Single-step genomic evaluation for growth traits in a Mexican Braunvieh cattle population.

OBJECTIVE: The objective was to compare (pedigree-based) best linear unbiased prediction (BLUP), genomic BLUP (GBLUP), and single-step GBLUP (ssGBLUP) methods for genomic evaluation of growth traits in a Mexican Braunvieh cattle population. METHODS: Birth (BW), weaning (WW), and yearling weight (YW) data of a Mexican Braunvieh cattle population were analyzed with BLUP, GBLUP, and ssGBLUP methods. These methods are differentiated by the additive genetic relationship matrix included in the model and the animals under evaluation. The predictive ability of the model was evaluated using random partitions of the data in training and testing sets, consistently predicting about 20% of genotyped animals on all occasions. For each partition, the Pearson correlation coefficient between adjusted phenotypes for fixed effects and non-genetic random effects and the estimated breeding values (EBV) were computed. RESULTS: The random contemporary group (CG) effect explained about 50%, 45%, and 35% of the phenotypic variance in BW, WW, and YW, respectively. For the three methods, the CG effect explained the highest proportion of the phenotypic variances (except for YW-GBLUP). The heritability estimate obtained with GBLUP was the lowest for BW, while the highest heritability was obtained with BLUP. For WW, the highest heritability estimate was obtained with BLUP, the estimates obtained with GBLUP and ssGBLUP were similar. For YW, the heritability estimates obtained with GBLUP and BLUP were similar, and the lowest heritability was obtained with ssGBLUP. Pearson correlation coefficients between adjusted phenotypes for non-genetic effects and EBVs were the highest for BLUP, followed by ssBLUP and GBLUP. CONCLUSION: The successful implementation of genetic evaluations that include genotyped and non-genotyped animals in our study indicate a promising method for use in genetic improvement programs of Braunvieh cattle. Our findings showed that simultaneous evaluation of genotyped and non-genotyped animals improved prediction accuracy for growth traits even with a limited number of genotyped animals.

In vitro embryo production from ewes at different physiological stages.

BACKGROUND: The collection of ovaries from slaughterhouses is an important source of oocytes for in vitro embryo production. On the other hand, the physiological stage of slaughtered females varies and influences embryo production. OBJECTIVES: The study examined the in vitro efficiency of embryos and demi-embryos from young, non-pregnant adult, and pregnant adult ewes from a local slaughterhouse. METHODS: One thousand three hundred ovaries were collected from August to October 2020. The recovered oocytes were matured, fertilized, and cultured at 5% CO2, 38.5°C, and 100% humidity. Embryo bisection was performed in 96 blastocysts (n = 32 per treatment). The demi-embryo pairs were incubated for their reconstitution for 12 h. SAS was used for data analysis. RESULTS: The number of oocytes collected from the experimental group of non-pregnant adult ewes was higher (p ≤ 0.007) than those collected from the group of pregnant adult ewes (2.67 ± 0.19 vs. 2.18 ± 0.15 oocytes/group, respectively). The blastocyst rate was higher (p ≤ 0.0001) in the non-pregnant adult group (36.39%) than in the young (17.96%). The ratio of demi-embryos that recovered the blastocoelic cavity was higher (p < 0.05) in the young group (81.25%) than in the pregnant adult group (59.38%). The diameter of the demi-embryos was higher (p < 0.05) in the non-pregnant adult group (186.54 ± 8.70 µm) than those in the young and pregnant adult groups. CONCLUSIONS: In conclusion, the in vitro embryo production efficiency was highest when using oocytes from non-pregnant adult ewes under the conditions of this study.

Care of patients on home parenteral nutrition during the first year of the COVID-19 pandemic: Management of central line-associated bloodstream infections.

