Background: Genetic variability of populations is essential for their genetic conservation and improvement, and genealogy analysis is a useful tool to estimate it. Objective: To determine genetic variability and inbreeding levels in Tropical Milking Criollo (LT). Methods: This study analyzed the genealogy of LT using the ENDOG software. Registration certificates of 3,427 LT animals born between 1945 and 2013, and from 608 born between 1950 and 2013 were used. Two populations were defined: the first one with all registered animals (PLT), and the second with nucleus animals (PCP). Results: Estimates for PLT and PCP were: founders 890, 114; ancestors 855, 102; effective founders 111, 43; effective ancestors 72, 26, and effective population size 68.1 and 64.6, respectively. Inbreeding coefficients were 4.32 and 3.48% for the highest genetic integrity index; and the average relatedness (AR) coefficients were 1.19 and 5.55 for PLT and PCP, respectively. Genealogy depth was shallow in both populations, with full equivalent generations of 2.00 and 3.53. Global generation intervals were about seven years. Conclusions: The LT population is not endangered and its genetic improvement program should continue.

The aim of this study was to describe the early growth of Pelibuey lambs raised under an intensive production system in Colima, Mexico, using non-linear models. Weight data were collected from 433 lambs every 30 days from birth to 180 days of age, and growth curves were estimated using non-linear and linear models. According to goodness of fit criteria, the Linear, Gompertz, Logistic and Von Bertalanffy models are suitable and show a reasonable fit for describing Pelibuey lamb's growth, the Brody and Richards curves did not meet the convergence criterion. The parameter A denotes asymptotic weight; weight was higher in multiple born males and quadruplet born females in the Von Bertalanffy and Gompertz models, while it was also higher in males in the Logistic model. The parameter k represents maturation rate and indicates the growth speed in reaching asymptotic weight, being higher in single and twin females, and single males in all the non-linear models. From birth up to 90 days of age (weaning), weight of single lambs becomes greater than that of multiple born lambs, but from 90 days of age, weight of multiple born lambs tends to equal that of singles, which happens at 180 days of age. The early growth of Pelibuey lambs can be described with similar precision using linear and non-linear models.

Este libro es un ejercicio de memoria, un esfuerzo por visibilizar las historias de vida de jóvenes cuyo paradero, en la mayor parte de los casos, aún se ignora. Jóvenes que han sido criminalizados, estigmatizados o, como el menor de los agravios, ignorados, tanto por las autoridades que debieron encontrarlos como por una sociedad que teme involucrarse, que prefiere mirar hacia otro lado. La desaparición forzada de personas y la desaparición por particulares son crímenes que afectan no solo a la víctima directa. Estas historias muestran las muchas maneras en que la desaparición de un familiar destruye las vidas de los parientes cercanos y daña profundamente el tejido social. El libro es también un reconocimiento a los familiares –en su mayoría madres– que no han claudicado en la búsqueda, ya no de justicia, porque ellas saben que eso es inalcanzable en el país de la impunidad, sino de un vestigio, un fragmento, un indicio de sus seres queridos. Sus indagaciones para encontrar “en vida, en muerte o en fosas clandestinas” no se han detenido a lo largo de los años, ni siquiera en medio de la pandemia de covid-19, con todo lo que ello ha implicado. Con gran valentía y entrega reclaman su derecho a saber qué pasó, a conocer el paradero de sus familiares y, al menos, en la peor de las circunstancias, el derecho a una tumba digna para sus hijos.