High Feeding Level Research Articles

The effects of levels of concentrate offered and inclusion of maize gluten or fish meal in the concentrate on reproductive performance and blood parameters of dairy cows

ABSTRACTFive randomized-block experiments were carried out over 2 years using British Friesian cows managed as three separate herds. The effects of offering cows different levels of concentrates, ranging from 0·8 to 7·2 kg/day, in addition to grass silagead libitumduring the winter period on reproductive performance was investigated. The effects of substituting 4 kg/day maize gluten, or 0·8 kg/day fish meal, for part or all of the standard concentrate were also examined.Neither level of concentrates nor the inclusion of maize-gluten meal significantly affected reproductive performance even where milk production and quality was considerably influenced. The inclusion of fish meal improved conception rates to all services (0·64v.0·44;P< 0·05) and reduced the number of services required per conception (1·62v.2·31;P< 0·01).Plasma urea levels were raised consistently by the feeding of fish meal and, with the exception of weeks 2 and 6 of lactation, by the feeding of higher levels of concentrates. From the 6th week of lactation levels of beta-hydroxybutyrate (BHB) in the blood were significantly higher in the group of cows receiving the highest level of concentrates. The BHB level at week 6 was correlated with the number of services required per conception.A number of relationships between production factors and fertility are also presented.

Nitrogen utilization and digestibility of amino acids by lambs fed a high-concentrate diet with limestone or magnesium oxide.

Effects were evaluated of high dietary levels of magnesium oxide (MgO) or limestone on DM, OM and CP digestibility, N balance and intestinal absorption of amino acids by lambs fed a high concentrate diet. Twelve wether lambs equipped with abomasal and ileal cannulas were blocked by weight and breeding and allotted to treatments in a randomized block design in two consecutive trials. Diets were control (800 g), control plus 1.5% MgO (812 g), control plus 1.5% limestone (812 g) and control plus 3.0% limestone (824 g) fed in two equal portions at 12-h intervals. Ruminal fluid pH differences were small. The pH of ileal digesta was greater (P less than .05) with MgO than with limestone (8.23 vs 7.73). Fecal pH was higher (P less than .01) for lambs fed all mineral treatments (avg 8.75) than for lambs fed the control (7.61) and was higher (P less than .01) when MgO (9.53) rather than limestone (8.36) was fed. Ruminal NH3N was lower (P less than .01) when lambs were fed MgO (11.9 mg/dl) compared with limestone (avg 31.2 mg/dl). Preintestinal DM digestibility was greatest (P less than .10) with limestone (avg 49.5%) feeding compared with feeding MgO (31.2%) or the control (35.4%). About 41.5% more essential (P less than .05) and 48% more nonessential (P less than .03) amino acids reached the small intestine when MgO was fed than when limestone was fed. Partial digestibility of amino acids in the small intestine was reduced (P less than .03) an average of 5 percentage units when MgO or limestone was fed. Feeding high levels of MgO or limestone to lambs did not improve the overall digestibility of DM, OM or CP. In fact, feeding high levels of MgO or limestone appeared to be detrimental, reducing intestinal absorption of amino acids.

Effects of source and level of copper on performance and liver copper stores in weanling pigs.

Five 28- to 33-d experiments involving 460 crossbred pigs weaned at 28 +/- 2 d of age (initial weight, 6.7 to 8.1 kg) were conducted to determine the effects of feeding high dietary levels of Cu sulfate (CuSO4) or Cu oxide (CuO) on rate and efficiency of gain and liver Cu stores of weanling pigs. The pigs were housed in groups of five to six/pen and fed a fortified, unmedicated, corn-soybean meal-dried whey basal diet (1.1% lysine, 30 ppm Cu). In Exp. 1 and 2, pigs (eight replicates) were fed the basal or the basal plus 125 or 250 ppm Cu from CuSO4 or CuO for 28 d. In Exp. 3 and 4, four replications were fed the same diets as in Exp. 1 and 2 plus two additional diets (500 ppm Cu from CuSO4 or CuO). In Exp. 5, dietary levels of 0, 125, 250, 375 or 500 ppm Cu from CuSO4 were evaluated using four replications. At the end of each experiment, the liver from one pig in each pen was collected for Cu analysis. Overall, rate and efficiency of gain were improved (P less than .01) by feeding 125 or 250 ppm Cu as CuSO4, with the 125 ppm dietary level being about 75% as effective in stimulating growth as 250 ppm. Performance of pigs was not different from controls when the highest (500 ppm) level of Cu (from CuSO4) was fed. Liver Cu increased 10- to 70-fold when 250 to 550 ppm Cu from CuSO4 was included in the feed.(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological effects of feeding high levels of magnesium to sheep.

