Compares the effects of noug meal, Trifolium tembense hay and urea, fed in different combinations as supplements to wheat or teff straws, on feed intake and growth rate of crossbred heifers

Butterworth, M.H.

Olayiwole, M.B.

Olorunju, S.A.S.

Sayers, A.R.

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The effect of supplementing cereal straws with urea, Trifolium hay and noug meal on feed intake and liveweight gain of growing crossbred heifers M.B. Olayiwole1, M.H. Butterworth2, A.R. Sayers3, and S.A. S. Olorunju1 1National Animal Production Research Institute, Ahmadu Bello University, P.M.B. 1096, Zaria, Nigeria 2Nutrition Unit and 3Computer Unit, ILCA, P.O. Box 5689, Addis Ababa, Ethiopia Summary DIFFERENT COMBINATIONS of urea, Trifolium hay and noug meal were individually fed to growing crossbred heifers as supplements to diets based on teff or wheat straw. The rations given were isonitrogenous, and crushed maize was added to ensure that energy was not limiting. The aim of the experiment was to compare the supplements as sources of dietary nitrogen (N). Total dry matter (DM) intake increased when noug was included in the rations and deceased when urea was fed. Trifolium hay increased the intake of rations based on wheat straw but did not have any effect on the intake of teff-based rations. Weight gains increased when Trifolium hay was included in the rations. The addition of urea to rations that did not contain noug increased the rate of weight gain, and this was further increased when noug was added. All differences were significant at P<0.05. The results of the study indicate that acceptable rates of weight gain can be obtained in growing dairy heifers by feeding rations based on cereal crop residues supplemented with small quantities of maize and urea, and protein from a legume or oilseed meal. Introduction Grazing animals in the Ethiopian highlands are subject to widely varying levels of nutrition, and during the dry season a large proportion of their diet is made up of cereal crop residues. These are high in lignocellulosic complexes and consequently of low digestibility, and as a result they are consumed in only limited quantities by ruminants. Cereal crop residues are often less than 50% digestible, and intake is usually 50 g/kg LW0.75 or less (Mosi and Butterworth, 1985). However, supplementation with protein or non-protein nitrogen (NPN) can increase both digestibility and intake of the complete diet. Clovers endemic to the Ethiopian highlands, such as Trifolium tembense, have been used in this way (Mosi and Butterworth, 1985), as has the residue of the oilseed noug (Guizotia abyssinica) after extraction (Butterworth and Mosi, 1985). Grown as an alternative to arable crops, clovers have the additional advantage of improving soil fertility through N fixation. The objective of the work described in this article was to compare the effects of noug meal, Trifolium tembense hay and urea, fed in different combinations as supplements to wheat or teff straws, on feed intake and growth rate of crossbred heifers. Materials and methods The study was carried out at ILCA headquarters in Shola, Addis Ababa, at an altitude of 2380 m. Rainfall during the 4 years prior to the experiment averaged 900 mm per annum. Thirty-six 1- to 2-year-old Holstein x Zebu heifers were used in the experiment. They had an average liveweight of 203 kg at the beginning of the experiment and were divided into 12 groups according to weight and age. The groups were randomly allocated one of 12 diets based on wheat or teff straw fed ad libitum and supplemented with different combinations of urea, Trifolium hay and noug meal. All rations were formulated so as to be isonitrogenous at 1.2% N. However, due to variations in the animals' consumption of the straw, which was offered ad libitum, the mean N content of supplemented rations was 1.21 ± 0.08% N (7.55 ± 0.52% CP). Urea was sprinkled on the straw, which was then stored in polythene bags for approximately 16 hours before feeding. Supplements were given as a separate meal which was completely consumed before straw was offered ad libitum. As