JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND MaataloustieteellinenAikakauskirja Voi. 56: 137—141 Rapeseed meal and urea as a protein source for growing bulls on alkali-treated straw-based feeding LIISA SYRJÄLÄ-QVIST and MIKKO TUORI Department of Animal Husbandry, University of Helsinki, SF-00710 Helsinki 71 Abstract. Between the ages of 3 1/2 and 10 months, 12 bulls took part in an experiment in which 1) Tower rapeseed meal or 2) urea plus rapeseed meal was used as a protein source in a diet based on dry alkali-treated straw. In group 1 the rapeseed meal composed 32 % of a concentrate mixture also containing barley, oats, molassed beet pulp and minerals. The average daily consumption of rapeseed meal was 1.2 kg/animal and it contributed 58 % of the digestible crude protein supply. In group 2 urea composed 2 % of the concentrate mixture and the average daily consumption was 84 g/animal. In this group urea contributed about 38 % and rapeseed meal 20 % of the digestible crude protein supply. The palatability of the concentrate mixture was good in both groups. The average daily intake of alkalitreated straw was 2.3 kg/animal or 0.77 kg dry matter/100 live weight kg. Treated straw was the only roughage received by the animals from the age of 6 months. Up to that age the animals also received hay, on average 840 g per animal and day. The average daily live weight gain in group 1 was 1072 g/animal and in group 2 it was 1111 g; the carcass weights in the respective groups were 169 kg and 176 kg, and the feed con- version rates were 4.08 f.u. and 4.16 f.u./kg live weight gain. The differences between the group were not significant (P > 0.05). Almost all the animals showed pathological changes in their inner organs, which may mean that alkali-treated straw sounds not to be suitable as the only roughage source for growing bulls. Introduction The use of straw as the only source of roughage for growing bulls has been restrict- ed by its low digestibility and high bulk. It has also been difficult to find an economical domestic source of valuable protein for straw-based feeding in countries like Fin- land, where cultivation is limited by the northern location. The development of methods for improving the energy value of straw and the production of new rapeseed varietes that are low in antinutritional sub- stances and can be cultivated in Finnish con- ditions as well has now made it possible to start rearing bulls on straw-based feeding. In Index words: rapeseed meal, urea, alkali-treated straw, growing bulls. 137 https://www.c-info.fi/en/info/?token=aGdJrR3Hdqs0IjAl.Mdfci788eMUYmvjF0RG82g.F9tfdviOFYm7bwDvPMgTEepTJNepMhzq0MbeFTX3ThUdoSTdNySMcyoxBuIIh6-_crY-9zR7AIvMFvSwjHL9vtBboLPZ9AasANOs0fjry7qZTI0eCnbf2qZqzow7iUg-zxVVWjmyKs3JoKAI5PBHOQ1tZZyQBCveNm15OHm7Tn-lTSQfw7MUO03NoeFgXGd98T03qZdg9hUPpbE this experiment the feed consumption, growth rate and health of the animals were investigated in bulls receiving alkali straw and rapeseed meal and urea together with grain concentrates. Experimental procedures The experiment was performed with 12 growing male bulls, 10 Ayrshire and 2 Friesi- an, which were divided by age, live weight and breed into two comparable groups. The animals mean age at the beginning of the ex- periment was 110 days and their mean weight 140 kg. The experiment lasted about 7 months, including an adaptation period of three weeks, in which the diet was gradually changed to that of the experimental regime. The experimental diets consisted of alkali- treated straw fed ad libitum, with hay during the first months of the experiment (Fig. 1), and a concentrate mixture consisting of bar- ley, oats, molassed beet pulp and a commer- cial mineral mixture. As an additional source of protein, one group received rapeseed meal (RSM group) and the other group urea + rapeseed meal (UREA group Table 1). The bulls were fed individually twice a day at a level which satisfied the energy and pro- tein demands of animals growing at a rate of 1000 g/day (DAENiCKEand Rohr 1974). They Table 1. Average percentages of