Growth Trait Heredity in Two Cavy Sublines Native to the Ecuadoran Mountain Range

Background: No studies have been published on South American cavy preservation and breeding programs; therefore, the aim of this article was to analyze the genotypic and environmental factors that act upon the growth traits of a South American native cavy line found in the Ecuadoran Mountain Range. Methods: The study took place on Irquis experimental farm, from the Faculty of Agricultural Sciences, University of Cuenca, using two native cavy sublines from rural breeders in provinces Azuay and Cañar. Weight per age and daily weight gain (g) were analyzed by a mixed variance analysis of litter size (5), season (semester), sex, and parturition number of the mother as fixed effects, using software R 3.4.4. The random effects were made by sub-lines Azuay (1) and Cañar (2), and their male parents. The basic statistical values were determined. Results: Birth weight, weaning weight, and weight at 90 days in grams, were 110.2 ± 1.81, 117.0 ± 1.44; 212.2 ± 4.30 and 221.13 ± 3.38; 540.7 ± 12.01, and 659.1 ± 9.44, respectively. The heredity values for these traits were 0.09 ± 0.101, 0.34 ± 0.201, and 0.11 ± 0.111. Besides, weight was analyzed at 30, 45, 60, 75, and 90 days after birth, which included gains at every age. The BLUP predictors for the parents of the two sub-lines were determined. Variation and heritability allowed for selection of weight at weaning and at 90 days. Conclusions: This line showed low growth levels, though the variations observed were adequate. Their heredity might lead to the expected favorable results, provided a selection program is implemented in the mid-term.Background: No studies have been published on South American cavy preservation and breeding programs; therefore, the aim of this article was to analyze the genotypic and environmental factors that act upon the growth traits of a South American native cavy line found in the Ecuadoran Mountain Range. Methods: The study took place on Irquis experimental farm, from the Faculty of Agricultural Sciences, University of Cuenca, using two native cavy sublines from rural breeders in provinces Azuay and Cañar. Weight per age and daily weight gain (g) were analyzed by a mixed variance analysis of litter size (5), season (semester), sex, and parturition number of the mother as fixed effects, using software R 3.4.4. The random effects were made by sub-lines Azuay (1) and Cañar (2), and their male parents. The basic statistical values were determined. Results: Birth weight, weaning weight, and weight at 90 days in grams, were 110.2 ± 1.81, 117.0 ± 1.44; 212.2 ± 4.30 and 221.13 ± 3.38; 540.7 ± 12.01, and 659.1 ± 9.44, respectively. The heredity values for these traits were 0.09 ± 0.101, 0.34 ± 0.201, and 0.11 ± 0.111. Besides, weight was analyzed at 30, 45, 60, 75, and 90 days after birth, which included gains at every age. The BLUP predictors for the parents of the two sub-lines were determined. Variation and heritability allowed for selection of weight at weaning and at 90 days. Conclusions: This line showed low growth levels, though the variations observed were adequate. Their heredity might lead to the expected favorable results, provided a selection program is implemented in the mid-term

Influence of Penile Spicules of Covies(Cavia porcellus)on their Sexual Behavior, Fertility and Sperm Quality

This research took place in canton Cuenca, province of Azuay, Ecuador, located on UTM 717386 x 9675751, 2 714 meters above sea level, with a mean temperature of 14°C. The study determined the influence of penile spicules on sexual behavior, fertility and sperm quality parameters in cavies (Cavia porcellus), raised on the Ecuadoran highlands. A number of 5 whole males (with penile spicules), and other 5 males with their spicules removedwere included in the study, along with 40 nulliparous females, type A, pelage type 1. The pregnancy percentage of females that copulated with extirpated males decreased 65% in relation to the control group (P<0.05). However, the sexual behavior pattern and sperm quality of the two groups in the study were similar (P>0.05). Therefore, the study concluded that extirpation of the penile spicules has effects on fertility, but not on sexual behavior and sperm quality

Heredabilidades de rasgos de crecimiento de dos sublíneas de cuyes nativos de la sierra ecuatoriana