BACKGROUND AND AIM: The aim of this study was to analyze central line-associated bloodstream infections (CLABSI) in home parenteral nutrition (HPN) patients assisted by an interdisciplinary team during the first year of the COVID-19 pandemic in Argentina. METHODS: Longitudinal, retrospective and analytical study of patients on HPN for ≥90 days during 2020. Data collection included age (adults >18 years, pediatric ≤18 years), gender, diagnosis, type of catheter, number of lumens, venous access, days on HPN, infusion modality and number of CLABSI-associated events. In COVID-19 cases, number of patients, disease progression, mortality rate and microorganisms involved were analyzed. RESULTS: A total of 380 patients were included, 120 (31.6%) pediatric and 260 (68.4%) adult patients. Median age was 44.50 years (10; 62.25). Twelve patients (3.15% of the total) had COVID-19; of these, two pediatric and seven adult patients had no complications, and three adults died of COVID-19 pneumonia. The diagnoses observed were benign chronic intestinal failure (CIF, n = 311), grouped into short bowel (n = 214, 56.3%), intestinal dysmotility (n = 56, 14.7%), intestinal fistula (n = 20, 5.3%), and extensive small bowel mucosal disease (n = 21, 5.5%); malignant tumors (n = 52, 13.7%); other (n = 17, 4.4%). Total catheter days were 103,702. Median days of PN duration per patient were 366 (176.2, 366). The types of catheters used were tunneled (317 patients, 83.4%); peripherally inserted central (PICC) line (55 patients, 14.5%) and ports (8 patients; 2.1%). A total of 111 CLABSI was registered, with a prevalence of 1.09/1000 catheter days (adult, 0.86/1000 days; pediatric, 1.51/1000 days). The microorganisms identified in infectious events were Gram + bacteria (38, 34.5%); Gram-bacteria (36, 32%); mycotic (10, 9%); polymicrobial (4, 3.6%); negative culture and signs/symptoms of CLABSI (23, 20.3%). The odds ratio between pediatric and adult patients was 2.29 (1.35, 3.90). CONCLUSION: The rate of CLABSI during the COVID-19 pandemic was within the ranges reported by international scientific societies. The risk of CLABSI was higher in pediatric patients, and mortality rate in COVID-19 infected patients was higher than in the general population.

Understanding factors influencing the estimated genetic variance and the distribution of breeding values.

This study investigated the main factors influencing the genetic variance and the variance of breeding values (EBV). The first is the variance of genetic values in the base population, and the latter is the variance of genetic values in the population under evaluation. These variances are important as improper variances can lead to systematic bias. The inverse of the genetic relationship matrix (K -1) and the phenotypic variance are the main factors influencing the genetic variance and heritability (h2). These factors and h2 are also the main factors influencing the variance of EBVs. Pedigree- and genomic-based relationship matrices (A and G as K) and phenotypes on 599 wheat lines were used. Also, data were simulated, and a hybrid (genomic-pedigree) relationship matrix (H as K) and phenotypes were used. First, matrix K underwent a transformation (K* = w K + α 11' + ß I), and the responses in the mean and variation of diag(K -1) and offdiag(K -1) elements, and genetic variance in the form of h2 were recorded. Then, the original K was inverted, and matrix K -1 underwent the same transformations as K, and the responses in the h2 estimate and the variance of EBVs in the forms of correlation and regression coefficients with the EBVs estimated based on the original K -1 were recorded. In response to weighting K by w, the estimated genetic variance changed by 1/w. We found that µ(diag(K)) - µ(offdiag(K)) influences the genetic variance. As such, α did not change the genetic variance, and increasing ß increased the estimated genetic variance. Weighting K -1 by w was equivalent to weighting K by 1/w. Using the weighted K -1 together with its corresponding h2, EBVs remained unchanged, which shows the importance of using variance components that are compatible with the K -1. Increasing ß I added to K -1 increased the estimated genetic variance, and the effect of α 11' was minor. We found that larger variation of diag(K -1) and higher concentration of offdiag(K -1) around the mean (0) are responsible for lower h2 estimate and variance of EBVs.

Performance of Holstein-Friesian calves drinking desalinated water in the preweaning period

Background: High salinity of drinking water can adversely affect health and productive performance of calves during artificial rearing. Objective: To evaluate the effect of drinking water total dissolved salts (TDS) content on productive performance of Holstein-Friesian calves during artificial rearing. Methods: Twenty-nine newborn Holstein-Friesian calves weighing 39±0.94 kg at birth were randomly assigned to two treatment groups for 56 d. Treatment 1 (n=14) consisted of drinking water with 1,469±75 mg L-1 TDS, while treatment 2 (n=15) used drinking water from the same source but filtered by reverse osmosis to contain 107±31 mg L-1 TDS. Results: Water intake was numerically affected by TDS concentration, increasing 13% (p>0.08) when drinking low-TDS water (3,554 versus 3,088 ml d-1). Feed intake (dry basis) decreased 26% (500 versus 676 g d-1; p0.05) by TDS content in the drinking water. Conclusion: Desalinated water improves productive performance of Holstein-Friesian calves during artificial rearing.

