Demi-embryo reconstitution, a factor to consider for the success of embryo bisection. Review

Durante muchos años se ha intentado incrementar la eficiencia reproductiva del ganado utilizando biotecnologías como la bisección de embriones. Sin embargo, pese a su potencial en el ganado, su nivel de adopción es limitado. Este trabajo reseña la importancia de la reconstitución de los demi-embriones después de la bisección y los principales factores que limitan su éxito en el ganado. El uso de esta técnica podría ser más generalizado si se incrementara su eficiencia, lo cual podría lograrse mediante una selección más precisa de los embriones que se someterán a bisección. La calidad de los embriones es uno de los factores más importantes que determinan su potencial de reconstituirse en demi-embriones viables después de la bisección, permitiendo obtener resultados más confiables en los programas de transferencia de embriones.For many years it has been sought to increase the reproductive efficiency of livestock using biotechnologies such as embryo bisection. However, despite its potential in livestock, its level of adoption is limited. The present work reviews the importance of demi-embryo reconstitution, after bisection, and the main factors that limit its success in livestock. It is possible to increase its level of adoption if it is possible to increase the efficiency currently obtained with this technique, this can be achieved by making a more precise selection of the embryos subjected to bisection. Embryo quality is one of the most important factors related to the potential to reconstitute into viable demi-embryos after bisection, which can be used with greater reliability in embryo transfer programs

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

Efecto de la fuente de selenio en el comportamiento productivo, contenido de selenio en suero y músculo, y nivel sérico de albúmina, α-, β- y ∂-globulinas en ovinos Pelibuey

The objective was to compare the effects of sodium selenite (SS) and Sel-Plex® (SP) on dry matter intake (DMI), daily weight gain (DWG), feed conversion (FC), carcass yield, Se in serum, muscle, albumin, and globulins in Pelibuey lambs. Fifty (50) animals (LW=23.0 ± 1.1 kg; 5 to 6 mo) were stratified and randomly assigned to one of five treatments (n=10): 1) Basal diet, C); 2) C + 0.30 mg kg-1 DM of SS, 30SS; 3) C + 0.90 mg kg-1 DM of SS, 90SS; 4) C + 0.30 mg kg-1 DM of SP, 30SP; and 5) C + 0.90 mg kg-1 DM of SP, 90SP. There was no effect (P>0.05) on DMI; while 90SP and 30SS showed higher DWGs (293 and 260 vs 245, 243, and 230 g d-1; P0.05). In the Longissimus dorsi, 30SP increased (P0.05) on the Gluteus maximus and Musculus deltoideus. Albumin was higher with 30SP and 90SS; while α-globulin was higher with 30SS and 90SP. In conclusion, 0.90 mg of SP improved DWG and FC. Selenite and SP increased Se in serum up to 0.30, and it decreased with 0.90 mg per kilogram of SP. In the Longissimus dorsi, Se was improved in 30SP with respect to 90SP and C and was not similar to 90SS and 30SS. The organic Se of 90SP improved the level of albumin and α-globulins.El objetivo fue comparar los efectos de selenito de sodio (SS) y Sel-Plex® (SP) en el consumo de materia seca (CMS), ganancia diaria de peso (GDP), conversión alimenticia (CA), rendimiento de canales, Se en suero, músculos, albúmina, y globulinas en corderos Pelibuey. Cincuenta animales (PV=23.0 ± 1.1 kg; de 5 a 6 meses) se estratificaron y aleatoriamente asignaron a uno de cinco tratamientos (n=10): 1) Dieta basal, C); 2) C + 0.30 mg kg-1 MS de SS, 30SS; 3) C + 0.90 mg kg-1 MS de SS, 90SS; 4) C + 0.30 mg kg-1 MS de SP, 30SP; y 5) C + 0.90 mg kg-1 MS de SP, 90SP. No hubo efectos (P>0.05) en CMS; mientras que 90SP y 30SS mostraron GDP mayores (293 y 260 vs 245, 243, y 230 g día-1; P0.05). En Longissimus dorsi, 30SP incrementó (P0.05) en Gluteus maximus y Musculus deltoideus. La albúmina fue mayor con 30SP y 90SS; mientras que α-globulina fue mayor con 30SS y 90SP. En conclusión, 0.90 mg de SP mejoró la GDP y CA. Selenito y SP aumentaron el Se en suero hasta 0.30, y disminuyó con 0.90 mg por kilo de SP. En  Longissimus dorsi, el Se se mejoró en 30SP con respecto 90SP y el C y no fue similar a 90SS y 30SS. El Se orgánico de 90SP mejoró el nivel de albúmina y α-globulinas