The effects of feeding high levels of Mg to sheep on animal health, nutrient digestibility, metabolism of macro-minerals, blood and tissue mineral concentrations and hematological and histological tissue changes were evaluated. Six lambs were allotted to each of four diets supplemented with MgO to attain .2, .6, 1.2 or 2.4% Mg. Total fecal and urinary collections were made for the initial 20 d and last 10 d of a 50 d study. Diarrhea was noted in lambs fed the two highest Mg levels. Apparent digestibility of DM, ADF and CP decreased linearly (P less than .01) with increasing Mg levels. Dietary Mg levels did not affect (P greater than .05) rectal temperature, respiration rate or pulse rate. Apparent absorption and retention of Mg (g/d) were lowest in lambs fed 2.4% Mg until 15 d on trial, after which values increased linearly (P less than .01) with dietary Mg. Phosphorus absorption and retention decreased linearly (P less than .01) with increasing Mg levels. Increasing dietary Mg resulted in a linear increase (P less than .01) in serum Mg and variable increases (P less than .05) in erythrocyte Mg. Serum Ca was decreased linearly (P less than .05) and quadratically (P less than .05) by added Mg during the d 1 to 30 and 40 to 50 periods, respectively. Serum inorganic P was elevated consistently in lambs fed 2.4% Mg. A linear response to increasing dietary Mg (P less than .05) occurred in the Mg content of liver, kidney, rib bone and femur bone. Dietary Mg did not alter (P greater than .05) other criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of sodium phytate on growth and tissue mineralization of Penaeus japonicus and Penaeus vannamei juveniles

Feeding experiments were conducted to determine the effect of sodium phytate as a phosphorus source for Penaeus japonicus and Penaeus vannamei juveniles. The dietary value of this compound was compared with that of disodium phosphate in terms of survival rate, feed intake, growth rate, number of molts as well as the calcium and phosphorus content of different tissues. Diets used were semi-purified, with casein as the main protein source, and contained variable levels of sodium phytate or disodium phosphate. No significant differences were observed between the phosphorus sources tested, either in growth rate or in survival rate in P. japonicus. In contrast, the growth rate of P. vannamei was strongly depressed by the presence of phytic phosphorus. Feed intake and feed conversion were markedly increased in both species when sodium phytate was added. Analysis of the mineral content of the exoskeleton, muscle and hepatopancreas revealed no clear detrimental effect of phytic acid on mineralization. However, there was a slight tendency for phytate to diminish the ash content of tissues and to increase the calcium content of the ash. These data show that sodium phytate, even at high feeding levels, does not decrease calcium deposition, contrary to what is known in vertebrates.

Protein sources for monogastric and ruminant livestock in the cauca valley of colombia

Almost all attempts to improve animal production systems in developing countries have failed because they relied on the transfer of technologies from developed countries. Livestock production systems in industrialized conuntries have high rates of animal productivity, which at the same time require high quality feeds, rich in energy and protein. Most developed countries are located in temperate climates in which cereals and high quality feeds and grains can be readily grown and have the currency to provide all the fossil fuel inputs required.In order for Third World countries, located mostly in tropical regions, to adapt these systems, they must import exotic livestock and provide the high level of feeding at high cost. The transferred system has led to a loss of interest in indigenous breeds and local resources.It is clear that there is a great need for new rural development strategies that should take into account not only food production but also renewable energy resources, employment generation, self reliance and protection of the enviroment. This strategy includes selection of crops and cropping systems which maximize biomass production, nitrogen fixation and minimize the use of imported or expensive inputs.

