Literature Review Feed, energy and protein intakes of horses A review of Finnish feeding trials Markku Saastamoinen Saastamoinen, M. T. 1993. Feed, energy and protein intakes ofhorses A review of Finnish feeding trials. Agric. Sci. Finl. 2: 25-32. (Agric. Res. Centre of Finland, Equine Res. Sta., FIN-32100 Ypäjä, Finland.) The aim of this study was to evaluate the feed, energy and protein intakes of horses engaged in different performances by reviewing results and data concerning feed consumption in 17 feeding trials with a total 356 horses, conducted between 1972 and 1992. The dry matter intake was found to average 1.6-1.8% ofbody weight for working horses and pregnant mares, and 2-3.5% for lactating mares. According to the results most of the exercising horses could be fed with energy and protein amounts currently recommended for moderate work. In Standardbred trotters, the average energy intake corresponded to the current requirements for light work. The individual variation in energy consumption among horses engaged in work of the same intensity was consid- erable, and seemed to be larger for Finnhorses than for warmblooded horses. The establishment of new nutrient requirements and feeding recommendations separately for trotters and riding horses of these two breeds, i.e. Finnhorses and warmblooded horses, seems justified. Key words: feed consumption, feeding standards, nutrient requirements, nutrition Introduction The Finnish feeding recommendations and nutrient requirements of horses are based mainly on old feeding standards for horses used in farm work (e.g. Poijärvi 1938). Attempts have also been made to adapt and apply recommendations used in some other countries. A number of recommendations have been published for Finnish horse owners and breeders (e.g. Aalto 1954, Salo et. al. 1990,Pel- tonen 1988, Saastamoinen 1989), as well as in- ternationally by Peltonen (1986) and Staun (1990). It may be that the current Finnish feeding recom- mendations misjudge the energy and protein needs of modem horses. Moreover, they ignore the differ- ences between breed and purpose of the horses (e.g. warmblooded horses vs. Finnhorses; trotter vs. saddle horse). These defects are most obvious in the case of adult exercising horses, since nutritional research in Finland has been focused mainly on brood mares and foals, while the nutrition of exer- cising horses has received only limited attention. Evaluation of nutrient allowances is needed to determine the actual nutrient requirements of horses. The aim of this study, therefore, was to review the feeding data and results of a number of Finnish feeding trials in order to assess the feed, energy and protein intakes of horses engaged in differentactivities. These estimates were then com- pared to the current feeding recommendations used in Finland and in some other countries. 25 Agric. Sci. Finl. 2 (1993) https://www.c-info.fi/en/info/?token=DD15teg59EWg0qkF.-sNdOy6a4Tujzdt2T4xflA.sNu172N6tgQjPTaTQaUkI0QUqFfuQIpU_o9jaArD0uH8_NBaivn6o2h15_-BLAHg8F_pqEThi-bVrfbTgm1oSDF4_INNJ7L_44Ep9mjLBRwfLmU4o31cVv1o7nXCdi3R_YJiitU2p7S__Prc38kj3t5NGLGCw8inHgumkvBevSscUn5x7g7a3BijK9sifl7v1_YvIbbTyxTQ0hwg2g1CNejICSncGgnp5-VeHWVgsBbXa9reXhOK_A5QLTpp4OobXgu4Th2PHCZAkOV5uQ Agric. Sci. Finl. 2 (1993) Table 1. List of reviewed feeding trials. Author No. of Breed, Mature Daily Basal horses use weight work diet kg hrs Kossila et al. (1972) 24 Wbrh 557 l-2„5 h-o Kossila & Ljung (1977) 22 Wbrh 525 1.85 h-o, h-op Peltonen et al. (1978) 16 Fh tr 525 1.5 ho, h-o-gp Kossila et al. (1979) 18 Fh pui 550 1.5 h-o, h-o-op Saastamoinen (1983) 14 Wbst 560 1 h-o Saastamoinen (unpubl.) 20 Fh rh, tr 530 1-1.5 h-o Saastamoinen (unpubl.) 20 Fh rh, tr 530 1-1.5 h-o Saastamoinen & Juusela (1993); Juusela (1989) 40 Wbrh;Fh 561; 1 h-o rh,tr 520,501 Saastamoinen & Hyyppä (unpubl.) 