Escherichia coli is a widespread environmental pathogen frequently causing dairy cow mastitis. This bacterium is particularly capable of acquiring antimicrobial resistance, which can have severe impacts on animal food safety and human health. The objective of the study was to investigate antimicrobial resistance and genetic correlations of E. coli from dairy cow mastitis cases in northern China.

Objective: The objective of this study was to estimate the heritability (h2 ), repeatability (r), and correlations (r yi yi ) in some traits of zootechnical interest in a population of New Zealand white rabbits of a tropical dry forest area. Materials and Methods: Three mating groups were formed, each one of 1 male and 70 females. The traits evaluated were littersize at birth (LB), born alive (BA), born dead (BD), litter weight born alive (LW), litter weight at weaning (LWW), weaning weight (WW), slaughter weight (SW), and carcass weight (CW). Weaning took place at 42 days, and the fattening phase lasted 60 ± 3 days. A descriptive statistical study was carried out on the study variables. Paternal heritability was esti mated (h2 f ) and maternal (h2 m), repeatability, rabbit index IC, and Pearsons correlations (r yi yi ) between traits. The descriptive statistics showed high variation for the BD traits. Results: The values of the productivity found were similar to those presented in studies around the world. h2 presented magnitudes between low and medium. h2 f ranged between 0.09 and 0.42 and between 0.11 and 0.45 for h2 m. In general, the values of h2 m were higher than the values of h2 f . The r valuesforthe traits LB, BA, LW, LWW, and SW presented low magnitude, while it was medium for WW and CW. From the values of r, IC was calculated for each of the rabbits, allowing their categorization, which will be used in future selection plans. r yi yi among the variables ranged from −0.01 to 0.860. They were generally positive and mostly not significant (p > 0.05); they took a magnitude from low to moderate, except for the correlation between LB and BA. Conclusion: The production of rabbits under tropical conditions is similar to other reports. The genetic parameters evaluated were medium-to-low, indicating a robust non-additive gene and/ or environmental effect. [J Adv Vet Anim Res 2021; 8(3.000): 471-478]