Masoud Norozi-ِDeeyarjan; ali assadi-alamouti; Ahmad Afzalzadeh; mohsen danesh mesgaran
Volume 19, Issue 4 , March 2018, , Pages 751-764
Abstract
This study examined the effects of partial replacement of soybean meal (SBM) with heat-treated soybean meal (HSBM) in heat-stressed cows. 32 multiparous Holstein cows (DIM = 110 ± 20; milk yield = 40 ± 4.1 kg) were used in a complete block randomized design with a 2×2 factorial arrangment ...
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This study examined the effects of partial replacement of soybean meal (SBM) with heat-treated soybean meal (HSBM) in heat-stressed cows. 32 multiparous Holstein cows (DIM = 110 ± 20; milk yield = 40 ± 4.1 kg) were used in a complete block randomized design with a 2×2 factorial arrangment of treatments. Treatments included two dietary crude protein levels (i.e. 17 and 15.5%) each combined with HSBM partially replaced for SBM. The experiment was conducted in two periods of 28 days with the last seven days for sampling and collection of data of tempreature, nutrient intake and digestibility and blood variables. Average THI showed that cows were in mild heat stress (70.60 and 71.50 for periods 1 and 2, respectively)(p > 0.05). Diets with 15.5% CP and based on HSBM increased intakes of dry and organic matter (p < 0.05); however, this was not observed in diets with 17% CP. Milk yiled and composition, apparent nutrient digestibility and blood variables were unaffected (p > 0.05). Butyric and isovaleric acid were increased in cows received HSBM (p < 0.05); however, level of CP had no effect. Results showed that feeding HSBM in diets with 15.5% CP could be regarded as a nutritional sterategy for improving DM intake of mild heat-stressed cows.