A dynamic mathematical model was developed to describe the reproductive process in beef cattle production systems and to simulate individual cow reproductive performance while generating results for the herd, based on the body condition score (BCS) at calving and age at sexual maturity. The model is empiric and dynamic, containing deterministic and stochastic elements. The model was developed based on the relationship between BCS and postpartum interval for lactating cows; for heifers and non-lactating cows, the conception rate was based […]

A bio-economic model was developed to calculate costs and revenues to obtain economic values (EV) for performance traits of beef cattle in production systems in Brazil. Performance records, economic and biologic parameters were obtained from a Nelore breeding herd. Two production systems: complete breeding cycle (CbcR) and cow-calf (Cc) were simulated using a deterministic and static model. Costs, revenues and the annual profits were calculated using Excel® to obtain the economic values for weaning weight (WW), mature weight (MW), pregnancy […]

This experiment was carried out to estimate the crude protein and metabolizable energy requirements for maintenance and gain of 384 females of Japanese quails from 1 to 12 days of age. A completely randomized design with four treatments, with six replicates of ten birds each, was used. The treatments were: T1 = basal diet (BD) with 28% CP and 2,900 kcal AMEn ad libitum; T2 = 80%; T3 = 60% and T4 = 40% of ad libitum (close to maintenance). […]