Antecedentes: Una alta salinidad del agua de bebida puede afectar negativamente la salud y el comportamiento productivo de los terneros durante la crianza. Objetivo: Evaluar el efecto del contenido de sales disueltas totales (SDT) en el agua de bebida sobre el comportamiento productivo de los terneros durante la crianza artificial. Métodos: Veintinueve terneros Holstein- Friesian recién nacidos, con 39±0,94 kg de peso vivo fueron asignados aleatoriamente a dos tratamientos. El tratamiento 1 consistió de 14 terneros que bebieron agua con 1.469±75 mg L-1 de SDT; mientras que al tratamiento 2 se asignaron 15 terneros que recibieron agua de la misma fuente, pero filtrada mediante el procedimiento de ósmosis inversa y conteniendo 107±31 mg L-1 de SDT. Resultados: La concentración de SDT afectó numéricamente el consumo de agua durante los 56 días de lactancia (p>0,08), incrementándose 13% cuando los terneros bebieron agua con bajo contenido de sales (3.554 vs 3.088 ml d-1). El consumo de alimento (base seca) disminuyó 26% (500 vs 676 g d-1; p0,05). Conclusión: El agua de bebida desalinizada mejora el comportamiento productivo de terneros Holstein durante la crianza artificial.

Antecedentes: Alta salinidade da água potável pode afetar adversamente a saúde e o desempenho produtivo de bezerros durante o acasalamento. Objetivo: Avaliar o efeito do total de sais dissolvidos (TSD) na água potável sobre o comportamento dos bezerros durante a lactação. Métodos: Vinte e nove terneiros Holstein-Friesian recém-nascidos, com 39±0,94 kg de peso vivo, foram designados aleatoriamente a dois tratamentos. O tratamento 1 considerou 14 terneiros os quais beberam água com 1.469±75 mg L-1 do total de sais dissolvidos (TSD); enquanto ao tratamento 2 se designaram 15 terneiros bebendo água da mesma fonte filtrada através do procedimento de osmose inversa e contendo 107±31 mg L-1 de TSD. Resultados: O consumo de água de bezerros durante os 56 dias de lactação artificial foi ligeiramente afetado pela concentração de TDS na água potável (p>0,08) e aumentou em 13% quando os bezerros beberam água com baixo teor de sal (3.554 vs 3.088 ml d-1); o consumo de alimento sólido (base seca) diminuiu em 26% (500 vs 676 g d-1; p0,05) pelo conteúdo de TSD na água de beber. Conclusão: A dessalinização da água de beber melhora o comportamento produtivo de terneiros Holstein durante o período de lactação artificial..

Genetic diversity in reproductive traits of Braunvieh cattle determined with SNP markers.

Braunvieh is an important dual-purpose breed in the Mexican tropics. The study of its genetic diversity is key to implementing genetic improvement programs. This study was conducted to determine genetic diversity of reproductive traits in a Mexican Braunvieh beef cattle population using single nucleotide polymorphisms in candidate genes. Information from 24 genes with 52 intra-genic loci reported in literature to be associated with productive life, pregnancy rate and cow and heifer conception rate of 150 Braunvieh males and females was considered. Observed heterozygosity (Ho) revealed high genetic diversity for the studied traits, Ho = 0.42 ± 0.087, relative to that of other populations of the same breed. Cluster analyses were carried out using the Ward and K-means algorithms. These analyses revealed high genetic diversity that was observed in the biplot of non-metric multi-dimensional scaling. It was found that clustering strategy allowed visualisation of distant groups by genotype but not by favourable alleles in all the loci. We found that the genes CSNK1E, DNAH11, DSC2, IBSP and OCLN affected most of the traits in our study and they were highly informative. Therefore, they represent a potential resource for selection and crossbreeding programs of the traits studied in Braunvieh. The analyses showed that the Mexican Braunvieh population has a high level of genetic diversity, arguably due to decades-long adaptation to the Mexican tropics.

Genetic Diversity and Population Structure for Resistance and Susceptibility to Mastitis in Braunvieh Cattle.

