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The National Institute of Forestry, Agricultural and Livestock Research (INIFAP) in Mexico has been studying the Criollo Coreño (C) cattle of the Sierra Madre Occidental for over 20 yr. This review covers productive, genetic and molecular characterization, as well as short-, medium- long-term research challenges and outlooks. Evaluations have been done of 35 growth, carcass quality, fertility and milk production traits in C, Guzerat (G), CG and GC cattle generated through diallelic crossing. Individual heterosis was found to affect reproduction and milk production, while maternal heterosis influenced kilograms of calf weaned per cow exposed. Direct and maternal genetic effects had no relevant influence on the analyzed variables. In other studies, C bulls fed high energy diets were found to produce meat with favorable fatty acid profiles and good quality carcasses, while low doses of FSH can be used for superovulation in C heifers, without affecting embryo production. Overall, the results indicate that GC cows are the best option for calf production, and that the C population maintains significant levels of genetic diversity. Further genetic diversity research is needed on Mexican Criollo cattle populations using molecular genetics; Criollo herds must be included in the systematic recording of phenotypes of productivity and adaptability to be able to identify genes of interest unique to Criollo cattle. [ABSTRACT FROM AUTHOR]

Four thousand twenty-five observations of three complete diallelic crossings between four rabbit breeds (California, C; Chinchilla, CH; New Zealand, N and Semi-giant, S) were conducted to determine the racial and heterosis effects on prolificacy traits. In the first study, a generalized linear model through the GENMOD procedure of SAS (2007), was applied which considered the race effects (paternal, maternal and their interaction), parity and generation. In the second, a mixed model through the PROC MIXED procedure, also of SAS, was used, which considered the genotype (cross vs. pure) as random and parity and generation as fixed. The BLUPs resulting from the second model were used when calculating heterosis. The indictors total born (TB), born alive (BA) and number of weaned animals (NW) were analyzed. The maternal breed was the only important effect for the TB and BA. Chinchilla breed highlighted with more than seven kids for both measurements. Non-significant positive heterosis was found in the reciprocal crossings CCH-CHC for each trait under study, as in the CN-NC for the NW. Heterosis was negative or null in the other combinations. The use of C as maternal breed is a way to improve the traits TB and BA. Advantages at the heterosis level are obtained with the CH-CHC crossing for all the prolificacy traits studied and with that of CS-SC for the WN. These results show that crossing is an alternative to increase productivity in different rabbit exploitations. [ABSTRACT FROM AUTHOR]

The aim of this study was to research the effect of the genetic background (Retinto , Torbiscal , and their reciprocal crosses) on the subcutaneous fatty acids and the sensory characteristics of dry-cured shoulders from Iberian pig, and also to investigate whether there is some interaction between genotype and diet composition when pigs are reared indoors, to obtain information to improve the selection strategies for purebred Iberian pig. The genetic background affected both the fatty acid composition (C17:0, C17:1 n-7, C18:3 n-3 and C20:0 were significantly different) and the sensory characteristics (marbling, lean fibrousness, and flavour intensity and persistence were significantly influenced), which indicates that they should be taken into account in the selection strategies for purebred Iberian pig. In a similar way, the genotype × diet composition interaction also should be taken into account when selecting a genetic line or cross to be fed indoors on a particular diet because of its repercussion on the sensory characteristics. [ABSTRACT FROM AUTHOR]