No levantamento que envolveu 972 criatórios de cavalos, com número igual ou maior que três cavalos por criatório em 28 estados norte-americanos, foram coletadas 8.417 amostras de fezes de cavalos e submetidas à cultura para testar a presença de Salmonella spp. Os criatórios foram classificados como positivos se pelo menos uma amostra testada fosse positiva para Salmonella spp. As percentagens de criatórios positivos foram calculadas de acordo com o manejo e outros fatores (coletados por meio de questionários) que hipoteticamente estavam relacionados com Salmonella spp em fezes de cavalos. Um modelo de regressão logística foi ajustado às observações de forma a identificar fatores associados com Salmonella spp nas fezes de cavalos nos criatórios. A probabilidade de o criatório ser positivo para Salmonella spp aumenta com o número de cavalos do criatório. Além disso, os seguintes fatores foram identificados como associados ao aumento da probabilidade do criatório ser positivo para Salmonella spp: cavalos utilizados essencialmente para reprodução, deficiência na higiene do criatório e adição de novos cavalos sem respeitar as normas de quarentena.

In a cross-sectional national study that included 972 operations with > 3 horses on 1/1/98 in 28 states in the USA, 8,417 fecal specimens were collected from horses and cultured to test for the presence of Salmonella spp. Operations were characterized as Salmonella spp-positive if at least one fecal specimen tested positive for Salmonella spp. Percentages of Salmonella spp-positive operations were computed by management and other factors (collected from operation-level questionnaires) that were hypothesized to be related to fecal shedding of Salmonella spp. A logistic-regression model was constructed to identify factors associated with horses’ shedding Salmonella spp in feces on an operation. The odds of an operation being Salmonella spp positive increased as the number of resident horses increased. In addition, the following factors were found to be associated with increased odds of an operation being Salmonella spp positive: horses were used primarily for breeding; operation cleanliness was characterized as poor by the data collector; and new resident equids had been added to the operation without routine quarantine.

A produção de dejetos em granjas de crescimento e terminação de suínos nos Estados Unidos foi avaliada utilizando dados de 184 granjas participantes de um estudo nacional de 1995 do "United States National Animal Health Monitoring System". Dois métodos foram usados: um considerando que suínos produzem 8,4% do seu peso corporal de dejetos por dia e o outro usando a diferença entre o alimento ingerido e o ganho de peso como um indicador para o estudo da produção de esterco. Através desse último procedimento, desenvolveu-se uma função de produção.

Manure production on grower/finisher swine operations in the United States was examined using data from 184 grower/finisher swine operations that participated in the United States National Animal Health Monitoring System's 1995 National Swine Study. Two methods were used: one, assuming that pigs produced 8.4% of their body weight in manure each day; another using the difference between feed fed and weight gained as a proxy variable to study manure production. Using this latter approach, a production function was developed. The function exhibited diminishing returns to scale when food waste was not fed to pigs, but constant returns to scale when food waste was included in their diets. The difference between feed fed and weight gained was lower on operations that restricted entry to employees only.

A mortalidade de suínos, durante um período de 6 meses, variou de 0 a 12% em 53 granjas de crescimento/terminação, que participam do "United States National Animal Health Monitoring System 1995 National Swine Study". Vinte e seis (49,1%) granjas tiveram <2% de mortalidade e 27 (50,9%) tiveram índices >2%. Nove (17,0%) granjas apresentaram mortalidade >4%. A análise pelo teste de Fisher revelou que as granjas que adotavam o sistema "all-in, all-out" eram significativamente mais propensas a apresentar índices <2% que as granjas com manejo contínuo, e que as granjas nas quais todos os suínos terminados eram oriundos de unidades pertencentes às próprias granjas eram significativamente mais propensas a ter mortalidade <2% que as granjas onde os animais (>1) provinham de outras origens. Granjas maiores (com mais de 900 animais entrando na fase de crescimento/terminação) adotavam com maior freqüência o manejo "all-in, all-out e tiveram menor percentual de mortalidade do que pequenas granjas. O diagnóstico de Salmonella em suínos terminados, realizado 12 meses antes da intervenção, foi associado ao aumento do percentual de mortalidade geral e diário.

For 53 grower/finisher-only swine operations that participated in the United States National Animal Health Monitoring System 1995 National Swine Study, mortality among finisher pigs ranged from 0 to 12.0% over a 6-month period. Twenty-six (49.1%) had <2% mortality, and 27 (50.9%) had >2% mortality. Nine (17.0%) operations experienced >4% mortality. Fisher's exact test revealed that operations with all-in all-out management were significantly more likely to have <2% mortality than operations with continuous management, and that operations where all finisher pigs came from farrowing units belonging to the operation (either on-site or off-site) were significantly more likely to have <2% mortality than operations where >1 grower/finisher pig came from another source. Larger operations (where >900 pigs entered the grower/finisher phase) practiced all-in, all-out management more frequently than smaller operations, and had a lower mean percent mortality than smaller operations. Diagnosis of Salmonella in finisher pigs performed at a laboratory or by a veterinarian in the 12 months prior to interview was associated with both increased percent mortality and increased percent mortality per day.