Effects of air temperature, air velocity and feeding level on apparent digestibility, water intake, water loss and growth in calves given a milk substitute diet

ABSTRACTSix groups of eight 2-day-old calves were placed successively in a controlled environment chamber. Three groups were exposed to air temperatures of 10° and 25°C. A liquid diet of skimmed-milk substitute and 4 I/day of drinking (free) water was offered to each calf. Within each group, calves were allocated to either a low (<0·2 m/s) or a high (>3 m/s) air velocity and to either a low (30 g dry matter (DM) per kg M0·75per day) or a high (40 g DM per kg M0·75per day) feeding level. At 8 days of age the apparent digestibilities of DM at air temperatures of 10° and 25°C were 0·77 (s.e. 0·126) and 0·82 (s.e. 0·126) respectively (P > 0·05). The apparent digestibilities of DM were greater at the low feeding level with low air velocity than for either this feeding level with high air velocity or the high feeding level at both air velocities (P< 0·05) between which there was no significant difference (P > 0·05). At 8 days of age there were significant air temperature × air velocity (P< 001) and air velocity × feeding level interactions in the intake of free water (P< 005). There was a significant air temperature × feeding level interaction for total water intake (P< 0·05). Urinary water loss relative to total water intake was significantly greater at the low air velocity than at the high air velocity (P< 0·05).In a further two groups of eight calves given 30 g DM per kg M 75 per day at 8 days of age, the apparent digestibilities of DM at air temperatures of 10° and 25°C were 0·71 (s.e. 0·020) and 0·90 (s.e. 0·013) respectively (P< 0·01). In the same calves given 40 g DM per kg M0·75per day at 20 days of age, the apparent digestibilities of DM at air temperatures of 10° and 25°C were 0·89 (s.e. 0·009) and 0·93 (s.e. 0·011) respectively (P< 0·05). The free and total water intakes, the ratios of (total water intake-faecal water loss): total water intake and the urinary losses of water were significantly greater at the air temperature of 25°C than at 10°C (P< 0·05). Live-weight gains were lower at 10°C than at 25°C (P< 0·01).The results suggested that air temperature, air velocity and feeding level can affect the health and growth of calves less than 4 weeks of age.

Compensatory growth in cattle grazing different vegetation types

ABSTRACTFifty-four Charolais-cross weaned suckled calves were used in an experiment to investigate the effects of feeding level during the post-weaning winter on their subsequent performance, when grazing different vegetation types in summer. During winter they were given grass silage and barley at one of three levels (low, medium and high). The winter live-weight gains were 0·50, 0·75 and 0·96 (s.e. 0·019) kg/day (P < 0·001) for the low, medium and high treatments respectively. During summer they grazed either a sown ryegrass pasture (S), a hill reseed (R) or part of an unimproved hill (H).Live-weight gain during summer was inversely related to winter feeding level on all grazing treatments, the mean live-weight gains being 1·01, 0·79 and 0·65 (s.e. 0·027) kg/day (P < 0·001) for the low, medium and high winter feeding levels respectively. Summer treatment significantly affected performance, the live-weight gains being 0·88, 0·94 and 0·61 (s.e. 0·027) kg/day for the S, R and H treatments respectively. There was no interaction between winter and summer feeding treatment on live-weight gain. The organic matter intake was highest on the H treatment but the digestibility of herbage consumed was the lowest, resulting in the lowest digestible organic matter intake.Similar and high levels of performance were obtained on sown ryegrass pastures and reseeded hill land, while unimproved hill vegetation supported only moderate levels of live-weight gain. Compensatory growth occurred when a wide range of vegetation types were grazed in summer.

The relation between daily rings, body growth and environmental factors in plaice, Pleuronectes platessa L., juvenile otoliths

The deposition rate of sagittal otolith rings in post‐metamorphosed plaice, Pleuronectes platessa, was considered in relation to body growth under three feeding levels and two photoperiod regimes. Feeding levels and photoperiods significantly influenced the number of rings; more rings were deposited at higher levels of feeding and in longer photoperiod regimes. There was also a linear relationship between fish growth and the number of rings. The results suggest that sagittal rings could be used for aging wild juvenile plaice during the period of the growing season when growth rate is greater than 0.1 mm day1.

The effect of feed intake during late pregnancy on the performance of sows when fed a common high level during lactation

It is established that backfat depth and body condition during late pregnancy and lactation can be manipulated through changes in feed intake (Harker and Cole, 1984). Other work has shown that high level feeding throughout pregnancy is associated with a reduction in voluntary feed intake (e.g. Salmon-Legagneur and Rerat, 1962; Harker and Cole, 1985). However, it remains unclear whether high level feeding during late pregnancy alone has any effect on subseguent voluntary feed intake or changes in liveweight and backfat depth during lactation.The present experiment was designed to compare the performance and body condition changes of sows fed different levels in late pregnancy followed by a common and relatively high feed level during lactation.