different components in the concentrate mixture during the experi- ment. RSMGroups UREA Barley Oats 27.5 37 27.5 37 10Molassed beet pulp Rapeseed meal 10 32 II Urea 2 Minerals kg/f.u. 3 3 1.14 1.12 DCP, g/f.u. 170171 f.u. = feed unit = 0.7 starch equivalent DCP = digestible crude protein were weighed on two days at the beginning of the experiment and once a week during the experiment. The quantities of grain and the protein sources were adjusted as the weights increased, using weight intervals of 20 kg. The rapeseed meal used in the experiment was the Tower variety, in which the content of glucosinolates was only 0.2 % of dry mat- ter and that of tannins 1.3 °7o. The straw was mainly wheat straw. It was dry alkali-treated with a mobile machine (JF SP2000), in which the straw is chopped, and alkali solution added and mixed with the straw. The amount of NaOH added was 4.3 % of the dry matter of the straw. The unreacted base was determined by titration to pH 8 with 0.1 HCI. The residual NaOH averaged 0.96 % of the dry matter. The chemical analyses of the feeds were made by standard procedures. The feeding values of the concentrates and hay were cal- culated from the digestibility coefficients ob- tained from NJF Tables (Anon. 1969, Table 2), but the value for the treated straw was calculated from the results of a digestibility trial performed with adult rams. The digest- ibility coefficients of the different constit- uents of the treated straw were as follows: organic matter 70 %, crude protein 20 %, crude fat 50 °7o, crude fibre 85 % and N-free extract 60 %. The value number used cal- Fig. I. Live weight gain and feed consumption in different groups. 138 Table 2. The mean chemical composition and feeding value of the feeds. Rapeseed Barley Oats Molassed Hay Alkali- meal beet pulp treated straw Dry matter, % 87.1 89.0 88.8 87.8 86.2 78.5 % of DM Ash 8.0 2.8 3.1 9.4 6.6 10.1 Crude protein 40.2 12.9 13.7 13.3 8.5 4.5 Crude fat 2.2 2.4 6.2 0.5 2.0 0.8 Crude fibre 13.3 5.4 11.2 15.8 35.7 44.6 N-free extract 36.3 76.5 65.8 61.0 47.2 40.0 kg/f.u. 1.25 0.97 1.10 1.19 2.60 2.17 DCP, g/f.u. 363 83 104 91 92 20 culating the net energy value (fattening feed unit) was 63 (Anon. 1969). recommended (Syrjälä-Qvist et ai. 1982) the palatability of the concentrate mixture was good. The daily amount of rapeseed meal consumed by the animals was 1.2 kg and this supplied about 58 % of their digest- ible crude protein. Results and discussion Feed intake and growth rate In the UREA group, the mean consump- tion of rapeseed meal was 400 g per animal and day and that of urea 84 g/day, the maxi- mal amounts of urea being 40 g/100 live weight kg. In this group the bulls received about 38 % of their digestible crude protein from urea and 20 % from rapeseed meal. The palatability of the concentrate mixture was good in this group also. The alkali treatment improved the feeding value of the straw. The amount needed for a feed unit was about 2.2 kg, or less than for hay (Table 2). The amount of untreated straw generally needed for a feed unit is 5.5—6.0 kg (Anon. 1969). On average the bulls consumed 2.3 kg (variation I.B— kg) straw per day, or 0.77 kg DM/100 kg live weight. The contribution of straw to the total DM intake in the UREA and RSM groups was 34 and 33 °7o, respectively. The intake of treated straw varied widely between the animals. Similar intakes of alkali-treated straw have been obtained in other experi- ments with growing bulls (Arnason 1980). In the RSM group the roughage/concen- trate ratio, calculated from the dry matter, Table 3. Live weight gain, feed consumption and slaughter results. Groups RSM UREA After 6 months of age, the treated straw was the only roughage given to thebulls. The daily intake of straw was then 4.3 kg/ animal. Between the age of 3 and 6 months they also consumed hay, the average daily amount being 840 g/animal. Initial live weight, kg Final live weight, kg Live weight gain, g/day DM supply, kg/day Energy supply, f.u./day DCP supply, g/day 140 141 347 356 1072 1111 5.4 5.5 4.4 4.5 583 582 DCP, g/f.u. 132 