18 Wbtr; 445; 0.5-0.75 h-o-m Fhtr 525 Saastamoinen et al. (1992) 30 Wbrh; 573; Fhrh,tr 527,529 1.5 h-o, h-o-hp Peltonen et al. (1980) 12 Fh br. m. 530 h-o Peltonen (1986) 20 Fh br. m. 530 h-o Saastamoinen et al. (1990); Lähdekorpi(l99l) 25 Fh br. m. 530 h-o Kossila et al. (1978) 15 Fh wean. 530 h-o Peltonen et al. (1985) 20 Fh wean. 530 h-o Saastamoinen & Koskinen (1993) 22 Fh wean. 530 h-o Saastamoinen (unpubl.) 20 Fh wean. 530 h-o, h-cm Total 356 Wb=warmblooded; Fh=Finnhorse; rh=riding horse; tr=trotter; pul=load pulling; st=stallion in performance test; br.m.=brood mare; wean=weanling; h=hay; o=oats; op=oats pellets; gp=grass pellets; m=molasses; hp=hay pellets; cm= concentrate mixture The reviewed feeding trials The trials of which results and data on feed con- sumption were available are presented in Table 1. The trials were carried out between 1972and 1992. A total of356 horses were involved in thereviewed trials, representing different breeds and purposes. Only one of these trials (Kossila et al. 1972) had been conducted for the purpose of measuring the nutrient intake of the horses. The other trials had been made to compare various feeds, diets and nutrient levels, and the horses fed to maintain their body weight and visual body condition. The forage- to-grain ratios in the trials were about 1 to 0.5-0.6. Determination of energy and protein intakes Energy allowances were determined in terms of fattening feed units (FFU). Metabolizable energy (ME) values for feeds were also given in some trials, or if not, they were calculated from the di- gestible nutrients of the feed according to MAFF (1975). Digestible energy (DE) intakes were then converted from the ME intakes using the ME/DE ratio 0.900 (Reid and White 1978, Vermorel et al. 1984, Vermorel et al. 1991) to compare the energy intakes to German and American recom- mendations. Protein was measured as digestible 26 Literature Review Agric. Sei. Fin I. 2 (1993) Table 2. Literature averages for dry matter intake (kg) of horses (500 kg bwt) in different performances Warmblooded trotter 8.0 Finnhorse trotter 8.3 Warmblooded riding horse 8.8 Finnhorse riding horse 8.1 Finnhorse load pulling 8.8 Pregnant mare 8.0-8.5 Lactating mare 10.0- 18.8 crude protein (DCP). To obtain the energy intake required for work, the average maintenancerequirements of the horses were estimated as presented by Salo et al. (1990), Dlg (1984) and Nrc (1989). The difference be- tween Dlg (1984) and Nrc (1989), in this case, is that Dlg (1984) uses metabolic weight (weight 0 75 ) instead of body weight. All results in the present study are for a horse weighing 500 kg. Results and discussion Dry matter intake The variation in dry matter (DM) intake between horses in different uses was small (Table 2). The average DM intake of working horses in the re- viewed trials varied from 8.0 to 8.8kg per day. This is equivalent to 1.6-1.8% of the body weight and agrees with both DLG (1984) and NRC (1989). However, in Finland, this corresponds only to the recommendations for horses performing light (farm) work (Poijärvi 1938). For pregnant and lactating mares, the DM intake in the reviewed trials was 8.0 to 8.5 kg and 10.0 to 18.0 kg, respect- ively. Energy intake Work The average daily energy intake of a 500 kg Stand- ardbred trotter (n=9 horses) has been reported to be 5.5 FFU (80.9 MJ DE) (SAASTAMOINEN and Hyyppä, unpublished). The equivalent for Finnhorse trotters (n=so) can be calculated to be 6.1 FFU (89.7 MJ DE) (Peltonen et al. 1978, Saastamoinen et ai. 1992, Saastamoinen and Juusela 1993, Saastamoinen and Hyyppä, un- published, Saastamoinen, unpublished). In Standardbred trotters, the average daily ener- gy intake corresponds to the requirements of light work as given by Salo et al. (1990), Meyer (1992) and DLG (1984), but it was about 5% lower than that recommended for light work by NRC (1989). In Finnhorse trotters, the average daily energy inta- ke agrees with therequirements for moderate work given