Diet selection of sheep: sodium bicarbonate, but not the offering of hay, modifies the effect of urea on diet selection

2002 ◽  
Vol 74 (2) ◽  
pp. 357-367 ◽  
Author(s):  
S. M. James ◽  
I. Kyriazakis ◽  
G. C. Emmans ◽  
B. J. Tolkamp
Keyword(s):  
Sodium Bicarbonate ◽  
Live Weight ◽  
Diet Selection ◽  
Metabolizable Energy ◽  
Fresh Matter ◽  
Total Food Intake ◽  
Period 2 ◽  
Control Food ◽  
Selection Of

AbstractThe hypotheses tested were that the expected preference of sheep for a food with adequate rumen degradable protein (RDP) supplemented with urea would be reduced both by the addition of a buffer (sodium bicarbonate (SB)) and by offering ad libitum access to hay. A control food (C), calculated to be adequate in its ratio of effective RDP to fermentable metabolizable energy (fME), was formulated. Other foods were made by adding 12·5 (U1) or 25 (U2) g urea per kg fresh matter (FM) to C and 20 g SB per kg FM to C, U1and U2. The acid buffering capacity (ABC) of each food was measured in vitro. The experiment consisted of two successive periods, each of 4 weeks. Ninety-eight female, Texel ✕ Greyface sheep were randomly allocated to 14 groups each with seven animals. Groups 1 to 6 were offered one of: C, U2, C + SB, U2+ SB, C with hay or U2with hay throughout the experiment. Groups 7 to 10 were offered the choices of C v. U1or C v. U2, either with or without hay in a change-over design; animals that received hay during period 1 (groups 8 and 10) did not do so during period 2 and vice versa (groups 7 and 9). Groups 11 to 14 (no. = 7) were offered the choices of C v. U1or C v. U2, either with or without SB supplemented to both foods, in a change-over design. Adding either urea, or SB, or both to C had no effects on intake or live-weight gain when offered alone. Both supplements significantly (P 0·001) increased the ABC of food C. Throughout the experiment hay consumption was very low (overall mean: 23 (s.e. 2·5) g hay per sheep day). Offering hay caused no change in the preference for the urea-supplemented foods. Sheep offered the choices C v. U1or C v. U2, with neither hay nor SB, selected 0.466 (s.e. 0·036) and 0.588 (s.e. 0·025) kg/kg total food intake (TFI) of U1and U2respectively. The proportions of the urea-supplemented foods were significantly reduced (P 0.01) by SB supplementation: to 0.348 (s.e.0·045) and 0·406 (s.e.0·059) kg/kg TFI of U1and U2respectively. The effect of SB addition on the diet selection of sheep could be due to its buffering properties. When SB is added to both foods the need for urea to be used as a buffer is reduced with a consequent decrease in the proportion selected as the urea-supplemented food. Effects of diet on buffering may override other diet selection objectives, such as the avoidance of an excess intake of RDP.

The effect of subclinical intestinal nematode infection on the diet seletion of growing sheep

1994 ◽  
Vol 72 (5) ◽  
pp. 665-677 ◽  
Author(s):  
I. Kyriazakis ◽  
J.D. Oldham ◽  
R.L. Coop ◽  
F. Jackson
Keyword(s):  
Feed Intake ◽  
Live Weight ◽  
Diet Selection ◽  
Metabolizable Energy ◽  
Protein Requirements ◽  
Intestinal Nematode ◽  
Ewe Lambs ◽  
Daily Rate ◽  
Reduced Rate ◽  
Selection Of

To test the hypothesis that subclinical gastrointestinal parasitism, associated with an impairment in N digestion and metabolism and a reduction in the voluntary feed intake (VFI), could affect the diet selection of sheep given a choice between two feeds that differed in their crude protein (CP) content, twenty-four Texel ×Scottish Blackface ewe lambs growing from 28 to 48 kg live weight (LWT) were given a daily dose of 2500 larvae of the intestinal nematode Trichostrongylus colubriformis; twenty-four similar lambs were used as uninfected controls. Six infected and six control lambs were given a free choice between two pelleted feeds (10·4 MJ metabolizable energy/kg), wilh different CP contents (90 (L) and 214 (H) g CP/kg fresh feed respectively). In addition, eighteen parasitized and eighteen control sheep were given access ad lib. to either feed L, or feed H, or their mixture M (164 g CP/kg; twelve per feed), in order to quantify the effects of the feeds when offered alone, and to test for any interactions between feed CP content and parasitism on the performance of the lambs. Intestinal parasitism reduced significantly (P < 0·001) both the rates of LWT gain (by 30%) and VFI (by 10%). The adult and developing parasitic forms took 4 weeks to establish and develop to a significant adult worm population (as judged by the faecal egg counts and blood variables) and until then there was no effect of parasitism on the performance of the lambs. The diet selection of the lambs given a choice between two feeds was similar between the two groups in the first 4 weeks of the experiment, but differed significantly (P < 0·05) in the second part of the experiment (4th week to the end). Thus, while parasitized lambs had a reduced rate of feed intake, by changing their diet selection they achieved a daily rate of CP intake similar to the control ones. However, since the parasitized lambs had a reduced rate of LWT gain, they also consumed a higher total amount of CP to reach the same LWT. It is concluded that sheep infected daily with a small number of larvae of T. colubriformis and given a choice between two feeds that differ in their protein contents are able to modify their diet selection in order to meet the increased protein requirements resulting from such an infection.