Mastitis is a disease that causes significant economic losses, since resistance to mastitis is a difficult trait to be improved due to its multifactorial occurrence. Therefore, our objective was to characterize a Mexican Braunvieh cattle population for genetic resistance and susceptibility to mastitis. We used 66 SNP markers for 45 candidate genes in 150 animals. The average heterozygosity was 0.445 ± 0.076, a value higher than those reported for some European breeds. The inbreeding coefficient was slightly negative for resistance to subclinical (-0.058 ± 0.055) and clinical (-0.034 ± 0.076) mastitis, possibly due to low selection for the immunological candidate genes that influence these traits. The genotypic profiles for the candidate loci per K-means group were obtained, as well as the group distribution through the graphics of the principal component analysis. The genotypic profiles showed high genetic diversity among groups. Resistance to clinical mastitis had the lowest presence of the heterozygous genotypes. Although the percentage of highly inbred animals (>50%) is up to 13.3%, there are highly heterozygous groups in terms of the studied traits, a favorable indicator of the presence of genetic diversity. The results of this study constitute evidence of the genetic potential of the Mexican Braunvieh population to improve mastitis-related traits.

Allelic and genotypic frequencies for loci associated with meat quality in Mexican Braunvieh cattle.

The objective was to estimate allelic and genotypic frequencies for loci associated with meat quality in a Mexican population of Braunvieh cattle. Information was obtained from 300 animals genotyped with the Genomic Profile Bovine LD chip of 30K and 50K SNPs. After the final edition, including quality control, the data contained information for 12 loci of the CAPN1, CAPN3, CAPN5, CAPN14, DGAT1, DGAT2, TG, ANK1, and MADH3 genes. Allelic and genotypic frequencies and Hardy-Weinberg equilibrium were estimated with the Cervus 3.0.7 software. The studied population markers were in Hardy-Weinberg equilibrium, except for those associated with CAPN1, DGAT1, and MADH3. Frequencies higher than those reported for other breeds were found for genotypes associated with meat softness, higher marbling score, lower quantity of saturated fatty acids, and lower shear force (CAPN1 and DGAT2). There were similarities with frequencies reported for Bos taurus breeds for the CAPN3 and TG genes. For the DGAT1 and ANK1 genes, the frequencies of the desired genotypes were low. A marker for DGAT1 and another for MADH3 were monomorphic. The results of this study are encouraging in terms of the potential of the Braunvieh population studied for breeding programs aiming to increase meat quality. The breed has strengths that could be used either by crossbreeding to generate heterozygous animals or by selection to increase frequencies of valuable alleles.

Comparison of Microwave Short Time and Oven Heating Pretreatment on Crystallization of Raisins.

Crystalline material can develop on the surface of raisins during storage and transport, affecting the final acceptability of the product. In this work, a mild thermal pretreatment was applied to raisins to melt the pre-existing crystals and the effect of such thermal treatments on the development of crystals over a storage period was investigated. The raisins selected for this study were of the Thompson seedless variety from one Chilean company. The thermal pretreatment of raisins at 50 °C and 70 °C for 20 min in an oven and microwave (800 W) irradiation for 15 s resulted in a reduction in the percentage of crystallized raisins (w/w) from more than 50% in the control samples to less than 10% after 35 days of storage at 15 and 25 °C in a 57% relative humidity environment. The results showed that some textural parameters, such as cohesiveness and chewiness, were not affected by thermal treatment and were independent of storage temperature.

Effectiveness and optimum level of protected methionine in fattening pig diets / Efectividad y nivel óptimo de metionina protegida en dietas para cerdos en engorde / Eficácia e nível ideal de metionina protegida em dietas para suínos de engorda

Abstract Background: Methionine (Met) requirements have not been clearly established for fattening pigs due to their metabolic interrelationships and its bioavailability for protein synthesis. Objective: To determine the optimum level of regular crystalline or protected Met in pig diets from nursery to finishing. Methods: A total of 48 crossbred pigs (11.74±1.72 kg of initial body weight) were used. The treatments consisted of adding four levels (0.00, 0.05, 0.10, 0.15% in addition to dietary content) and two types of Met (regular and protected) to pig diets. Results: Nursery, Finishing I, and II pigs fed protected Met increased daily feed intake (DFI; p≤0.10). Protected Met raised daily weight gain (DWG) in nursery pigs and increased backfat thickness (BT) in nursery and grower pigs (p≤0.10). In Finishing I pigs, protected Met increased DWG and improved carcass characteristics (p≤0.10). In nursery and grower pigs, an extra 0.15% Met decreased feed:gain ratio (FGR; p≤0.10). In grower and Finishing II pigs fed extra 0.05% Met improved DWG and extra 0.10% Met reduced plasma urea concentration (p≤0.10). Conclusions: Feeding protected Met in pig diets increases DWG, DFI and BT. Increasing 0.05-0.15% Met level improves FGR, DWG, potentially reducing nitrogen excretion to the environment.