Caracterización técnica, social y económica de las empresas del hato bovino jersey de registro en México

In México, there are no studies whose purpose has beencharacterizing the production units with registered cattle herds.These studies are important because they allow designingsuccessful genetic improvement programs and the transfer oftheir results to commercial producers. The objective of thisstudy was to characterize registered Jersey herds in México.A questionnaire was applied to all of the members of theAsociación Mexicana de Criadores de Ganado Jersey de Registro,and descriptive statistics were obtained. The registered Jerseycattle population in México is small (approximately 4000animals), it is distributed primarily in the central area of thecountry, and most of the herds (85%) have a recent origin(since 1995). Selection in the herds is scarce, activities forgenetic improvement are focused on identifying the animalsand collecting productive records; therefore, genetic progressis primarily through semen and animal imports, generatingtechnical and economic dependency on other countries. In spiteof having national genetic evaluations of the animals, theircommercialization by farmers is not the main activity, which iswhy the transfer of outstanding genetic material to commercialproducers is scarce. The installed capacity in animals, lands,and infrastructure and equipment is sufficient to implementgenetic improvement programs. Jersey cattle producers have inaverage 15 years of schooling and 24 in cattle-raising.En México no se dispone de estudios cuyo propósito haya sido lacaracterización de las unidades de producción con hatos de bovinosde registro. Estos estudios son importantes, ya que permitendiseñar programas de mejoramiento genético exitosos y la transferenciade sus resultados a productores comerciales. El objetivode este estudio fue caracterizar los hatos Jersey de registro enMéxico. Se aplicó un cuestionario a la totalidad de los miembrosde la Asociación Mexicana de Criadores de Ganado Jersey deRegistro y se obtuvieron estadísticos descriptivos. La poblaciónde bovinos Jersey de registro en México es pequeña (aproximadamente4000 animales), se distribuye principalmente en elcentro del país y la mayoría de los hatos (85%) tienen un origenreciente (a partir de 1995). La selección en los hatos es escasa,las actividades de mejoramiento genético se enfocan a identificarlos animales y recolectar registros productivos; por lo que elprogreso genético es principalmente vía importaciones de semeny animales, generando dependencia técnica y económica de otrospaíses. A pesar de contar con evaluaciones genéticas nacionalesde los animales, su comercialización por criadores no es la actividadprincipal, por lo que la transferencia de material genéticosobresaliente a productores comerciales es escasa. La capacidadinstalada en animales, terrenos, e infraestructura y equipo es suficientepara implementar programas de mejoramiento genético.Los criadores de bovinos Jersey tienen en promedio 15 años deescolaridad y 24 de experiencia en la cría de bovinos

Comparación de definiciones de grupos contemporáneos en la evaluación genética de bovinos Suizo Europeo