Effects of Feeding Level, Slaughter Age and Implantation on Growth and Carcass Composition of Holstein and Friesian Steers

In order to increase milk production per cow, Friesian cows are being bred to Holstein bulls. As yet, there are few pure-bred Holsteins in commercial production in Ireland but there are increasing numbers of Holstein x Friesian and Holstein x (Holstein x Friesian) calves available for beef production. The main difference between Holstein and Friesian steers is that the former have poorer carcass conformation. The use of anabolic agents and an increase in slaughter weight might improve carcass conformation. The objectives of the present experiment were (1) to compare the growth and carcass composition of 3/4 Holstein and Friesian steers, (2) to measure the effects of implantation with anabolic agents in both these breed types, (3) to determine the effects of a higher feeding level and delayed slaughter on carcass traits.

Responses of lactating sows to food level

ABSTRACTEighty crossbred sows, following a standard feeding regime in pregnancy, received daily either 2·0, 3·5. 5·0 or 6·5 kg diet containing 130 g digestible crude protein, 8·0 g lysine and 13·1 MJ digestible energy per kg over a 28-day lactation to produce variation in body fatness and live weight. Sows on the highest level of feeding gained 13 kg and lost some 3 mm backfat between farrowing and weaning; corresponding changes on the lowest level of feeding were –31 kg and –9 mm backfat. Live weight of the litter at weaning was positively related to sow daily food allowance in lactation, but the major benefit of increasing lactation food allowance was in reducing the rate of maternal body weight and fatty tissue loss. These effects were described by the regression equations: maternal live-weight change in lactation (kg/day) = —1·7+0·34 lactation food intake (kg/day); maternal backfat change in lactation (mm LJSP2) = —0·40+0·05 lactation food intake fkg/day). Sows ingesting less food in lactation catabolized proportionately more body tissue to maintain milk yield and piglet growth, although they achieved this imperfectly, having lighter litters at weaning. Calculation of an overall net balance, taking into account the need subsequently to replenish tissues catabolized in lactation and ensuring efficient rebreeding of the sow, favoured a lactation feeding strategy towards ad libitum.

The Influence of Different Protein Supply and Feeding Level on pH, Ammonia Concentration and Microbial Protein Synthesis in the Rumen of Cows

Abstract Rumen ammonia concentration and pH was measured every second hour throughout 24 hours in an experiment including 33 periods with 2–5 rumen and duodenal cannulated cows. The calculated microbial non ammonia nitrogen synthesis was related to the mean NH3 concentration the hours with an NH3 concentration below 2, 5, 10, 15 and 20 mg NH3-N per 100 ml rumen fluid and the calculated protein balance in the rumen (PBV). The results showed no influence on rumen NH3 concentration of feeding the same ration composition on two levels, although the pH was significantly depressed by the higher feeding level. There was good agreement between the calculated PBV and the measured mean NH3-concentration in the rumen. The microbial protein synthesis per kg totally digested carbohydrates was not influenced by the PBV or NH3 concentration within the observed range in the experiments. The results further showed, that there is a significant variation in the microbial protein synthesis which can neither be described to t...

A model of growth and growth composition for beef bulls of different breeds

A biological model was constructed to simulate growth and growth composition of beef bulls representative of different breed types (small, medium and large) as affected by feeding level. Main starting points were breed-specific prediction of average daily lean gain and general concepts about protein and fat deposition. Growth, fat and protein deposition in the carcass and empty body were simulated on a daily basis. The model was validated on a separate data set. On a restricted feeding regimen differences between small and large beef breeds were small, but at a high feeding level large breeds grew faster and deposited less fat. Breed differences were sensitive to assumed maintenance requirements. The model provides a method to evaluate various measures of biological efficiency for alternative combinations of breeds and feeding levels.