the main aim of the experiment was to evaluate the supplements as sources of N, it was undesirable for energy to be limiting. Each ration was therefore supplemented with enough crushed maize grain to satisfy energy requirements for a daily weight gain of 250 g (Agricultural Research Council, 1980). Fresh water and a complete mineral lick were always available, and bone meal and anhydrous sodium sulphate were added to the feed daily. The amounts of feed offered and refused were recorded daily, and samples were analysed using methods described in AOAC (1980) and Goering and van Soest (1970). Experimental animals were assigned at random to individual feeding pens. A standardisation period of 14 days was followed by an experimental period of 98 days. Animals were weighed every 14 days and rectal palpation was carried out to monitor ovarian activity. Results and discussion The chemical composition of the various feeds used is given in Table 1. Except for noug meal, which was relatively low in N, the values shown are similar to those found by Mosi and Butterworth (1985) and Butterworth and Mosi (1985). Table 1. Composition of feeds expressed as percentage of dry matter.   Tef straw Wheat straw Trifoliumhay Noug meal Maize grain Urea Organic matter 92.1 93.2 89.5 89.5 98.1 – Nitrogen 0.86 0.74 2.5 4.5 1.7 45 NDF 73.5 72.2 44.4 31.1 15.9 – Hemicellulose 29.3 17.9 7.8 5.7 11.3 – ADF 44.2 54.3 36.6 25.4 4.6 – Cellulose 40.0 48.4 31.8 20.1 3.6 – Lignin 4.2 5.9 4.8 5.3 1.0 – Ash 7.9 6.8 10.5 10.5 1.9 –   Daily consumption of individual feed components in the different rations is given in Tables 2 and 3. Although there were substantial differences in the intake of straw among the different diets, they were not significant. This was to be expected in view of the similarity in the NDF content of the two straws (Mertens, 1973). Table 2. Daily consumption of individual dietary constituents of teff-based diets.   T T + U T + NM T + Trif. T+Trif.+U T+Trif. + NM SD Teff straw (kg) 3.79 3.31 4.26 3.35 3.39 3.85 ±1.04 Maize grain (g) 498 515 337 337 351 353 ±36 Trifolium hay (g) – – – 500 501 452 ±117 Noug meal (g) – – 412 – – 434 ±140 Urea (g) – 21.4 – – 9.2 – ± 2.5 T = teff straw; U = urea; NM = noug meal; Trif. = Trifolium hay. Table 3. Daily consumption of individual dietary constituents of wheat-based diets.   W W+U W+NM W+Trif. W+Trif.+U W+Trif.+NM SD ± Wheat straw (kg) 3.00 2.69 3.79 3.30 2.84 3.74 1.12 Maize grain (g) 648 652 394 351 381 307 131 Trifolium hay (g) – – – 629 496 428 66 Noug meal(g) – – 382 – – 347 27 Urea (g) – 24.5 – – 9.2 – 2.2 W = wheat straw; for U, NM and Trif. see Table 2. Table 4 gives the total consumption of dry matter. Analysis of variance of the pooled data showed that the intake of rations containing urea was significantly lower than that of rations without urea or with noug meal supplements. This may have been due to the fact that urea was fed at one time rather than throughout the day. The importance of efficient allocation of feed supplies over the 24-hour period has recently been emphasised by Sniffen and Robinson (1984), and it is evident that feeding strategy is particularly important when considering the supplementation of diets based on crop residues.     Table 4. Pooled mean values of total DM intake (g/kg LW0.75) by animals fed different combinations of cereal crop residues, Trifolium hay, urea and noug meal.   –Trif. +Trif. SE Wheat straw 71.5a 79.5b ±1.75 Teff straw 81.5b 81.8b ±1.75 No urea or no noug Urea Noug SE 72.2a 71.7a 86.8b ±1.51 Note: For each sub-table, means followed by the same letter are not significantly different (P<0.05). There was a significant interaction between Trifolium hay and the straw fed. When no Trifolium hay was fed total DM intake was higher on teff-based diets than on wheat-based diets, but whenTrifolium hay was included there were no significant differences in intake between the straws. The increased DM intake associated with noug meal was consistent with the results obtained by Butterworth and Mosi (1985), which showed that supplementing cereal crop residues with noug meal increased both intake and digestibility