This study investigated the factors affecting piglet mortality (square root of mortality, SQRM) and average weaning weight (AWW) in commercial farms in central China. Information on sow diets, management and climate from 2478 weaning batches completed in 16 pig farms was collected from 2009 to 2013. Multi-level mixed models, which included batch level (level 1) and farm level (level 2), were used to analyze the factors associated with SQRM and AWW. The mean values of SQRM and AWW were 2.52% (SD = 0.96) and 7.31 (SD = 0.77), respectively. Lactation sow diets supplemented with oregano essential oils (OEOs) decreased the SQRM (P < 0.05) and increased the AWW of piglets (P < 0.01). The SQRM was lower in period 2 (June to September, hot) than in period 1 (February to May, warm) and period 3 (October to January, cold; P < 0.05 and 0.001, respectively). The AWW was lower in periods 2 and 3 than in period 1 (P < 0.01). In conclusion, supplying OEOs to lactation diets can increase the weaning weight and reduce the mortality of piglets. The sources of variations in SQRM and AWW are of greater concern in the warm season than in the hot season.

The ball-flower Ni(OH) 2 /NiOOH composites were successfully synthesized via a facile hydrothermal method, using nickel sulfate as precursor and urea as precipitant, and the rosin-based betaine zwitterionic surfactant as annexing agent. The optimum condition of preparing ball-flower Ni(OH) 2 /NiOOH composites was 10 g/L rosinbased betaine zwitterionic surfactant, at 180°C for 8 h. The ball-flower Ni(OH) 2 /NiOOH composites were consisted of nanosheets. X-ray diffraction, Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, and surface tension were used to characterize the as-prepared samples. The effect of rosinbased betaine zwitterionic surfactant on the morphology and size of ball-flower Ni(OH) 2 /NiOOH composites were investigated in details. Moreover, a possible formation mechanism was proposed based on the effect of the rosinbased betaine surfactant. The result revealed that the crystallinity of the ball-flower Ni(OH) 2 /NiOOH composites were improved by the rosin-based betaine surfactant, and the morphology and size of Ni(OH) 2 /NiOOH composites could be well controlled in the presence of the rosin-based betaine zwitterionic surfactant.

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This study aimed to establish a feasible model for analysing factors affecting piglet litter performance at birth. Data of 61,984 litters were collected from 16 herds, and general linear model (GLM), multilevel Poisson regression model (MPM) and multilevel linear model (MLM) were established to compare their goodness of fit for these data. Influencing factors of piglet litter performance at birth were analysed using the established optimal model. Results showed the intraclass correlation coefficients of total born piglets (TBP), piglets born alive (PBA), low‐birth‐weight piglets (LBW), and average birth weight of piglets (ABW) reached 27.89%, 23.88%, 24.66% and 22.27%, respectively (p < .05). Akaike's information criterion and Bayesian information criterion in MLM of TBP, PBA, LBW and ABW were lower than those in GLM. Pearson residuals in MPM increased to nearly 1 after introduction of a discrete scale factor, and the p values in MPM were similar to those in MLM. Analyses of MLM indicated crossbred sows with good management supplemented with oregano essential oil and farrowing at warm season had higher TBA, PBA and ABW, but lower LBW than other sows (p < .05). In conclusion, MLM is superior to GLM and can replace MPM in analysing discrete data with hierarchical structure in pig production. More importantly, other potential influencing factors of litter performance at birth can be analysed using the established MLM in the future.