Diet selection of sheep: effects of adding urea to foods with different protein contents

2001 ◽  
Vol 73 (1) ◽  
pp. 183-195 ◽  
Author(s):  
S. M. James ◽  
I. Kyriazakis ◽  
G. C. Emmans
Keyword(s):  
Weight Gain ◽  
Live Weight ◽  
Diet Selection ◽  
Fresh Matter ◽  
Live Weight Gain ◽  
Beneficial Effects ◽  
Urea Content ◽  
General Preference ◽  
D 12 ◽  
Selection Of

AbstractTwo experiments were conducted in which growing sheep were given choices between foods differing in their contents of urea. The crude protein (CP) contents of both of the foods of the pair were also varied. The hypothesis tested was that the diets selected would be those that met the effective rumen degradable protein (eRDP) requirements of the animals and would avoid excess consumption of eRDP. Three basal foods, differing in CP were formulated. D was designed to be deficient in CP with 80 g CP and 58 g eRDP per kg DM; H was calculated to be adequate with 159 g CP and 114 g eRDP per kg DM; P had excess with 210 g CP and 148 g eRDP per kg DM. Other foods were made by adding 12·5 or 25 g urea per kg fresh matter to each of the three basal foods to make a further six foods. In both experiments Texel✕Greyface female sheep were used. In experiment 1, 34 sheep weighing 37·2 (s.d. 1·85) kg were randomly allocated to one of six groups and each group was offered a choice between a pair of foods. Groups 1 to 3 were offered pairs in the D series (Dv. D + 12·5 g urea per kg (no. = 6), Dv. D + 25 g urea per kg (no. = 6) and D + 12·5 g urea per kg v. D + 25 g urea per kg (no. = 5)). Groups 4 to 6 were offered the same pairs of foods but with H instead of D. In experiment 2, 96 sheep weighing 29·8 (s.d. 3·37) kg were randomly allocated to one of 12 groups. Groups 1 to 6 (no. = 6) were allocated a single food (D, D + 25 g, H, H + 25 g, P or P + 25 g urea per kg) throughout the experiment. Groups 7 to 12 were given a choice (no. = 10) between two foods. One food of the pair was the basal D, H or P. The other food was the same basal food supplemented with either 12·5 or 25 g urea per kg. On the single foods adding urea to D resulted in an increase in food intake and live-weight gain suggesting that D was deficient in eRDP. Adding urea to either H or P had no beneficial effects on intake or live-weight gain. This suggests that both contained sufficient eRDP in relation to energy. Across all choice treatments in both experiments there was a highly significant preference (P< 0·01) for the food with the higher urea content. In experiment 1 0·62 (s.e. 0·04) of the diet selected was the food with the higher urea content. In experiment 2 the figure was 0·64 (s.e.0·03). The general preference for the food with the higher urea content was unaffected by the CP contents of the foods used. The results do not support the hypothesis that sheep will avoid excess eRDP when given a choice and suggest that eRDP may not be a relevant dimension in diet selection in the conditions of these experiments.

scholarly journals Diet selection in sheep: The role of the rumen environment in the selection of a diet from two feeds that differ in their energy density

1995 ◽  
Vol 74 (1) ◽  
pp. 39-54 ◽  
Author(s):  
S. D. B. Cooper ◽  
I. Kyrizakis ◽  
J. V. Nolan
Keyword(s):  
Energy Density ◽  
Feed Intake ◽  
Latin Square ◽  
Live Weight ◽  
Diet Selection ◽  
Metabolizable Energy ◽  
Daily Rate ◽  
Carry Over ◽  
And Control ◽  
Selection Of

