Sir Ronald A. Fisher and the International Biometric Society.

The year 2012 marks the 50th anniversary of the death of Sir Ronald A. Fisher, one of the two Fathers of Statistics and a Founder of the International Biometric Society (the "Society"). To celebrate the extraordinary genius of Fisher and the far-sighted vision of Fisher and Chester Bliss in organizing and promoting the formation of the Society, this article looks at the origins and growth of the Society, some of the key players and events, and especially the roles played by Fisher himself as the First President. A fresh look at Fisher, the man rather than the scientific genius is also presented.

Retrospective Broiler Health Survey: Scope, Parameters, and Overall Trends.

A retrospective analysis encompassing 18 yr (1999-2016) of broiler chicken health surveys from broiler production complexes throughout the United States was conducted to identify trends and areas of opportunity. The analysis used necropsy data from 19,577 broiler chickens considered to be "healthy" or "clinically normal" by visual assessment. The very low incidence of dehydrated (0.01%) or undersized (0.02%) broilers is evidence that the objective of examining "healthy" birds was achieved. The results of the correlation analysis were what was expected for "healthy" broilers, with these birds having positive correlations with skin color and size of the bursa of Fabricius. The average age of broilers included in this analysis ranged from 26.2 days in 2008 to 33.7 days in 2013. The percentage of "normal" broilers (those without visible lesions or abnormalities) varied from 5.63% in 2012 to 28.33% in 1999. The results of this study identified four areas of opportunity for improving poultry health: 1) coccidiosis, 2) oral lesions and gizzard erosions, 3) retained yolks, and 4) pododermatitis.

Encuesta retrospectiva sobre la salud de los pollos de engorde: alcance, parámetros y tendencias generales. Se realizó un análisis retrospectivo que abarcó 18 años (1999-2016) de encuestas de salud de pollo de engorde de complejos de producción en los Estados Unidos para identificar tendencias y áreas de oportunidad. El análisis utilizó datos de necropsia de 19,577 pollos de engorde considerados "saludables" o "clínicamente normales" mediante evaluación visual. La incidencia muy baja de pollos de engorde deshidratados (0.01%) o de tamaño pequeño (0.02%) es evidencia de que se logró el objetivo de examinar aves "sanas". Los resultados del análisis de correlación fueron los esperados para pollos de engorde "sanos", ya que estas aves tuvieron correlaciones positivas con el color de la piel y el tamaño de la bolsa de Fabricio. La edad promedio de los pollos de engorde incluidos en este análisis osciló entre 26.2 días en 2008 y 33.7 días en 2013. El porcentaje de pollos de engorde "normales" (aquellos sin lesiones o anomalías visibles) varió del 5.63% en 2012 al 28.33% en 1999. Los resultados de este estudio identificaron cuatro áreas de oportunidad para mejorar la salud de las aves: 1) coccidiosis, 2) lesiones orales y erosiones de la molleja, 3) retención de saco vitelino y 4) pododermatitis.

Influence of growth rate on occurrences of pale muscle in broilers.

BACKGROUND: Pale broiler breast meat is a defect in commercial production operations. The incidence of pale broiler breast meat was examined in two commercial processing plants which had average growth rates of 59 g day(-1) and 46 g day(-1) and final average weights of 3.36 kg and 1.93 kg. Color measurements of dorsal and ventral surfaces and pH were completed to evaluate the impact of selection for growth on meat water-holding capacity. RESULTS: L* greater than 60 were observed in 57% of broilers selected for greater yield and 26% of slower growing broilers. Average L* between 10 growers was significantly different (P = 0.001). Pearson's correlation coefficients for pH and L* were - 0.51 and - 0.27 for the faster growing broilers and slower growing broilers, respectively. The Pearson correlation coefficients between water-holding capacity and L* and pH was - 0.35 and 0.42, respectively. There was a higher correlation between production factors (age, weight and grower) and a* and b* than L* for ventral surface measurements. CONCLUSION: Breasts from broilers selected for faster growth tend to have lighter color. Weak correlation with water-holding capacity suggests that quality remains the same and light color is probably related to other factors.

A statistical analysis of nonlinear regression models for different treatments for layers.