Resumen Antecedentes: los requerimientos de metionina (Met) para cerdos en crecimiento no han sido claramente establecidos, lo que se debe a sus relaciones metabólicas y su biodisponibilidad para la síntesis proteica. Objetivo: determinar el nivel óptimo de Met regular o protegida en dietas para cerdos en crecimiento. Métodos: Se utilizaron un total de 48 cerdos híbridos (11,74±1,72 kg peso vivo inicial). Los tratamientos consistieron en niveles incrementales (0,00, 0,05, 0,10, 0,15% adicionales al contenido de la dieta) y dos tipos de Met (regular y protegida) en la dieta. Resultados: los cerdos en iniciación, Finalización I, y II, alimentados con Met protegida tuvieron un mayor consumo diario de alimento (DFI; p≤0,10). La Met protegida aumentó la ganancia diaria de peso (DWG) durante la etapa de iniciación, e incrementó el grosor de la grasa dorsal (BT) en iniciación y levante (p≤0,10). Durante Finalización I, la Met protegida aumentó la DWG y mejoró las características de la canal (p≤0,10). Durante iniciación y levante, 0,15% extra de Met disminuyó la conversión alimenticia (FGR; p≤0,10). Los cerdos en levante y Finalización II alimentados con 0,05% extra de Met mejoraron la DWG y con 0.10% extra de Met redujeron la concentración de urea en plasma (p≤0,10). Conclusiones: el uso de Met protegida incrementa DWG, DFI y BT. El aumento del nivel de Met de 0,05-0,15% mejora FGR y DWG, y podria disminuir la excreción de nitrógeno al ambiente.

Resumo Antecedentes: os requisitos de metionina (Met) para suínos de engorda não foram claramente estabelecidos devido às suas relações metabólicas e sua biodisponibilidade para a síntese de proteínas. Objetivo: determinar o nível ideal de Met regular ou protegida em dietas para suínos de engorda. Métodos: foram utilizados 48 suínos híbridos (11,74±1,72 kg de peso vivo inicial). Os tratamentos consistiram em quatro níveis (0,00, 0,05, 0,10, 0,15% mais) e dois tipos (regular e protegida) de Met em dietas para suínos de engorda. Resultados: suínos no início, finalização I e II alimentados com Met protegida aumentaram o consumo diário de ração (DFI; p≤0,10). Met protegido aumentou o ganho de peso diário (DWG) em suínos na iniciação e, aumentou espessura da gordura dorsal (BT) em suínos em iniciação e crescimento (p≤0,10). Nos suínos finalização I, Met protegido aumentou DWG e melhorou as características do canal (p≤0,10). Para suínos de iniciação e crescimento, 0,15% extra de Met diminuiu conversão alimentar (FGR; p≤0,10). No crescimento e finalização II, a adição de 0,05% de Met melhoraram o DWG e com 0,10% reduziram a concentração de uréia (p≤0,10). Conclusões: o uso de Met protegida melhora DWG, DFI e BT. O nível de Met aumentado de 0,05-0,15% melhora FGR e DWG; além disso, a excreção de nitrogênio ambiental pode ser diminuída.

Impact of thermal pretreatment on crystallization of Thompson raisins.

After prolonged storage or during the shipment of raisins, a crystalline material may be developed on their surface, affecting the final acceptability of the product. The mild thermal pretreatment (50 °C for a period of 12 h and 48 h) was applied to dissolve any potential tiny crystals and nuclei already present in the raisins. The thermal pretreatment of raisins resulted in a reduction on the percentage of crystallized raisins (w/w) from more than 46% in control samples to less than 10% after 30 days of storage at 57% and 66% of relative humidity and 15 °C and 25 °C. X-ray diffraction analysis identified d-Glucose monohydrate as the main crystalline component. All the thermal treatments increased the hardness of the raisins, when they were incubated at 57% relative humidity. To mitigate the problems of crystallization of raisins during shipping, it is recommended that the raisins are thermally pretreated and the shipping conditions are controlled.