by Salo et al. (1990) and by German stand- ards, but it was about 10% below the NRC ( 1989) recommendations for moderate work. In the case of Finnhorses, however, the individual daily energy intake among horses in different studies was found to vary from 5.0 to 9.5 FFU (73-137 MJ DE), with the upper limit corresponding to the energy recom- mendations for intense work (SALO et al. 1990, DLG 1984, NRC 1989). It is not possible to draw any conclusions about Standardbred trotters becau- se of their small number included in the trials. A warmbloodedriding school horse (n= 16) wor- king 2 to 2.5 hours daily consumed 6.3 FFU (106.4 MJ DE) per day on an average (Kossila et al. 1972). The individual variation was about 4.8 to 8.0 FFU (81-135 MJ DE). A riding horse (n=6) that was intensively ridden (“privately owned”) one hour per day required 6.2 FFU (104.9 MJ DE), on an average (Kossila et al. 1972). In the studies of Kossila and Ljung (1977) (n=22), and Juusela (1989) (n=l6), the average energy consumption of warmbloodedriding horses in regular work (education of riding instructors or light competition) was 5.7 (91.6 MJ DE) and 6.4 FFU (88.6 MJ DE) per day, respectively. The indi- vidual variation among the horses in the data of Juusela(1989) was about6.0-8.0 FFU (83-111 MJ DE). The energy intake of riding horses of the Finn- horse breed (n=4l) in regular work (riding teaching in groom training programme and light competi- tion) can be estimated to average 5.7FFU (88.1 MJ DE) per day on the basis of different studies (SAAS- TAMOINEN et al. 1992, Saastamoinen and 27 Literature Review Juusela 1993, Saastamoinen, unpublished). This corresponds to the energy requirements of warmblooded riding horses in regular work. The individual variation between horses in different tri- als was 4.5-9.5 FFU (67-137 MJ DE). The average daily energy intake of young stal- lions during a 100-day test was 5.6 FFU (Saas- tamoinen 1983). Work-horses of the Finnhorse breed pulling light loads consumed5.4 FFU per day on an average (Kossila et al. 1979). The energyexpenditure for work increased along with increased work intensity, as illustrated in Fig- ure 1, for which the data were adapted from Juusela (1989). It depended also on the use of the horse (Table 3). For one hour of work (100 kg' 1 ), an intensively ridden “privately owned” horse required more than two times the energy consumed by riding school horses and other regularly exercised horses (Table 3). Similarly, the energy required by intensi- vely ridden horses for one hour of work was about twice that consumed by young stallions during their 100-day performance test (SAASTAMOINEN 1983). The energy consumption for one hour of work by Finnhorse riding horses was about 25% lower than the energy required by Finnhorse trotters. The energy consumption (above maintenance) calculated per one hour of work and 100 kg body weight for different horse groups by type of work were in reasonable agreement with the energy ex- penditures reported for medium trot by DLG (1984) and for fast walk - slow trot by Hintz et al. (1971) and Paganand Hintz (1986), as well as for light to moderate work (riding horses) by Martinßosset (1990). Kossila et al. (1972) reported a higher energy consumption for work by geldings than by mares. Also in the data ofSaastamoinen et al. (1992), the energy intake of Finnhorse stallions and geldings was somewhat higher than that of mares. It can be assumed that most horses can be fed according to the current recommendations for mod- erate work. However, there was considerable indi- vidual variation in energy consumption among hor- ses engaged in work of the same intensity. The variation was wider in Finnhorses than in warm- blooded horses. Pregnancy and lactation The average daily energy intake of pregnant mares (n=43) (late pregnancy; 9-11 months ofpregnancy) varied from 4.5 to 5.8 FFU in different studies (Peltonen