As the cost of research increases, mathematical models become valuable tools to answer research questions. A major application of mathematical modeling is accurate estimation of production performance, growth, and feed consumption for poultry research and production. There are many ways that a given data set can be analyzed, and different models have been proposed to fit those curves. To explore the models available, data were investigated from a study on the effects of a series of balanced dietary protein levels on egg production and egg quality parameters in lying hens from 18 to 74 wk of age. Forty eight pullets were assigned to each of 3 different protein levels. The results clearly demonstrated that balanced dietary protein level was the limiting factor for body weight (BW), average daily feed intake (ADFI), egg weight, and egg production. To test differences of fitted curves, the sum of squared reduction test is used. Using a unique data set with data from individual hens, 6 commonly used models were fitted to hen performance technical data. The resulting statistical inferences from using individual and pooled data were compared. There are only differences in using individual or grouped data in fitting nonlinear models to laying hen response data. For the most important response variables, hen-day egg production, and feed intake, predicted responses are within 0.12 and 0.65%, respectively, throughout the production cycle.

Abductive statistical methods improve the results of calibration curve bioassays: An example of determining zinc bioavailability in broiler chickens.

In this paper, we discuss the theory behind calibration curve experiments and their application to a zinc (Zn) bioavailability study with broiler chickens. Seven replicates of 16 male commercial broiler chicks were fed starter diets for 14 days. Six diets had different levels of a potential Zn source and one was a positive control with standard industry levels of Zn for comparison. Four commonly used methods of calculating bioavailability means and confidence intervals (CI) from a calibration curve (standard curve) experiment to estimate the bioavailability of a new zinc source in broiler chickens were compared. The methods compared were the following: 1) the Counter-Intuitive Method uses a multiple-range test to compare unknown test and standard samples; 2) the Intuitive Method uses standard linear regression and inverts the equation to predict Zn bioavailability for each replicate of test samples; 3) the Abductive Method uses Graybill's Equation, based on theory and observation, to estimate CI's; and 4) the Sophistic Method uses reverse regression, and calculates Zn bioavailability values directly from the equation. The Counter-Intuitive Method only gives information about which standards the test samples are, or are not, significantly different from respectively (average available Zn not predicted). The Intuitive Method ignores error about the standard curve and theoretically cannot estimate the CI directly ( X ¯ ± SEM  = 107.5 ± 15.8 mg Zn/kg). The Sophistic Method underestimates and overestimates the test sample mean values above and below the mean of the standards, respectively ( X ¯  = 96.6 mg Zn/kg). The Abductive Method has an advantage over the other methods: The mean prediction estimation is consistent with theory (107.5 ± 6.1 mg Zn/kg; X ¯ ± SEM ). When test or "unknown" samples are near the mean of the standard samples, the CI is smaller than when near the extremes of the calibration curve. When calibration curve error is small (R 2 > approximately 0.95), there is little advantage to using the Abductive Method, but when calibration curve error is larger, as in many bioassays with growing animals, the Abductive Method improves the accuracy of the CI calculations. The Abductive Method was used to demonstrate the influence of the number of replicate samples on experimental power and cost.

Properties of the cuticular proteins of Anopheles gambiae as revealed by serial extraction of adults.

How cuticular proteins (CPs) interact with chitin and with each other in the cuticle remains unresolved. We employed LC-MS/MS to identify CPs from 5-6 day-old adults of Anopheles gambiae released after serial extraction with PBS, EDTA, 2-8M urea, and SDS as well as those that remained unextracted. Results were compared to published data on time of transcript abundance, localization of proteins within structures and within the cuticle, as well as properties of individual proteins, length, pI, percent histidine, tyrosine, glutamine, and number of AAP[A/V/L] repeats. Thirteen proteins were solubilized completely, all were CPRs, most belonging to the RR-1 group. Eleven CPs were identified in both soluble fractions and the final pellet, including 5 from other CP families. Forty-three were only detected from the final pellet. These included CPRs and members of the CPAP1, CPF, CPFL, CPLCA, CPLCG, CPLCP, and TWDL families, as well as several low complexity CPs, not assigned to families and named CPLX. For a given protein, many histidines or tyrosines or glutamines appear to be potential participants in cross-linking since we could not identify any peptide bearing these residues that was consistently absent. We failed to recover peptides from the amino-terminus of any CP. Whether this implicates that location in sclerotization or some modification that prevents detection is not known. Soluble CPRs had lower isoelectric points than those that remained in the final pellet; most members of other CP families had isoelectric points of 8 or higher. Obviously, techniques beyond analysis of differential solubility will be needed to learn how CPs interact with each other and with chitin.