Six alternatives of contemporary group (CG) definition for the genetic evaluation of weaning weight of Braunvieh cattle in Mexico were evaluated. Different alternatives of CG definition were formed by combining three minimum CG sizes (3, 7 or 10 records) and its consideration either as a fixed or random effect. The models included the direct and maternal genetic effects, their covariance, and permanent environment as random effects, and the linear and quadratic effects of cow age at calving as a covariate. The CG were formed by combining the effects of year and season of birth, calf's rearing condition, herd, and calf sex. The six alternatives of CG definition were compared using the descriptive statistics of the predicted breeding values and their accuracies, (co)variances and genetic parameters, and both the correlation between the predicted breeding values, and between their corresponding accuracies. On average, the accuracies of the direct genetic effects were slightly higher when CG was considered fixed than when it was fitted as random effect. For the maternal genetic effects there was no difference. The highest accuracies were obtained with a CG size of at least seven records. For both, the direct and maternal genetic effects, the CG size of seven records produced the highest heritability estimates, regardless of CG being fitted as fixed or random effect. The best alternative of contemporany group definition was a minimum of seven records and its inclusion as a fixed effect in the model for the genetic evaluation of this breed in Mexico.Se evaluaron seis alternativas para definir grupos contemporáneos (GC) en la evaluación genética nacional para peso al destete de bovinos Suizo Europeo en México. Los GC se formaron mediante la combinación de tres tamaños mínimos (3, 7 ó 10 registros) y su consideración como efecto fijo o aleatorio. Los modelos incluyeron los efectos aleatorios: genético directo y materno, su covarianza, y ambiente permanente. Además, se consideraron los efectos lineal y cuadrático de la covariable edad de la vaca al parto. Los GC se formaron combinando los efectos de año y época de nacimiento, condición de crianza, hato y sexo de la cría. Las seis alternativas de GC se compararon mediante: estadísticos descriptivos de los valores genéticos predichos y sus exactitudes, (co)varianzas y parámetros genéticos, y asociaciones entre los valores genéticos predichos, y entre las exactitudes correspondientes. Para los efectos genéticos directos, los promedios de exactitud fueron ligeramente mayores considerando GC como aleatorio en lugar de fijo, mientras que para los efectos genéticos maternos no hubo diferencias. Las exactitudes mayores se obtuvieron con un mínimo de siete registros por GC. Tanto para efectos genéticos directos como maternos, los estimadores de heredabilidad más altos se observaron con el tamaño mínimo de siete registros por GC, independientemente si los análisis lo consideraron como efecto fijo o aleatorio. La mejor alternativa de definición de grupos contemporáneos fue considerar un mínimo de siete registros y su inclusión como efecto fijo en los análisis genéticos para esta raza en México

Desempenho produtivo de porcos Pelón Mexicano em iniciação alimentados com três níveis de lisina na dieta

The productive behavior of the Mexican Hairless pig fed with 100, 80 and 60 %Lys (T1, T2 and T3) of the dietary level of lysine recommended by the NRC for commercial pigs was studied. 12 piglets randomly distributed in three treatments were used, with an average initial weight of 12.00 ± 1.28 kg. Each treatment had four repetitions, the experimental unit was a piglet. The animals were weighed every week from the beginning to the end of the experiment; when they reached 25 kg of live weight they were sacrificed. The variables evaluated were: live weight (LWn), feed intake (CDAn), daily weight gain (GDPn) and feed conversion (CAn), n=week from 1 to 7. The results were processed by ANOVA and Tukey when (p<0.05). By reducing the level of lysine included in the diet, most of the variables analyzed were not affected. The growth curves presented by the animals were similar, so they followed the same growth rate. The treatment effect was significant (P<0.0198) for CDA1 and PV3. This suggests that nutritional lysine requirements for growing Mexican Hairless pigs could be up to 60% of those specified by the NRC for improved pigs, without compromising their productive capacity at 25 kg.Se estudió el comportamiento productivo del cerdo Pelón Mexicano alimentado con 100, 80 y 60% (T1, T2 y T3) del nivel dietético de lisina recomendado por el NRC para cerdos comerciales. Se usaron 12 lechones distribuidos aleatoriamente en tres tratamientos, con 12.00±1.28 kg de peso inicial promedio. Cada tratamiento tuvo cuatro repeticiones, la unidad experimental fue un lechón. Los animales se pesaron cada semana del inicio al final del experimento; cuando alcanzaron 25 kg de peso vivo se sacrificaron. Las variables evaluadas fueron: peso vivo (PVn), consumo de alimento (CDAn), ganancia diaria de peso (GDPn) y conversión alimenticia (CAn), n=semana de la 1 a la 7. El análisis se realizó con el procedimiento GLM de SAS, cuando el efecto de tratamiento fue significativo (p<0.05), las medias correspondientes se compararon con la prueba Tukey. El efecto de tratamiento fue significativo (P<0.0198) para CDA1 y PV3. El nivel de lisina incluido en la dieta no afectó la mayoría de las variables analizadas. Esto sugiere que los requerimientos nutricionales de lisina para cerdos Pelón Mexicano en crecimiento podrían ser hasta 60% de los especificados por el NRC para cerdos mejorados, sin comprometer su capacidad productiva a 25 kg.Estudou-se o comportamento produtivo do porco mexicano sem pêlo alimentado com 100, 80 e 60% Lys (T1, T2 e T3) do nível dietético de lisina recomendado pelo NRC para suínos comerciais. Foram utilizados 12 leitões distribuídos aleatoriamente em três tratamentos, com peso médio inicial de 12,00 ± 1,28 kg. Cada tratamento teve quatro repetições, a unidade experimental foi um leitão. Os animais foram pesados ​​semanalmente do início ao fim do experimento; quando atingiram 25 kg de peso vivo foram sacrificados. As variáveis ​​avaliadas foram: peso vivo (LWn), consumo de ração (CDAn), ganho de peso diário (GDPn) e conversão alimentar (CAn), n=semana de 1 a 7. Os resultados foram processados ​​por ANOVA e Tukey quando (p <0,05). Ao reduzir o nível de lisina incluído na dieta, a maioria das variáveis ​​analisadas não foi afetada. As curvas de crescimento apresentadas pelos animais foram semelhantes, portanto seguiram a mesma taxa de crescimento. O efeito do tratamento foi significativo (P<0,0198) para CDA1 e PV3. Isso sugere que os requisitos nutricionais de lisina para suínos mexicanos calvos em crescimento podem ser de até 60% daqueles especificados pelo NRC para suínos melhorados, sem comprometer sua capacidade produtiva de 25 kg

