ABSTRACT
In the last decade, advances in Brazilian hay production showed that the country has the potential to produce bulky dehydrated fodder. For many years, the Brazilian hay production scientific knowledge had been based on temperate climate species, even though the best hay material are tropical grasses, as Tifton 85 Bermudagrass. Researches that focused on the comprehension of yield systems, biochemical processes, physiology, composition, and nutritional quality of tropical species under dehydration and conservation have become important to hay yield in Brazil. Therefore, this literature review aimed to discuss the hay research contribution in tropical conditions and its reflex on the production and commercialization of hay in Brazil. This review was based on database research with key-words defined in a period between 1960 and 2021, which resulted in 33 articles. Each article had the strengths and weaknesses, opportunities, and threats classified according to the SWOT matrix. Articles related to the haymaking system with tropical forage and the effects on nutritional value, sanitary quality, and factors that influence the dehydration period in the field and storage were listed in this paper. Based on the literature, the conclusion is that Brazil has elevated hay yield potential with high nutritional and sanitary quality of tropical species due to the weather conditions that allow fast dehydration and, also, the availability of residual wastewater as fertilization and machinery appropriated. Brazilian haymaking and commercialization are in an expansion process with economic return as national and international trade. Further challenges: to obtain a constant annual hay supply and the transport viability to markets distant from the production center.
ABSTRACT
The present study aimed at evaluating the intensity of Tifton 85 conditioning using a mower conditioner with free-swinging flail fingers and storage times on dehydration curve, fungi presence, nutritional value and in vitro digestibility of Tifton 85 bermudagrass hay dry matter (DM). The dehydration curve was determined in the whole plant for ten times until the baling. The zero time corresponded to the plant before cutting, which occurred at 11:00 and the other collections were carried out at 8:00, 10:00, 14:00, and 16:00. The experimental design was randomised blocks with two intensities of conditioning (high and low) and ten sampling times, with five replications. The high and low intensities related to adjusting the deflector plate of the free iron fingers (8 and 18 cm). In order to determine gas exchanges during Tifton 85 bermudagrass dehydration, there were evaluations of mature leaves, which were placed in the upper middle third of each branch before the cutting, at every hour for 4 hours. A portable gas analyser was used by an infrared IRGA (6400xt). The analysed variables were photosynthesis (A), stomatal conductance (gs), internal CO2 concentration (Ci), transpiration (T), water use efficiency (WUE), and intrinsic water use efficiency (WUEi). In the second part of this study, the nutritional value of Tifton 85 hay was evaluated, so randomised blocks were designed in a split plot through time, with two treatments placed in the following plots: high and low intensity of cutting and five different time points as subplots: cutting (additional treatment), baling and after 30, 60, and 90 days of storage. Subsequently, fungi that were in green plants as well as hay were determined and samples were collected from the grass at the cutting period, during baling, and after 30, 60, and 90 days of storage. It was observed that Tifton 85 bermudagrass dehydration occurred within 49 hours, so this was considered the best time for drying hay. Gas exchanges were more intense before cutting, although after cutting they decreased until ceasing within 4 hours. The lowest values of acid detergent insoluble nitrogen were obtained with low conditioning intensity after 30 days of storage, 64.8 g/kg DM. The in vitro dry matter of Tifton 85 bermudagrass did not differ among the storage times or the conditioning intensities. There was no fungi present in the samples collected during the storage period up to 90 days after dehydration, with less than 30 colony forming units found on plate counting. The use of mower conditioners in different intensities of injury did not speed up the dehydration time of Tifton 85.