et al. 1980, Peltonen 1986, Saas- tamoinen et ai. 1990, Lähdekorpi 1991). The average daily consumption of 5.8 FFU (94.3 MJ DE) reported by Lähdekorpi (1991) was above that recommended by DLG (1984) and NRC (1989). The individual variation among horses in that trial was 5.2 to 7.1 FFU (79-108 MJ DE). Peltonen et al. (1980) reported an average en- ergy intake of 6.9 FFU (123.7 MJ DE) per day (n=l2) during early lactation (1-2 months p.p). Saastamoinen et al. (1990) measured a somewhat higher average daily energy intake, i.e. 7.6 FFU (142.9 MJ DE), during the first three months of lactation (n=2s). DLG (1984) recommends 120- 127 MJ DE and NRC (1989) 118 MJ DE for delat- ing mares during early lactation. Growth The average energy requirement of weanling foals (mature weight appr. 530 kg), 6 to 12months of age (n=62), varied from 3.5 to 5.0 FFU (65-75 MJ DE) per day in different trials (PELTONEN et al. 1985, Saastamoinen and Koskinen 1993, Fig. 1. The energy consumption (FFU/d) of horses (500 kg bwt) for work during the winter feeding period. Work inten- sity, but not amount, increased during the period. Wam- blooded riding horses were ridden in a heated and Finnhorse riding horses in an unheated riding hall. Finnhorse trotters were trained outdoors (data adapted from Juusela, 1989). 28 Literature ReviewAgric. Sei. Finl. 2 (1993) Table 3. Collection of daily energy intakes (FFU and MJ DE) above that of maintenance for mature horses (500 kg bwt) in different work (literature averages). Maintenance Per requirements day h ' and 100 kg" 1 calculated according to Warmblooded trotter 1.0 0.18 - 0.36 FFU DLG(I9B4) 17.5 3.2 - 6.4 MJ DE NRC(I9B9) 12.3 3.1-4.6MJDE Finnhorse trotter 1.6 0.22 -0.32 FFU DLG(I9B4) 26.3 3.5 - 5.3 MJ DE NRC(I9B9) 21.1 2.9-4.6MJDE Warmblooded riding school horse 1.8 0.14 - 0.18 FFU DLG (1984) 43.0 3.4 - 4.3 MJ DE NRC(I9B9) 37.8 3.0-3.BMJDE Warmblooded riding horse (education, competition) 1.6 DLG (1984) 26.7 3.1 - 5.4 MJ DE NRC(I9B9) 21.5 2.5-4.1 MI DE Warmblooded riding horse (intense riding 1 h) 1.7 0.34 FFU DLG (1984) 41.5 8.3 MJ DE NRC(I9B9) 36.5 5.1 MJ DE Warmblooded stallion during perf. test 1.1 0.2 FFU Finnhorse riding horse 1.2 0.16-0.24 FFU DLG (1984) 24.7 3.3-4.9MJDE NRC (1989) 19.5 2.6 - 3.9 MJ DE Finnhorse load pulling 0.9 0.18 FFU Saastamoinen, unpublished). This agrees with NRC (1989) and Martinßosset (1990) but is somewhat higher than that recommended by DLG (1984). Kossila et al. (1978) measured an average daily intake as high as 6.9 FFU (82.1 MJ DE) (n=ls) for weanling Finnhorse foals, which was much above the recommended energy intake for weanlings inFinland (e.g. Aalto 1954,Salo et al. 1990). Protein Work The average digestible crude protein (DCP) allow- ance for working horses (trotters and riding horses) in the different studies was 580 g per day (Kossila et al. 1972,Peltonen et al. 1978,Saastamoinen et al. 1992, Saastamoinen and Juusela 1993, Saastamoinen and Hyyppä, unpublished Saas- tamoinen, unpublished). This was about 100 g more than that recommended by Dlg (1984). How- ever, Zmua (1991) reported for German Stand- ardbred trotters a DCP intake of 180% of the level recommended by DLG (1984). The DCP intake per FFU varied from about 90 to 116 g/FFU (Table 4), and was not found to differ significantly between horses in differentperformances. Pregnancy and lactation The average DCP intakes reported for pregnant mares during late pregnancy (9th-11th month) were 550-670 g per day, and 94-105 g/FFU (Peltonen 1986,Saastamoinen et al. 1990).Saastamoinen et al. (1990) reported a DCP intake of 900 g (118 g/FFU) per day during early lactation (1-3 months 29 Agric. Sci. Finl. 2 (1993)Literature Review Table 4. Literature averages for protein intakes (DCP g/FFU) of horses in different performances. Warmblooded trotter Finnhorse trotter 94 95 Warmblooded riding horse Finnhorse riding horse 90-116 98 94-105 120-140 110- 