Influence of Grain Processing and Dietary Protein Degradability on Nitrogen Metabolism, Energy Balance and Methane Production in Young Calves

Abstract

Crossbred (Bos taurus×Bos indicus) calves were used from birth till 14 weeks of age to evaluate three sources of protein that differed in ruminal degradability viz. groundnut cake alone (HD) or in combination with cottonseed meal (MD) and meat and bone meal (LD), when fed along with two sources of non-structural carbohydrates viz. raw (R) and thermally processed (P) maize. Twenty four new born calves were arranged in six groups in a 3×2 factorial design and fed on whole milk up to 56 d of age. All the different calves received calf startes along with green oats (Avena sativa) from 14 d of age onwards free-choice. A metabolism trial of 6 d starters duration, conducted after 90 d of experimental feeding, revealed greater (p<0.05) digestibility of DM, OM, total carbohydrates, NDF and ADF in calves fed on the P diets than on the R diets promoting greater (p<0.05) metabolizable energy intake. The digestibility of NDF was higher (p<0.01) on LD diets where as calves on MD diets exhibited significantly lower digestibility of ADF (p<0.01). The retention of nitrogen per unit metabolic body size was significantly (p<0.05) higher on the LD-P diet than on the diet HD-P which, in turn, was higher (p<0.05) than that of HD-R. Nitrogen retention as percentage of intake was significantly greater (p<0.05) on LD-P than on LD-R diets (52.2 vs. 36.4%). Also, P fed calves utilized nitrogen more efficiently than the R fed as shown by retention of significantly greater proportions of intake (47.4 vs. 40.9%) and absorbed (65.8 vs. 59.5%) nitrogen. Calorimetric evaluation of the diets through open-circuit respiration chamber revealed that the dietary treatments had no impact on methane production by calves. The intake of DE and ME was improved (p<0.01) because of maize processing resulting in greater (p<0.01) retention of energy. The protein degradability exerted no influence on the partitioning or retention of energy. A significant interaction between cereal and protein types was evident with respect to retention of both nitrogen (p<0.01) and energy (p<0.05). In conclusion, no discernible trend in the influence of cereal processing was apparent on the dietary protein degradability, but the positive effect of cereal processing on energy retention diminished with the increase in dietary undegradability.

Effect of Varying Levels of Dietary Ruminal Undegradable Protein on Feed Consumption and Growth Performance of Growing Kajli Lambs

“…Unless optimal ratio between RUP and RDP is ensured, the optimal rumen ecosystem activity cannot be obtained. In our study, decreasing DM, CP, NDF and ADF digestibilities trend was noticed with increasing Findings of the current study indicated that higher dietary RUP resulted in decreased N excretion and were concordant with findings of other workers (Pattanaik et al, 2003;Paengkoum et al, 2004) who reported an increase in N balance and reduction in N excretion when high dietary RUP was fed to ruminants. In the present study, RUP55 diet excreted less urinary N (P<0.05) than RUP25, RUP35 and RUP45 diets.…”

“…The urea can be recycled into the rumen and becomes again available for conversion into microbial protein. Diets having an increased RUP concentration resulted in improved N balance and decreased N excretion relative to intake (Pattanaik et al, 2003;Reynal and Broderick, 2005). An appropriate balance between ruminally degradable and undergradable protein fractions can assure sufficient amount of required AAs balance for intestinal absorption to match animal's requirement.…”

Effect of Varying Dietary Rumen Undegraded Protein on Nutrient Intake, Nutrient Digestibility and Production Performance in Early Lactating Crossbred Cows

“…In another study (Kumar et al, 2005) CP, DM and NDF digestibility increased with increasing dietary RUP of CP from 41 to 48%. Similar findings were also reported by Pattanaik et al (2003) in calves where NDF digestibility enhanced by increasing RUP level from 45 to 51% of dietary CP. This increased CP and NDF digestibility might be attributed to decreased dietary RDP which ultimately leads to increased ruminal pH (Bodine et al, 2000).…”

“…In Holstein Friesian cows, different dietary RDP levels based on soybean meal resulted in same excretion of N in milk and feces but increased urinary N in early to mid-lactation period (Castillo et al, 2001). Similarly, increased N retention was also observed in calves when dietary RUP level increased from 45 to 51% of CP (Pattanaik et al, 2003). The reduced urinary N excretion by animals fed diets containing higher level of RUP might reduce ruminal ammonia.…”

Ruminal dynamics of ad libitum feeding in buffalo bulls receiving different level of rumen degradable protein

“…Highest N balance in bulls fed C diet was due to its low RDP level (50%). Higher N retention in crossbred calves fed low RDP diet than those fed high RDP diet was reported by Pattanaik et al (2003). Linear decrease in fecal and urinary N was due to linear decrease in N intake.…”