Effect of Level of Crude Protein and Use of Cottonseed Meal in Diets Containing Cassava Chips and Rice Straw for Lactating Dairy Cows

Abstract

The effects of different levels of crude protein (CP) and cottonseed meal replacing for soybean meal in cassava chips and rice straw-based diets for mid-lactating cows (100-150 day in milk [DIM]), were studied using 32 multiparous Holstein Fresian crossbred dairy cows. Diets containing 10.5, 12.5, 13.7, 14.4% CP of the rations and 0, 12.1, 14.9, 17.8% cottonseed meal were fed to cows for 60 days. Thirty two cows were randomly divided into four dietary treatments using a Randomized complete block design. Four dietary treatments were offered in the form of total mixed ration (TMR) with concentrate to roughage (chopped rice straw) at 60:40 and offered ad libitum. Dry matter (DM) and neutral detergent fiber (NDF) intakes tended to linearly increase with increasing dietary CP levels. Intakes and digestibility of crude protein increased linearly with increasing dietary CP level (p<0.01). Crude protein digestibility of the 10.5% CP diet was lower (p<0.05) than that in diets with higher levels of CP, while there were no significant differences among the other three levels of CP (12.5, 13.7 and 14.4%). Daily milk yield tended to increase with increased CP from 10.5 to 14.4%. Income over feed in terms of US$/kg of milk increased with increased CP from 10.5 to 13.7% and decreased when the CP level was higher than 13.7% (quadratic effect p<0.09). Milk composition was not significantly affected by increasing level of CP, however there were relatively high contents of protein and fat among treatments. The proportion of milk-urea N (MUN), ammonia-N (NH 3 -N) and bloodurea N (BUN) were closely correlated and increased linearly with increasing CP levels (p<0.01). Balanced diet was found in diet containing 12.5 and 13.7% CP of the rations when BUN and MUN were used as indicators of the protein to energy ratio in the diet. Conclusions can be made that increasing dietary CP levels from 10.5 to 13.7% using cottonseed meal as the main source to completely replace soybean meal was beneficial to cows consuming rice straw and cassava chips based-diets. Increasing the CP level above 13.7% of total ration did not additionally improve milk yield and composition or net income.

Responses of milk urea nitrogen content to dietary crude protein level and degradability in lactatingHolsteindairy cows

“…The MUN values were significantly affected by dietary treatments (P < 0.01), with the lowest values in cows fed diet A, followed by diets B and C, and the highest in cows fed diet D. The MUN values increased with CP levels. The observation was consistent with some studies (Davidson et al, 2003;Groff and Wu, 2005;Promkot and Wanapat, 2005), while Flis and Wattiaux (2005) found that a 1% change in the dietary protein level did not cause a significant change in the MUN content.…”

Effects of feeding different levels of corn steep liquor on the performance of fattening lambs

“…The increased blood urea‐N concentration in the lambs fed CSL was in association with the higher ruminal ammonia‐N in them (Table ). Findings of Promkot and Wanapat () and Azizi‐Shotorkhoft et al. () have also shown a positive correlation between blood urea‐N and ruminal ammonia‐N concentrations.…”

Effect of carbohydrate sources and cotton seed meal in the concentrate: II. Feed intake, nutrient digestibility, rumen fermentation and microbial protein synthesis in beef cattle

“…Furthermore, cottonseed meal, an important rumen undegradable protein source (49 g/kg DM; Shibanda et al 1992), could be beneficial for improvement of animal performance. Promkot and Wanapat (2005) concluded that using cottonseed meal as the main source to completely replace soybean meal was beneficial to cows consuming rice straw and cassava chips-based diets. This agreed with Wanapat et al (1996) who found that cottonseed meal supplementation significantly increased milk yield of dairy cattle fed rice straw.…”