Genetic parameters for nitrogen fractions content in Mexican Brown Swiss cattle milk.

Nitrogen plays an important role in the metabolism of living organisms due to the variety of physiological functions that involve molecules that contain it. This study aimed to estimate genetic parameters for milk nitrogen fractions and the casein:protein ratio in Mexican Brown Swiss population. Milk samples from 317 cows were used to determine total (TN), non-protein (NPN), and non-casein (NCN) nitrogen. Then, crude (CP), true (TP), and whey (WP) proteins, and casein (Cas) percentages were obtained. In addition, the ratios (%) Cas:CP (CCP) and Cas:TP (CTP) were calculated. (Co)variance components and genetic parameters were estimated using an animal model. The pedigree included 2616 animals. Heritabilities were obtained from single-trait and genetic correlations from bivariate analyses. The variation among cows was large for the studied traits. Heritability estimates could be regarded as high (> 0.7) for NCN, WP, CCP, and CTP, while for the rest of the traits, the estimates were from moderate to low magnitude. Genetic correlations estimates differed in magnitude, ranging from - 0.9 to 0.9. There is enough additive genetic variability to achieve genetic improvement for the traits studied; therefore, they could be considered in a breeding program for the studied population.

Screening genetic diseases prevalence in Braunvieh cattle.

Heritable abnormalities can cause a reduction in productive performance, structural defects, or death of the animal. There are reports of hereditary abnormalities in Braunvieh cattle from several countries, but no evidence was found on their existence in Mexico. In this study, 28 genes associated with hereditary diseases were screened with the GGP-LD 30K array (GeneSeek®) in 300 Mexican registered Braunvieh animals. Allelic frequencies of the markers associated with illness were obtained for the following: citrullinaemia, spinal dysmyelination, spinal muscular atrophy, Brows Swiss fertility haplotype 2, congenital muscular dystonia, epidermolysis bullosa, Pompes, maple syrup urine, syndactyly, Weaver syndrome, crooked tail, deficiency of uridine monophosphate synthase, hypotrichosis, Marfan syndrome, and weak calf syndrome. The allelic frequency values were low for all the analysed loci (from 0.0015 to 0.0110), with exception of syndactyly (0.4145). Although homozygous animals for these genetic conditions were detected, no physical or physiological abnormalities associated with the clinical form of the diseases were observed in the sampled animals. Markers associated with a crooked tail, deficiency of uridine monophosphate synthase, hypotrichosis, Marfan syndrome, and weak calf syndrome were absent. The studied Mexican Braunvieh population does not present clinical or subclinical effects for ten diseases in homozygous animals. However, since the assessed animals are considered as breeding stock, the monitoring of carrier animals might be periodically necessary.

Potential influence of κ-casein and ß-lactoglobulin genes in genetic association studies of milk quality traits.

OBJECTIVE: From a review of published information on genetic association studies, a meta-analysis was conducted to determine the influence of the genes κ-casein (CSN3) and ß-lactoglobulin (LGB) on milk yield traits in Holstein, Jersey, Brown Swiss, and Fleckvieh. METHODS: The GLIMMIX procedure was used to analyze milk production and percentage of protein and fat in milk. Models included the main effects and all their possible two-way interactions; not estimable effects and non-significant (p>0.05) two-way interactions were dropped from the models. The three traits analyzed used Poisson distribution and a log link function and were determined with the Interactive Data Analysis of SAS software. Least square means and multiple mean comparisons were obtained and performed for significant main effects and their interactions (p<0.0255). RESULTS: Interaction of breed by gene showed that Holstein and Fleckvieh were the breeds on which CSN3 (6.01%±0.19% and 5.98%±0.22%), and LGB (6.02%±0.19% and 5.70%±0.22%) have the greatest influence. Interaction of breed by genotype nested in the analyzed gene indicated that Holstein and Jersey showed greater influence of the CSN3 AA genotype, 6.04%±0.22% and 5.59%±0.31% than the other genotypes, while LGB AA genotype had the largest influence on the traits analyzed, 6.05%±0.20% and 5.60%±0.19%, respectively. Furthermore, interaction of type of statistical model by genotype nested in the analyzed gene indicated that CSN3 and LGB genes had similar behavior, maintaining a difference of more than 7% across analyzed genotypes. These results could indicate that both Holstein and Jersey have had lower substitution allele effect in selection programs that include CSN3 and LGB genes than Brown Swiss and Fleckvieh. CONCLUSION: Breed determined which genotypes had the greatest association with analyzed traits. The mixed model based in Bayesian or Ridge Regression was the best alternative to analyze CSN3 and LGB gene effects on milk yield and protein and fat percentages.