150 Pregnant mare Lactating mare Weanling foal p.p.) and Peltonen et al. (1980) reported an avera- ge daily intake of 957 g DCP. Peltonen (1986) suggested a minimum requirement of 700-900 g DCP per day during early lactation. The reported protein intakes were higher than the recommended levels in Germany (DUG 1984) for pregnancy, but somewhat lower than those for lactation. Growth The digestible crude protein intakes of foals (6-12 months) in different trials (Kossila et al. 1978, Peltonen et al. 1985, Saastamoinen and Koski- nen 1993, Saastamoinen, unpublished) varied from 370 to 1081 g (110-150 g/FFU) per day. How- ever, it seems that an intake of 480-550 g DCP per day is adequate for normal growth of weanling foals, which agrees with DUG (1984), and that the lysine content of the diet is more important than the total protein intake (Saastamoinen and Koski- nen 1993, Saastamoinen, unpublished). General discussion It appears that the energy and protein recommenda- tions for adult working horses in Finland today are overestimated. This is because the old feeding re- commendations, originally made for horses in farm work, are still in use. Furthermore, the individual needs of a single horse and differences between breeds and purposes of the horses are not well recognized by the horse owners. It is particularly important to pay attention to the requirements of high performance horses. IGNA- toff and Hintz (1980) and Gallagher et al. (1992) in USA, and Zmua (1991) in Germany, reported much higher DE and protein intakes for Standardbred trotters onrace tracks than the intakes reported in the studies reviewed here. However, big differences between stables and individual horses were observed also in the U.S. and German studies. The horses included in the reviewed trials were not on a very high performance level. Riding horses were used mainly in education or they were trained for low-level competitions (e.g. dressage in ele- mentary classes: 100-110 cm obstacles). The trot- ters were trained mainly according to a special schedule which included slow trotting daily plus a weekly "heat" (interval) of 1000 to 2000 m at a speed of 1 min. 27 sec. to 1 min. 24 sec. per kilo- metre for Standardbred trotters, and 1 min. 40 sec. to 2.00 min. per kilometre for Finnhorse trotters. However, performance depends more on the ge- netic potential of the horse than on its nutrition. Horses with different potentials are mainly trained with the same methods, so it can be assumed that no major differences in the feed and nutrient intakes should be expected between horses on different performance levels. Different training schedules and other environmental factors may be the reason for the considerable differences between the re- viewed Finnish studies and the studies carried out on race tracks in USA and Germany. It can be concluded that new norms for nutrient requirements and feeding standards are needed in Finland separately for trotters and riding horses of both breeds (Finnhorses, warmblooded horses). In addition, riding horses should be divided into dif- ferent categories, e.g. riding school horses, compe- tition horses and pleasure horses. Concerning pregnant and lactating mares, the energy and protein recommendations given by PEL- TONEN et al. (1980) and Peltonen (1986) and Salo et al. (1990) are still relevant and correspond to foreign recommendations. As regards growing horses, recommendations both for outdoor housing and for traditional indoor housing are needed, because of the influence of temperature on feed consumption (Cymbaluk and Christison 1990). It seems that the current Finnish protein recommendations (in terms of digestible 30 Literature ReviewAgric. Sei. Finl. 2(1993) crude protein) for growing foals could be decreased by about 10-15% if the lysine intake is as high as recommended by e.g. NRC (1989). The net energy system, on which the FFU and also the