of the diet when fed to sheep. Pooled results for weight gains (g/day) are given in Table 5; no significant differences in growth rate could be attributed to straw type. The inclusion of Trifolium hay in the rations significantly (P<0.05) increased the daily rate of gain. This finding is consistent with the results obtained by Mosi and Butterworth (1985). Animals fed urea gained more weight than those fed rations containing straw andTrifolium hay only; the weight gain of animals fed noug meal was greater than that of those fed straw and Trifolium hay with or without urea (P<0.05). Table 5. Pooled mean values of weight gain (g/day) by animals fed different combinations of cereal crop residues, Trifolium hay, urea and noug meal. –Trif. + Trif. SE No urea ornoug Urea Noug S E 133a 227b ±25.2 72a 179b 289c ±30.8 Note: Means followed by the same letter are not significantly different (P<0.05). Table 6 shows that the marked effect of Trifolium was not matched by any increase in ruminal ammonia concentration. Both urea and noug caused marked increases in ruminal ammonia levels, from 6–8 mg/ 100 ml to 10–12 mg/100 ml. Only in the case of noug was this associated with higher intake; weight gains of animals fed noug-supplemented diets were much higher than those of animals fed urea-supplemented diets.   Table 6. Effect of diet on ruminal ammonia concentration (mg/100 ml). Basal component1 Alone With urea With noug Teff straw 8.52 11.0 10.2 Teff straw + Trifolium 7.0 11.6 11.2 Wheat straw 5.5 12.3 10.6 Wheat straw + Trifolium 8.1 9.3 10.6 1 All diets contained about 10% crushed maize. 2 Each entry is a mean of three sampling times. These results indicate that addition of either urea or noug meal increased the weight gain of animals fed straw with or without Trifolium. The increased DM intake associated with Trifolium hay andnoug meal might be due either to their providing bypass protein or to their increasing the availability of amino acids, peptides or branched-chain fatty acids in the rumen, which in turn would increase the yield of rumen microbial protein (van Soest,1982). No significant treatment effects on ovarian function were observed. Conclusions Satisfactory growth rates were obtained in crossbred dairy heifers by feeding cereal crop residues supplemented with shall amounts of maize and urea and additional protein. The protein could be supplied in the form of either legumes grown in an alley-farming system or on fallow land, or locally available oilseed meals or similar protein concentrates. References Agricultural Research Council. 1980. The nutrient requirements of ruminant livestock. Commonwealth Agricultural Bureaux, Farnham Royal, U.K. 351p. AOAC (Association of Official Analytical Chemists). 1980. Official methods of analysis (13th Edition). AOAC, Washington, D.C. 1018p. Butterworth M H and Mosi A K. 1985. The intake and digestibility by sheep of oat straw and maize stover fed with different levels of noug (Guizotia abyssinica) meal. Anim. Feed Sci. Technol. Goering H K and van Soest P J. 1970. Forage fiber analysis apparatus, reagents, procedures and some applications. Agriculture Handbook No. 379. Agricultural Research Service, United States Department of Agriculture. 20p. Mertens D R. 1973. Application of theoretical mathematical models to cell wall digestion and forage intake in ruminants. PhD thesis, Cornell University. 218p. Mosi A K and Butterworth M H. 1985. The voluntary intake and digestibility of cereal crop residues and legume hay for sheep. Anim. Feed Sci. Technol. Sniffen C J and Robinson B H. 1984. Nutritional strategy. Can. J. Anim. Sci. 64: 529–542. van Soest P J. 1982. Nutritional ecology of the ruminant. O & B Books Inc., Corvallis, Oregon. 375p.  

The effect of supplementing cereal straws with urea, trifolium hay and noug meal on feed intake and liveweight gain of growing crossbred heifers

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The effect of supplementing cereal straws with urea, trifolium hay and noug meal on feed intake and liveweight gain of growing crossbred heifers

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