Studies on reproduction of Javanese thin-tail ewes

Development of puberty (oestrus with ovulation) in two groups of 13 Javanese thin-tail (JTT) ewe lambs was studied from weaning at 13 weeks of age. The animals were fed ad lib. freshly chopped elephant grass plus either sufficient concentrate to grow at about 50 g per day (L) or ad lib. (H) concentrate from weaning to 5 weeks post-conception, and then studied through two pregnancies while on common feeding levels (Experiment 1). In Experiment 2, reproduction was studied in two groups of 13 JTT lambs which had been reared together and were given high or low nutrition from 5 weeks after their first conception until weaning of their second crop of lambs. The ewe lambs in Experiment 1 grew at 44 and 87 g per day (P < 0.01) for groups L and H respectively. Faster growth was associated with a younger age at first ovulation (190 v. 253 days), but differences in liveweight at first oestrus, first ovulation and puberty were marginal. Liveweight differences associated with differential feeding levels during rearing in Experiment 1 did not persist throughout the experimental period. Continuous high level feeding from early pregnancy (Experiment 2) resulted in a higher liveweight, and this was associated with higher ovulation rate (2.1 v. 1.6, P < 0.05) and an increase in the incidence of multiple births. However, this advantage in reproductive traits in the high feeding level group ewes was offset by higher wastage of ova (49 v. 20%) and higher pre-weaning lamb mortality (55 v. 33%). Average daily milk yield was non-significantly higher in the H group than in the L group in both lactations. In both experiments, improved feeding levels during rearing or thereafter reduced post-lambing re-breeding intervals. It was concluded that, while the JTT breed has unusually high, reproductive ability under low feeding regimes, most components of reproduction can be increased by strategic nutritional inputs.

The value of whole cottonseed in a wheat-based maintenance ration for sheep

The effects of fuzzy whole cottonseed (WCS) on the performance and health of sheep were examined. Thirty 2-year-old Merino wethers were divided into 3 equal groups and offered maintenance rations for 138 days, with whole wheat grain to WCS ratios of 100:O (diet A), 75:25 (B) and 50:50 (C). Liveweight changes for diets A, B and C were -0.3, +4.4 and +3.0 kg respectively, and were significantly (P<0.05) greater on WCS diets. Wool growth rates were also significantly (P< 0.01) improved by the addition of WCS, with treatment means being 0.65 (diet A), 0.82 (B) and 0.88 mg/cm2.day (C). Digestibility of DM in diet C (677 g/kg) was significantly (P< 0.001) lower than in diets A (782) and B (777 g/kg), perhaps because of increased fibre and oil in the ration. Subclinical anaemia and muscle damage were evident in animals given WCS by days 43 and 127 respectively. Post mortems and histological examination revealed renal haemosiderosis in sheep given WCS, with increased severity at 50% inclusion in the ration. Despite the reduction in digestibility and the subclinical effects on health, at least 25% WCS can be safely included in a wheat-based maintenance ration for wethers and this ration has production advantages over wheat alone. Caution is advised in feeding higher levels of WCS or feeding such a ration for more than 5 months.

The effects of genotype and post-weaning nutrition on compensatory growth in cattle reared as singles or twins

ABSTRACTThirty-five Charolais × Blue-Grey and Charolais × (Hereford × Friesian) weaned suckled calves which had been reared as either singles or twins and 19 single-reared Luing and Charolais × Luing weaned suckled calves were given silagead libitumsupplemented with either 0·75 or 2·5 kg rolled barley per day during the post-weaning winter. During summer the cattle continuously grazed perennial ryegrass swards. The high level of barley supplementation increased winter live-weight gain by 0·25 kg/day (P< 0·001). During summer the cattle from the low level of feeding gained weight at 0·09 kg/day (P< 0·05) faster than those from the high level of feeding. However, by the end of the summer grazing period the cattle on the low level of feeding were proportionately only 0·97 the weight of the animals on the high level of feeding.During winter the performance of all genotypes was similar, but at pasture the Luing cattle gained less weight (P< 0·01) than the single-reared Charolais-cross genotypes.Twin-reared cattle took 55 days longer to reach slaughter condition, but produced carcasses of equal weight and fatness to those from single-reared cattle.The twin-reared cattle on the high level of feeding and the single-reared cattle on the low level of feeding attained a similar weight, body condition and ultrasonic backfat at turn-out. Thereafter, their herbage intakes and live-weight gains were identical suggesting that previous level of feeding per se is unimportant in determining an animal's subsequent intake and performance. Rather it is the body composition at a given age, irrespective of the pathway followed to attain that composition, that determines performance thereafter. It is also suggested that the inability of cattle to compensate for a reduction in level of nutrition during the first 3 to 4 months of life is due to the lack of potential for fat deposition, and there is thus limited opportunity for nutritional manipulation of body composition at that age.