Efeito do tamanho e sexo dos suínos no início da fase de terminação sobre os indicadores produtivos no final da engorda

The effect of segregation by sex and size at the start of the growing-finishing stage on traits at the end of the fattening and at slaughter was studied in commercial pigs, 121 Danbreed×Pietrain pigs were used, entire males and females. They were divided in good and bad males, and good and bad female groups (G). They were housed in 9 m2 pens. The pigs received clean, fresh water, and ad libitum food and water. The initial weight varied from 12.4±2.0 to 25.3±2.3 kg. The target weight was 115 kg. Fattening was divided into growth (0-60 d) and finishing phases (60-120 d). The response variables were initial (P1), intermediate (P2), and final weight (P3); total feed intake (CMD); daily weight gain between P1 and P2 (GDP1y2), P2 and P3 (GDP2y3), and P1 and P3 (GDP1y3); and feed conversion ratio (CA). The pigs that reached the target weight in 114 d were termed "first quality", the "second quality" in 122 d, the "underachievers" did not reach this weight in 122 d. The GLM procedure of SAS and statistical analysis with learning machines in R were used to analyze the of productive variables and to determine the factors affecting the quality of the pigs at the end of fattening. The females exceeded (P≤0.0263) the males by 2.72 kg and 0.05 kg d-1 for P2 and GDP1y2. The sex*G interaction affected (P≤0.0181) P3, GDP1y3, and GDP2y3. Sex of pig and G were not the most important factors to classify quality at the end of fattening. Regrouping pigs by sex and size at the beginning of the growth-finishing phase affected significantly the productive performance and indirectly influences quality at the end of fattening.El objetivo fue estudiar el efecto de la segregación por sexo y tamaño al iniciar el crecimiento-finalización en características al finalizar la etapa y al sacrificio en cerdos comerciales. Se utilizaron 121 cerdos Danbreed×Pietrain; hembras y machos enteros, clasificados por sexo y crecimiento en: machos buenos y malos y hembras buenas y malas. Los cerdos se alojaron en corrales de 9 m2. El agua y alimento fueron limpios, frescos y ad libitum. El peso inicial por grupo varió de 12.4±2.0 a 25.3±2.3 kg. El peso objetivo fue 115 kg. La engorda se dividió en crecimiento (0-60 d) y finalización (60-120 d). El peso vivo inicial (P1), intermedio (P2) y final (P3); consumo total de alimento (CMD); ganancia diaria de peso entre P1 y P2 (GDP1y2), P2 y P3 (GDP2y3), P1 y P3 (GDP1y3); y conversión alimenticia (CA) fueron las variables de respuesta. Los cerdos que llegaron al peso objetivo en 114 d se denominaron “primera calidad”, los de “segunda calidad” en 122 d, los “saldos” no lo alcanzaron en 122 d. El procedimiento GLM de SAS y análisis estadístico con máquinas de aprendizaje en R se utilizaron para determinar las variables productivas y los factores que influyen la calidad de los cerdos al finalizar la engorda. Las hembras superaron (P≤0.0263) a los machos por 2.72 kg y 0.05 kg día-1 para P2 y GDP1y2. La interacción macho*malo fue significativa (P≤0.0181) para P3, GDP1y3 y GDP2y3. El sexo y grupo de crecimiento no fueron factores importantes para determinar la calidad al finalizar la engorda. Reagrupar los cerdos por sexo y tamaño al iniciar la fase crecimiento-finalización