134 In the RSM group, the concentrate mix- ture contained 32 % rapeseed meal (Table 1). Although this proportion of rapeseed meal was about twice as high as is generally Feed conversion rate, f.u./kg gain 4.16 169 4.08 176Carcass weight, kg Dressing, % 48.9 49.4 139 was 39/61 and in the UREA group it was to 181 kg. The dressing %in both groups 40/60. This can regarded as reaching the optimal level (McCullough 1969). The live weight gain was even and similar in the two groups; it was somewhat higher in the UREA group, but the difference was not significant (P > 0.05) (Fig. 1, Table 3). The feed conversion rate was also similar in the two groups, or on average 4.1 f.u./kg live weight gain. Slaughter results and the health of the animals By the age of 10 months all the animals had reached a carcass weight of at least 160 kg. In the RSM group it varied from 161 to 183 kg and in the UREA group from 163 averaged 49 %. After slaughter, irritation of the mucous membrane of the small intestine was noted in all the animals; one animal had a liver abscess and there were three cases of inflam- mation of the kidneys. It has been reported from Norway that bulls fed on 4.7 kg DM ( = 69 %of total DM) of dry alkali-treated straw had heavier kidneys than bulls fed on untreated straw. In addition, after 12 weeks of feeding treated straw diarrhoea occurred and growth was retarded (Arnason 1980). According to our results, dry alkali-treated straw cannot be fed ad libitum as the only roughage for growing bulls. Acknowledgements. We wish to express our best thanks to Mr. Markku Nieminen for the technical as- sistance throughout the experiment. References Anon. 1969. Fodermiddeltable. Nord.Jordbr. forskeenes Fören. Gjovik, 40 p. Arnason. J. 1980. Torrlutet (NaOH) halm som för til slakteokser. Norges Landbrukshagskole. Institut for husdyrernähring. Melding Nr. 204. Daenicker, R. & Rohr.K. 1974. Rindermast. Land- und Haus-wirtschaftlicher Auswertungs und Informa- tionsdienst. Bonn-Bad Godesberg. Nr. 372, 19 p. McCullough, M. E. 1969. Optimum feeding of dairy animals. Univ. of Georgia Press, Athens. 180 p. Syrjälä-Qvist, L., Tuori, M. & Setälä, J. 1982. Rapeseed meal as a protein source for high-produc- tion dairy cows on grass silage- and hay-based feeding. J. Scient.Agric.Soc.Finl. 54: 145—153. Ms received April 12, 1984 140 SELOSTUS Rapsirouhe ja urea kasvavan lihanaudan valkuaisen lähteenä lipeäolkiruokinnalla Liisa Syrjälä-Qvist ja Mikko Tuori Helsingin yliopiston, kolieläinlieteen laitos, 00710 Helsinki 71 Koe tehtiin 12 mullilla ikävälillä 3 1/2—10 kk. Valku- aisen lähteenä oli toisessa ryhmässä Tower rapsirouhe ja toisessa urea + rapsirouhe. Rapsirouheen osuus edelli- sessä ryhmässä oli 32 % väkirehuseoksessa, joka sisälsi myös ohraa, kauraa ja melassileikettä. Rapsirouheen saantimäärät olivat keskimäärin 1.2 kg/ eläin/pv ja se korvasi noin 58 % eläimen saamasta sula- vasta raakavalkuaisesta. Ureaa sisältävässä ryhmässä ureaa oli 2 % väkirehuseoksessa ja keskimääräinen an- nostus 84 g/eläin/pv. Urea korvasi noin 38 % sulavasta raakavalkuaisesta. Rapsirouhetta eläimet saivat tässä ryhmässä keskimäärin 400 g/eläin/pv eli 20 % sulavasta raakavalkuaisesta. Väkirehuseoksen maittavuus oli mo- lemmissa ryhmissä hyvä. Lipeäolkea eläimet söivät keskimäärin 2.3 kg/pv eli 0.77 kg kuiva-ainetta/100 elopainokiloa. Eläinten välil- lä oli yksilöllisiä eroja oljen syönnissä. Heinää mullit saivat puolen vuoden ikään asti keskimäärin 840 g/ eläin/pv, mutta tämän jälkeen lipeäolki oli ainoana kar- kearehuna. Eläinten kasvu oli tasaista eikä ryhmien välillä ollut merkitseviä eroja, joskin ureaa saaneet eläimet kasvoi- vat hieman paremmin kuin rapsiryhmän eläimet, keski- määräisten päiväkasvujen ollessa vastaavasti 1111 g ja 1072 g sekä teuraspainojen 10 kk:n iässä 176 kg ja 169 kg. Rehua kului molemmissa ryhmissä keskimäärin 4.1 ry/lisäkasvukilo. Kaikilla eläimillä oli ohutsuolen limakalvo ärtynyt. Yhdellä eläimellä oli mätäpesäke maksassa ja kolmella munuaistulehdus. Tämä antaa aiheen epäillä lipeäoljen soveltuvuutta ainoaksi karkearehuksi. 141