Anthelmintic resistance in gastrointestinal nematodes from grazing beef cattle in Campeche State, Mexico.

Production of beef cattle is one of the most important economic activities in Mexico. However, anthelmintic resistance (AR) has affected animal productivity. The aim of this study was to determine the presence of AR in gastrointestinal nematodes (GIN) of beef cattle in Candelaria Municipality of Campeche State, Mexico. Sixty-five-month-old beef calves were selected for the faecal egg count reduction test (FECRT) and the inhibition of egg hatch (IEH) assay. These parameters were determined using albendazole (benzimidazole, BZ), ivermectin (IVM, Macrocyclic lactone, ML) and levamisole (LEV, imidazothiazole, IMZ). Allele-specific PCR (AS-PCR) confirmed polymorphisms at codon 200 of isotype 1 of the ß-tubulin gene of Haemonchus placei. The results showed 32 % IVM toxicity by FECRT, indicating problems of AR in the GIN population. In contrast, BZ and LEV showed 95 and 100 % toxicity, respectively, against GIN from infected beef calves. The infective larvae (L3) of Cooperia, Haemonchus and Oesophagostomum were identified before anthelmintic treatment, and Cooperia L3 larvae were identified after treatment with IVM. The IEH assays had lethal dose 50 (LD50) of 187 nM to BZ, confirming the ovicidal effect of BZ. In contrast, the LD50 for LEV and IVM were 3.3 and 0.4 mM, respectively. The results obtained by AS-PCR confirmed two DNA fragments of 250 and 550 bp, corresponding to the resistant and susceptible alleles in the H. placei population. The nematode Cooperia showed AR against IVM, while the toxicity effect of BZ against GIN with both FECRT and IEH was confirmed.

Polymorphism of three milk protein genes in Mexican Jersey cattle

The objective was to estimate the allelic and genotypic frequencies, genetic diversity and polymorphic information content for the β-casein, κ-casein and β-lactoglobulin genes. Blood and frozen semen samples were collected from 453 Jersey individuals registered by the Mexican Jersey Cattle Association. Twenty eight breed specific SNP primers for whole genes were used. The B allele of κ-casein had higher frequency (0.69) than the A (0.26) and E (0.05). For β-lactoglobulin, the highest frequency was for B (0.72), followed by A and C alleles (0.26 and 0.02, respectively). The β-casein allele with the highest frequency was A² (0.71), followed by A¹ (0.19), A³ (0.05), B (0.04) and C (0.01). The average genetic diversity (He) was 0.53. The average locus effective allele number was 1.79. These results indicate a high allelic diversity for κ-caseín, β-casein and β-lactoglobulin that could be included in breeding programs in the population studied, aimed to improve the milk quality traits of economic importance.

Survey of Mexican retail stores for US beef product.

Retail packages (N=1004) containing fresh US beef in display cases in five cities across three regions of Mexico were surveyed for cut types, cutting styles, fat thickness measurements, marbling scores, and USDA Quality Grades to gain an overview of fresh US beef in Mexican retail markets. Data were analyzed to generate frequency distributions and examine the effect of city, geographical region, store chain, and socio-economic status of the targeted clientele on type, cutting style, fat measures and quality of beef cuts of US origin. Top round, bottom round and knuckle were the most common cut types. Milanesa-type slice and "bistec" (steak for grilling) were the predominant cutting styles. Over 95% of the retail cuts were trimmed to 3.2mm or less of external fat. Most cuts were USDA Select (74.5%) and USDA Choice (24.5%). External fat thickness and marbling score differed among cities and store chains (P<0.01).

A modular neural network scheme applied to fault diagnosis in electric power systems.