afecta significativamente el comportamiento productivo e influye indirectamente la calidad al finalizar la engorda.O efeito da segregação por sexo e tamanho no início da fase de crescimento-terminação nas características no final da engorda e no abate foi estudado em suínos comerciais, foram utilizados 121 suínos Danbreed×Pietrain, todos machos e fêmeas. Eles foram divididos em grupos de machos bons e maus e grupos de fêmeas boas e más (G). Eles foram alojados em baias de 9 m2. Os suínos receberam água limpa e fresca e comida e água ad libitum. O peso inicial variou de 12,4±2,0 a 25,3±2,3 kg. O peso-alvo era de 115 kg. A engorda foi dividida em fases de crescimento (0-60 d) e terminação (60-120 d). As variáveis de resposta foram peso inicial (P1), intermediário (P2) e final (P3); consumo total de ração (CMD); ganho de peso diário entre P1 e P2 (GDP1y2), P2 e P3 (GDP2y3) e P1 e P3 (GDP1y3); e razão de conversão alimentar (CA). Os suínos que atingiram o peso alvo em 114 d foram denominados de "primeira qualidade", os de "segunda qualidade" em 122 d, os "underachievers" não atingiram esse peso em 122 d. O procedimento GLM de SAS e análise estatística com máquinas de aprendizagem em R foram utilizados para analisar as variáveis produtivas e determinar os fatores que afetam a qualidade dos suínos no final da engorda. As fêmeas excederam (P≤0,0263) os machos em 2,72 kg e 0,05 kg d-1 para P2 e GDP1y2. A interação sexo*G afetou (P≤0,0181) P3, GDP1y3 e GDP2y3. O sexo do porco e o G não foram os fatores mais importantes para classificar a qualidade no final da engorda. O reagrupamento dos suínos por sexo e tamanho no início da fase de terminação afeta significativamente o desempenho produtivo e influencia indiretamente a qualidade no final da engorda

Accuracy of genomic values predicted using deregressed predicted breeding values as response variables

Highly accurate predicted genetic values must be obtained at an early age to promote rapid genetic progress. The objectives of this study were to compare accuracies (R2) of genomic values (GVs) and to estimate genetic correlation between true genetic values and genomic values obtained using predicted breeding values (EBV) and deregressed EBV (DEBV) as response variables. A first population, effective population size 800 and 100 generations, was simulated using the QMSim program to generate linkage disequilibrium. Thereafter, 20 males and 200 females were used to generate a second 14-generation population, with 6,400 individuals per generation and its corresponding phenotype and genotype in SNP terms. Generations 7 to 14 of the second population were used in several combinations as training (PEn) and evaluation (PEv) subpopulations. GVs, their accuracies, and genetic correlations were obtained using the GenSel and ASREML programs. When PEn was the largest, the mean R2 of GV was the highest, 0.77 ± 0.01. The closer PEn was to PEv, the higher the R2, and correspondingly, the lower the predicted error variance. The trends for R2 and PEV held true for both EBV and DEBV used as response variables. Genetic correlation estimates between true genetic values and GVs varied from 0.41 to 0.53 in the two scenarios studied. They decreased when PEn and PEv were farther apart. There were only slight advantages of using DEBVs as response variables over using EBVs