French horse feed unit (UFC) are based, is the best basis for comparison of the energy values of feedstuffs and can be considered the most suit- able system in horse nutrition (e.g. Martin-Ros- SET 1992), whereas the digestible energy (DE) sys- tem, overestimates the energy values of feeds. The maintenance FFU requirement (Salo et al. 1990) calculated per kilogram of metabolic weight equals the French horse feed unit (UFC) requirement for maintenance. The energy requirements of exercising horses seem to be more efficiently determined per one hour of work than per day, because there is more variation in the amount of daily activity and work than, e.g., in the training methods and training in- tensity in a particular horse group. However, it is complicated to determine the energy requirements for work because there are so many factors affect- ing these requirements. In addition to work intens- ity, factors such as terrain, type ofground surface, and ability of the rider affect the energy expenditure of a horse. Feeds and their combination in the diet, as well as the breed and sex of the horse, also may have an influence on energy consumption. Further- more, climatic conditions, especially temperature and wind velocity, have been found to affect the energy consumption of a horse (PAGAN and HINTZ 1986, CYMBALUK and CHRISTISON 1990). Thus, more research is needed before new recommenda- tions can be established. It is also important to utilize all available data from practical conditions in determining the recommendations. References Aalto, O. 1954. On feeding of foals. (In Finnish English summary). Maatalous ja koetoiminta VIII. 8 p. Cymbaluk, N.F. & Christison. G.I. 1990. Environmental effects on thermoregulation and nutrition of horses. In: Hintz, H.F. (ed.). The veterinary clinics of North Amer- ica. Equine Practice. Clinical nutrition, vol 6,2: 355-372. DLG 1984. DLG-Futterwerttabellen fur Pferde. 2. Auflage. DLG-Verlag, Frankfurt am Main. 122 p. Gallagher, K., Leech, J. & Stowe, H. 1992. Protein, energy and dry matter consumption by racing standardbreds: A field survey. J. Equine Vet. Sci. 12: 382-388. Hintz, H. F., Roberts, S. J., Sabin, S. W. & Schryver, H. F. 1971. Energy requirements of light horses for various activities. J. Anim. Sci. 32: 100-102. Ignatoff, J. & Hintz, H. F. 1980. A survey of feeding prac- tices at two Standardbred racetracks. Feedstuff 52: 24-25. Juusela, J. 1989. Vitamiinitäydennykset hevosten ruokin- nassa. (M. Sci. Thesis.) 76 p. Kossila, V., Heikkilä, T. & Tupamäki, A. 1979. Whole oat plant pellets as a sole source of diet for horses. Paper. 30. Ann. Meet, of Eur. Assoc, for Anim. Prod. —, Lillkvist, A., Virtanen, E„ Tanhuanpää,E. & Rauvala, L. 1978. Blood and hair composition of Finnfoals. Paper. 29. Ann. Meet of Eur. Assoc, for Anim, Prod. & Ljung, G. 1977. Value of whole plant pellets in horse feeding. Ann. Agric. Fenn. 15: 316-321. —, Virtanen, E & Maukonen, J. 1972. Hay-oat diet as a source of energy, digestible crude protein, minerals and trace elements for saddle horses. (In Finnish English abstract), J. Sci. Agr. Soc. Finl. 44: 217-227. Lähdekorpi, M. 1991. Ruokinnan kupari- ja sinkkitason vaikutus varsan kasvuun ja luuston kehitykseen. (M. Sci. Thesis.) 95 p. MAFF 1975. Energy allowances and feeding systems for ruminants. Ministry of Agriculture, Fisheries and Food. Technical Bulletin 33. London. 9 p. Martin-Rosset,W. (ed.). 1990.L’alimentationdeschevaux. Techniques et pratiques. INRA. Paris. 232 p. 1992. Nutrient requirements and allowances for energy and protein in horses. Paper. 43. Ann. Meet, of Eur. Assoc, for Anim. Prod. Meyer, H. 1992. Pferdefiitterung. 2. Auflage. Paul Parey, Berlin und Hamburg. 223 p. NRC 1989. Nutrient requirements of horses. National Acad- emy Press, Washington D.C. 100 p. Pagan, J. D. & Hintz, H. F. 1986, Equine energetics. 