This work proposes a new method for fault diagnosis in electric power systems based on neural modules. With this method the diagnosis is performed by assigning a neural module for each type of component comprising the electric power system, whether it is a transmission line, bus or transformer. The neural modules for buses and transformers comprise two diagnostic levels which take into consideration the logic states of switches and relays, both internal and back-up, with the exception of the neural module for transmission lines which also has a third diagnostic level which takes into account the oscillograms of fault voltages and currents as well as the frequency spectrums of these oscillograms, in order to verify if the transmission line had in fact been subjected to a fault. One important advantage of the diagnostic system proposed is that its implementation does not require the use of a network configurator for the system; it does not depend on the size of the power network nor does it require retraining of the neural modules if the power network increases in size, making its application possible to only one component, a specific area, or the whole context of the power system.

Genotype by climate interaction in the genetic evaluation for growing traits of Braunvieh cattle in Mexico.

The objective of this study was to determine the magnitude of genotype by climate interaction (GCI) in the national genetic evaluation for weaning (WW) and yearling (YW) weights of Mexican Braunvieh cattle. The numbers of performance records and animals in the pedigree were 12,364 and 25,173 for WW, and 7,991 and 18,072 for YW, respectively. Performance records were clustered based on climatological variables into: dry tropic (DT), wet tropic (WT), and temperate (TE) climates. Animal models were used to estimate genetic parameters and predict breeding values in each of the climates. Bivariate analyses were carried out for pairwise combinations of climates on each trait, considering the same trait in different climates as a different trait. Criteria to evaluate GCI were genetic correlations (r g), correlations between predicted breeding values (r BV), and frequencies of coincidence (FC) in the ranking of the top 25 sires. Results of comparisons between pairs of climates were variable, depending on specific cases. For WW, the r g, r BV, and FC ranged from -0.36 to 0.84, -0.60 to 0.97, and 0.16 to 0.92, respectively; whereas for YW, they fluctuated between 0.23 and 0.99, 0.33 and 1.00, and 0.60 and 1.00, respectively. For both traits, the results suggest absence of GCI between DT and TE; however, GCI was detected in the other pairs of climates, where WT was involved. To maximize genetic progress, the joint genetic evaluation should be performed only for animals with performance data in DT and TE, whereas a separated evaluation is suggested for animals with performance records generated under WT conditions.

Comparación de ecuaciones para ajustar curvas de lactancia en bovinos / Comparison of equations to fit lactation curves of cattle

El objetivo fue evaluar la bondad de ajuste de 16 ecuaciones para ajustar curvas de lactancia en seis genotipos bovinos. Se analizaron registros semanales o mensuales de producción de leche de vacas Pardo Suizo Americano (n=826 lactancias), Bos indicus (BI, n=52), ¾BI»Bos taurus (BT, n=507), ½BI½BT (n=462), 3/8 BI 5/8 BT (n=167) y »BI¾BT (n=62). Los parámetros de las ecuaciones se estimaron, para cada lactancia individual, por regresión lineal y no lineal, y las comparaciones se realizaron con base en los cuadrados medios de residuales, mediante la jerarquización dentro de genotipo utilizando la prueba de Suma de Rangos de Friedman. Otros criterios adicionales fueron la proporción de casos con producción de leche diaria anormal y los casos con autocorrelación positiva. Existieron diferencias (P<0,05) en la bondad de ajuste de las ecuaciones a través de genotipos. Sin embargo, para todos los genotipos la ecuación de mejor ajuste (P<0,05) fue una reparametrización de la ecuación de Wood, la cual considera la primera fecha de muestreo como el tiempo cero.

The objective was to evaluate the goodness of fit of 16 equations to estimate lactation curves of six cattle genotypes. Monthly or weekly milk production records of Brown Swiss (n=826 lactations), Bos indicus (BI, n=52), ¾BI»Bos taurus (BT, n=507), ½BI½BT (n=462), BIBT (n=167) and »BI¾BT (n=62) cows were analyzed. Fitting of equations to individual lactations was performed by linear or non-linear regression. The residual mean squares obtained after fitting of the equations were ranked within genotype and compared by Friedman’s test. Additional criteria to compare the equations were the proportion of cases of abnormal daily milk production, and cases with positive autocorrelation. Equations differed (P<0.05) on their suitability to properly describe lactation curves across genotypes. However, for all genotypes the equation of best fit (P<0.05) was a reparameterization of Wood’s equation in which the first test date is considered as time zero. The use of this equation is recommended to fit lactation curves of cattle genotypes such as the ones evaluated in this study.