Background: There are no studies that allow developing these programs for their conservation and genetic improvement of South American cobays. The objective of this article was analyze genotypic and environmental factors that influence the growth traits of a native line of guinea pigs from the south of the Ecuadorian highlands. Methods: The work was carried out in the experimental farm of Irquis of the Faculty of Agricultural Sciences of the University of Cuenca, with guinea pigs belonging to two native sublines originating from rural breeders of the provinces of Azuay and Cañar. The weight-for-age traits and the daily weight gains measured in grams were analyzed using a mixed variance analysis model with the fixed effects; size of litter (5), time (semester), sex and number of delivery of the mother with software R 3.4.4. The sub-lines Azuay (1) and Cañar (2) and the parents within sublines formed the random effects. The basic statisticians were determined. Results: The weights at birth, at weaning and at 90 days, measured in grams, were 110.2 ± 1.81, respectively, and 117.0 ± 1.44; 212.2 ± 4.30 and 221.13 ± 3.38; 540.7 ± 12.01 and 659.1 ± 9.44. The heritabilities for these characters were 0.09 ± 0.101; 0.34 ± 0.201 and 0.11 ± 0.111. In addition, weights were analyzed at 30; Four. Five; 60; 75 and 90 days of births and earnings among all ages. The BLUP predictors were determined for the parents of both su-blíneas. Variation and heritabilities allow to apply selection in the weight at weaning and at 90 days. Conclusions: The line showed low growth levels, but there is enough variation and its heritabilities would allow to expect favorable progress in case of a medium-term selection program.Antecedentes: No existen estudios que permitan desarrollar esos programas para su conservación y mejoramiento genético de cobayos suramericanos. El objetivo de este artículo fue analizar factores genotípicos y ambientales que influyen en los rasgos de crecimiento de una línea nativa de cuyes del sur de la sierra ecuatoriana. Métodos: El trabajo se llevó acabo en la granja experimental de Irquis de la Facultad de Ciencias Agropecuarias de la Universidad de Cuenca, con cobayos pertenecientes a dos sublíneas nativas originarias de criadores rurales de las provincias de Azuay y Cañar. Los rasgos de pesos por edad y las ganancias en peso diario medidos en gramos fueron analizados mediante un modelo de análisis de varianza mixto con los efectos fijos; tamaño de la camada (5), época (semestral), sexo y número de parto de la madre con el software R 3.4.4. Las sublíneas Azuay (1) y Cañar (2) y los padres dentro de sublíneas conformaron los efectos aleatorios. Se determinaron los estadígrafos básicos. Resultados: Los pesos al nacer, al destete y a los 90 días, medidos en gramos, fueron 110,2 ± 1,81, respectivamente, y 117,0 ± 1,44; 212,2 ± 4,30 y 221,13 ± 3,38; 540,7 ± 12,01 y 659,1 ± 9,44. Las heredabilidades para estos caracteres fueron 0,09 ± 0,101; 0,34 ± 0,201 y 0,11 ± 0,111. Además, se analizaron los pesos a los 30; 45; 60; 75 y 90 días de nacidos y las ganancias entre todas las edades. Se determinaron los predictores BLUP para los padres de ambas sublíneas. La variación y las heredabilidades permiten aplicar selección en el peso al destete y a los 90 días. Conclusiones: La línea mostró niveles de crecimiento bajos, pero hay suficiente variación y sus heredabilidades permitirían esperar progresos favorables en caso de realizarse un programa de selección a mediano plazo

Removal of Penile Spicules of Covies (Cavia porcellus) and its Effect on Weight Gain and Aggressiveness

This research took place on Irquis Farm, University of Cuenca, Victoria del Portete parish, Cuenca canton, prov-ince of Anzuay, Ecuador. The effects of penile spicule extirpation on weight gain and aggressiveness, and damage caused to the carcass at the beginning of growing/fattening were studied. The study consisted of three treatments: whole animals without castration, used as controls (T1); animals with extirpation of the glans´s spicules (T2); and chemically castrated animals, using 0.5 ml of 2% alcohol with iodine, directly injected in each testicle (T3). A total of 90 animals were included, following a randomized block design with six treatments and five replicas. The diet consisted of forage mixture of 33-35% dry matter, and a commercial feed supplement administered ad libitum. A co-variance analysis (ANACOVA) was made using the initial weight as co-variable. The final weight was significantly influenced by the treatment; the Tukey´s test resulted in higher final weight in T2, followed by T1. Their behavior was significantly different from T3 (P < 0.05). In relation to aggressiveness expressed in carcass damage, no signifi-cant differences were observed, according to Chi-square test (P > 0.05)

Fodder, Nitrogen, and Energy Balances in Grasslands with Algarroba Trees (Prosopis juliflora (S.W.) DC.) under Dairy Cow Grazing

The purpose of this study was to evaluate the effect of algarroba (Prosopis juliflora (S.W.) DC.) on fodder, nitrogen and energy contents in Ecuadoran dairy farm grasslands. The study was made at ESPAM bovine facility, 15 meters above sea level, in Manabí, 00º49’23’’, south latitude, and 80º11’01” west longitude, with 962.4 mm of annual precipitation, between September 2011 and December 2014. The stocking rate was 1.09 LU/ha. The areas were populated with 1-4 algarroba trees/ha by 2011, and 8-35 trees/ha, in 2014. Fodder, nitrogen, and energy balances depended on the arborization degree. As a result, 52 t of DM were estimated in 2014, in comparison to the 21 t produced in 2011. Nitrogen was higher with increased arborization between 2011 (60.9 kg/ha), greater nutrient intake from external sources, and 2014 (39.3 kg/ha), with less use of supplements and mineral fertilizers, and greater N2 contribution by arborization. The energy values were higher in 2014, with an increase in algarroba population/ha. The rise in trees/ha in 2014 favored forage yields, with improved N2 and energy efficiency, which was linked to the benefits acquired by the grassland, the contribution of nitrogen to the ecosystem, and the reduction in feed and fertilizer consumption, which led to energy savings