11. Energy expenditure in horses during submaximal exer- cise. J. Anim. Sci. 63; 822-830. Peltonen, T. 1986. Nitrogen level and allowances in pregnancy and lactation. Paper, 37th Ann. Meet, of Eur. Assoc, for Anim. Prod. 1988. Hevosen ruokinta. In: Hevostalouden laskelmia. Suomen Hippos, Helsinki, p. 3-21. —, Alitalo, 1., Koskinen, E. & Juoa. J. 1985. Varsojen kasvukoe. Mimeogr. Maataloustieteen päivät 1985, Hel- sinki. —, Kossila. V., Antila, V. & Huida, L. 1980. Effect of protein supplement on milk composition of mares and growth rate of their foals. Paper. 31. Ann. Meet, of Eur. Assoc, for Anim. Prod. —, Kossila, V., Syrjälä, L. & Immonen I, 1978. Feeding value of grass molasses pellets and their influence on the faecal microbiota of horses. Ann. Agric. Fenn.l7:lo9- 114. 31 Agric. Sci. Finl. 2 (1993)Literature Review Poijärvi, I. 1938. Tuloksia hevosten ruokintakokeista. Val- tion maatalouskoetoiminnan tiedonantoja No. 154. 27 p. Reid, J. T. & White, O. D. 1978. Comparative energetic efficiency of farm animals. Univ. of. Arkansas Agr. Exp. Sta. Special Rep. 72. Saastamoinen, M. 1983. Stallion performance test in 1983. (In Finnish). Jäsenlehti 3/83: 7-8, Ratsujalostusliitto. 1989. Feeding ofriding horses. (In Finnish). In: Hevos- muistio. Ratsastuskustannus Oy, Helsinki, p. 95-97. & Juusela, J. 1993. Serum vitamin E concentration of horses on different vitamin E supplementation levels. Acta Agric. Scand., Sect. A, Animal Sci. 43:52-57. & Koskinen, E. 1993. Influence of quality of dietary protein supplement and anabolic steroids on muscular and skeletal growth of foals. Anim. Prod. 56:135-144 —, Lähdekorpi, M. & Hyyppä. S. 1990. Copper and zinc levels in the diet of pregnant and lactating mares. Paper. 41st Ann. Meet, of Eur. Assoc, for Anim. Prod. —, Manninen, M. & Rantanen, A. 1992. Compounded pel- leted fibre feed and hay pellets as substitutes for hay in horse feeding. Agric. Sei. Eini. 1: 225-232. Salo, M.-L., Tuori. M. & Kiiskinen, T. 1990. Rehutaulukot jaruokintanormit. Helsinki. 70 p. Staun, H. 1990. Energy and nitrogen systems used in north- ern Europe for estimating and expressing value of feed- stuffs in horse. Paper. 41st Ann. Meet, of Eur, Assoc, for Anim. Prod. Vermorel, M., Jarrioe. R. & Martinßosset, W. 1984. Me- tabolisme et besoins energetiques du cheval, le systeme des UFC. In: Le Cheval, Reproduction, Selection, Ali- mentation, Exploitation. I.N.R.A. Paris, p. 239-276. —, Martin-Rosset, W. & Vernet, J. 1991. Energy utiliza- tion of two diets for maintenance by horses; agreement with the new French net energy system. J. Vet. Sci. 11: 33-35. Zmija, G. 1991. Futterungspraxis bei Galopp- und Tra- brennpferden. Thesis. Tierärztliche Hochschule Han- nover. 79 p. Manuscript received December 1992 Markku Saastamoinen Agricultural Research Centre of Finland EquineResearch Station FIN-32100 Ypäjä, Finland SELOSTUS Hevosen rehun syönti sekä energian ja valkuaisen saanti arvioituna suomalaisten ruokintakoetulosten perusteella Markku Saastamoinen Maatalouden tutkimuskeskus Hevosen rehun, energian ja valkuaisen saanti arvioitiin 17 suomalaisen ruokintakokeen tulosten jarehunkulutustietojen perusteella. Kokeet oli tehty vuosien 1972 ja 1992 välisenä aikana, ja niissä oli ollut mukana yhteensä 356 eri ikäistä ja erilaisessa käytössä ollutta hevosta. Urheiluhevoset jakanta- vat tammat söivät rehun kuiva-ainetta keskimäärin 1,6-1,8 % elopainostaan. Imettävien tammojen kuiva-aineen syönti oli keskimäärin 2-3,5 % niiden elopainosta. Samanlaisessa rasi- tuksessa olevien hevosten energiankulutuksessa esiintyi suur- tayksilöllistä vaihtelua. Vaihtelu oli suurempaa suomenhevo- silla kuin lämminverisillä. Tulosten mukaan suurin osaaikui- sista urheiluhevosista voidaan ruokkia nykyisten keskiras- kaan työn normien mukaisesti, mutta uudet ruokintasuosituk- set erikseen ratsu- jaravihevosille ovat tarpeen. Suosituksissa on otettava huomioon myös rotujen väliset erot. 32 Literature ReviewAgric. Sei. Finl. 2 (1993)