Economic losses caused by the use of low-efficacy anthelmintic drugs in growing heifers.

The aim of this study was to compare the economic revenue related to the use of low- or high-efficacy anthelmintic drugs within suppressive or strategic schemes of treatment in growing heifers. Heifers raised in a semi-intensive grazing system in southern Brazil were used. Levamisole and ivermectin were selected as the high- and the low-efficacy drugs, respectively, based on a previous efficacy test. Subsequently, these drugs were used within strategic (Strat; four times per year) or suppressive (Supp; once a month) treatment regimens in the heifers, and their liveweight and eggs per gram of feces counts were monthly evaluated during a 13-month period. The total costs of the treatments and their cost-benefit ratio in regard to liveweight gain were calculated. Final mean liveweight gains (kg) observed were 126.7 (Strat-Low), 133.6 (Supp-Low), 141.3 (Strat-High), 142.9 (Supp-High), and 125.8 (Control). Treatments with a high-efficacy drug resulted in monetary gains of US$ 19.56 (Strat-High) and US$ 14.98 (Supp-High), but Supp-Low and Strat-Low treatments caused economic losses. Total cost of the efficacy test (US$ 374.79) could be paid by the additional liveweight gain of 20 heifers from the Strat-High group. These results showed that it would be preferable not to treat the heifers against GIN if compared with treating them with a low-efficacy drug. In addition, we showed that the use of four treatments per year with a high-efficacy drug-selected by efficacy test-resulted in a profitable management to control GIN in growing heifers raised in a semi-intensive gazing system in southern Brazil.

Desenvolvimento vegetativo e reprodutivo em gladíolo / Vegetative and reproductive development in gladiolus

A caracterização das etapas ou fases do ciclo de desenvolvimento das culturas agrícolas é importante para realização de práticas de manejo e, para o gladíolo, essas etapas ainda não foram bem caracterizadas em cultivos a campo no Rio Grande do Sul. Este trabalho teve como objetivo determinar a duração das fases vegetativa e reprodutiva do ciclo de desenvolvimento e as relações entre estas com a emissão de folhas em cultivares de gladíolo. Dois experimentos foram realizados a campo, em Santa Maria, RS, um na primavera/verão 2010/11, com as cultivares: 'Priscila', 'Peter Pears', 'Sunset', 'T704', 'Traderhorn', 'Rose Supreme' e 'Jester' e outro no outono/inverno 2011 com as cultivares 'T704', 'Traderhorn' e 'Jester'. O delineamento experimental foi inteiramente casualizado com duas repetições de cinco plantas de cada cultivar. Foram determinadas as datas do espigamento e final de florescimento e o ciclo de desenvolvimento foi dividido em duas fases: vegetativa (do plantio ao espigamento) e reprodutiva (do espigamento ao final do florescimento). Os resultados indicaram que a duração da fase vegetativa é a que determina a duração do ciclo total da parte aérea e que a duração da fase vegetativa é influenciada pela velocidade de emissão das folhas e pelo número final de folhas. Assim, cultivares precoces têm maior velocidade de emissão de folhas e menor número final de folhas do que cultivares tardias.

The characterization of the developmental phases of agricultural crops is important for management practices and for gladiolus in the field this characterization has not been made in Rio Grande do Sul State. The goal of this study was to determine the duration of vegetative and reproductive phases of the developmental cycle, and the relationships between them and with leaf appearance in gladiolus cultivars. Two field experiments were conducted in Santa Maria, RS, Brazil, one during the Spring/Summer 2010/11 with the cultivars 'Priscila', 'Peter Pears', 'Sunset', 'T704', 'Traderhorn', 'Rose Supreme' and 'Jester', and another during the Fall/Winter 2011 with the cultivars 'T704', 'Traderhorn' and 'Jester'. The experimental design was a completely randomized with two replications of five plants per cultivar. The date of heading and end of flowering was determined and the developmental cycle was divided into vegetative (from planting to heading) and reproductive (from planting to and of flowering). Results showed that the duration of the vegetative phase determines the duration of the developmental cycle and the duration of the vegetative phase is affected by leaf appearance rate and by final leaf number. Thus, early cultivars have greater leaf appearance rate and lower final leaf number than late cultivars.