysozyme in relation to oenological microorganisms.