Effects of body condition, food intake and temporary calf separation on the duration of the post-partum anoestrous period and associated LH, FSH and prolactin concentrations in beef cows

ABSTRACTAn experiment was conducted to examine factors affecting the length of the post-partum anoestrous period and associated effects on LH, FSH and prolactin. Forty-six cows (24 Hereford × Friesian and 22 Blue-Grey) ranging in body condition score at calving from 1·50 to 2·75 were used. They were individually fed chopped barley straw and concentrate at either 50 (low) or 91 (high) MJ metabolizable energy per day from calving. At 34 days post partum half the cows were separated from their calves for 48 h. The duration of the post-partum anoestrous period was estimated from progesterone concentrations in thrice weekly blood samples. Blood samples were collected every 20 min for 10 h periods immediately prior to calf separation, during the last 10 h of calf separation and 1 week later. All samples were analysed for LH, and every third sample was analysed for FSH and prolactin.There were no significant effects of genotype, feeding level or calf separation on the length of the post-partum anoestrous period. There was a negative association between body condition score at calving and the length of the anoestrous period, with each unit increase in body condition score reducing the anoestrous period by 43 (s.e. 20) days. There was some evidence that feeding level affected the number of thin cows (body condition score ≤2·25 at calving) which were still acyclic at the end of the experiment, but not the number of fat cows (body condition score ≥2·5 at calving).FSH levels were not affected by any of the factors examined. Prolactin concentrations were higher in fatter cows, in cows on the higher level of feeding and in Blue-Grey cows. Prolactin concentrations decreased during the period of calf separation. Genotype and feeding level had no effect on LH concentration or LH pulse frequency. LH pulse frequency was increased (P < 0·05) during the period of calf separation, but there was no effect 1 week later. There was a significant positive relationship between LH puise frequency and body condition score at calving in two of the three sampling periods.It is suggested that the effect of body condition on the duration of the post-partum anoestrous period i s mediated through effects on LH pulse frequency.

Increase in mouse liver weight following feeding of ammonium perfluorooctanoate and related fluorochemicals

The weight of the mouse liver following feeding of ammonium perfluorooctanoate, ammonium perfluorononanoate, Telomer B ammonium sulfate, and WG-III was increased in a dose-dependent manner. Dietary levels of 3 ppm or greater ammonium perfluorooctanoate for either 14 or 21 days produced a significant elevation in liver weight both on an absolute and on an organ/body weight ratio basis. Similarly, ammonium perfluorononanoate-produced significant increases at the lowest level tested, 3 ppm. Telomer B ammonium sulfate and WG-III also produced liver weight increases but at higher feeding levels. The striking increase in liver weight following relatively short-term exposures in mice makes this a useful screening test for comparing the liver-enlarging capacity of ammonium perfluorooctanoate and related fluorochemicals.

Carcass composition of veal calves dependent on genotype and feeding level

ABSTRACTDutch Friesian purebred and Holstein Friesian-Dutch Friesian crossbred veal calves were used to study effects of genotype and feeding level on carcass composition. Carcass analyses were carried out on a total of 56 calves of two genotypes. Calves were reared for 22 weeks and given food dependent on age. From 1 to 16 weeks calves were given the same amount of milk replacer. At week 16, calves were assigned to either a high or low feeding level. Total energy intakes for the two groups were 5062 MJ metabolizable energy (ME) and 5408 MJ ME, respectively. Carcass weight and carcass composition traits showed no significant interaction between genotype and feeding level. Dutch Friesians had higher lean: bone ratios than Holstein Friesian crossbreds (3·85 v. 3·67). Differences between the two genotypes for fat and lean proportions in the carcass were not significant. Average proportions for lean and fat were 653 and 134 g/kg.Differences between the two feeding levels for carcass composition were significant. Calves on the low feeding level had 655 g lean and 131 g fat per kg, while calves on the high level had 645 g lean and 143 g fat per kg.The influence of the dissection technique on the differences in lean and muscle proportion between groups was studied on 18 carcasses using a standardized butcher's method (the Institute of Animal Husbandry (IVO) standard method) and the European Economic Community (EEC) reference method for beef. Average proportion of lean was 640 g/kg by the IVO method and of muscle was 557 g/kg by the EEC method. The difference between the two genotypes for lean proportion was smaller by the' EEC method due to the more complete separation between muscle and fatty tissue. Dutch Friesians had more intermuscular fat than Holstein Friesian crossbreds. Results of the EEC reference method indicate differences between the two feeding levels for fat as well as for protein deposition.