The effect of the energy density (ED) of feeds offered as a choice on the diet selection of sheep, and the relationship between the rumen environment and the diet selected from feeds of different ED were investigated in two experiments. In the first experiment two feeds, L and H, and their mixture M (3:1 w/w) were formulated. All feeds had similar calculated metabolizable protein: metabolizable energy (ME) ratios, but differed in ED (7·4, 8·1 and 10·1 MJ ME$sol;kg fresh feed for L, M and H respectively). The feeds were offered ad lib. either singly or in paired choices (L/M, L/H and M/H; n6 per treatment) to growing sheep. Although the rate of live-weight (Lwt) gain on feed H was higher than on feeds L or M, and the daily rate of feed intake lower, the sheep on feed choices did not consume only feed H. Instead they selected a mixture of both feeds offered, such that the total amount of H consumed per kg fresh feed was similar on choices L/H and M/H. The rate of Lwt gain of sheep on choices L/H and M/H was not different from that achieved on feed H alone. In the second experiment the choice L/H was offered to fistulated sheep (10 months of age, mean Lwt 57·5 kg) in an 8×8 Latin square, with 7 d periods. Treatments were infusions into the rumen (total volume 1 litre) over 4 h on days 1–4 of each period of acid (HC1; Acid 1, 400; Acid 2, 300 and Acid 3, 200 mmol/l), alkali (NaOH; Alk 1, 316; Alk 2, 212 and Alk 3, 109 mmol/l) and control (NaCl; Con 1, 315 and Con 2, 209 mmol/l). Infusate osmolalities (mOs/kg) were 795 (Acid 1), 585 (Acid 2, Alk 1 and Con 1), 390 (Acid 3, Alk 2 and Con 2) and 200 (Alk 3). Infusion treatment significantly affected the diet selection of the sheep (P < 0·05) according to the osmolality of infusate, but not according to rumen pH. During infusions intake of feed H tended to decline with increasing treatment osmolality, whereas intake of L remained constant. The effects on diet selection and feed intake were of a short duration with no carry-over effects. These results show that sheep given a choice between two feeds of different ED select a substantial quantity of the low-ED feed; this diet selection is affected by short-term manipulations of their rumen environment, in a manner that is consistent with the maintenance of effective rumen conditions.

scholarly journals Reduction of body-weight gain enhances in vitro embryo production in overfed superovulated dairy heifers

Reproduction ◽  
2006 ◽  
Vol 131 (4) ◽  
pp. 783-794 ◽  
Author(s):  
S Freret ◽  
B Grimard ◽  
A A Ponter ◽  
C Joly ◽  
C Ponsart ◽  
...  
Keyword(s):  
Weight Gain ◽  
Dietary Intake ◽  
Live Weight ◽  
Reproductive Hormones ◽  
Embryo Production ◽  
Live Weight Gain ◽  
Dairy Heifers ◽  
Period 2 ◽  
Significant Difference

The aim of our study was to test whether a reduction in dietary intake could improve in vitro embryo production in superovulated overfed dairy heifers. Cumulus–oocyte complexes of 16 Prim’ Holstein heifers (14 ± 1 months old) were collected by ovum pick-up (OPU), every 2 weeks following superovulation treatment with 250 μg FSH, before being matured and fertilized in vitro. Embryos were cultured in Synthetic Oviduct Fluid medium for 7 days. Heifers were fed with hay, soybean meal, barley, minerals and vitamins. From OPU 1 to 4 (period 1), all heifers received individually for 8 weeks a diet formulated for a 1000 g/day live-weight gain. From OPU 5 to 8 (period 2), the heifers were allocated to one of two diets (1000 or 600 g/day) for 8 weeks. Heifers’ growth rates were monitored and plasma concentrations of metabolites, metabolic and reproductive hormones were measured each week. Mean live-weight gain observed during period 1 was 950 ± 80 g/day (n = 16). In period 2 it was 730 ± 70 (n = 8) and 1300 ± 70 g/day (n = 8) for restricted and overfed groups respectively. When comparing period 1 and period 2 within groups, significant differences were found. In the restricted group, a higher blastocyst rate, greater proportions of grade 1–3 and grade 1 embryos, associated with higher estradiol at OPU and lower glucose and β-hydroxybutyrate, were observed in period 2 compared with period 1. Moreover, after 6 weeks of dietary restriction (OPU 7), numbers of day 7 total embryos, blastocysts and grade 1–3 embryos had significantly increased. On the contrary, in the overfed group, we observed more <8 mm follicles 2 days before superovulation treatment, higher insulin and IGF-I and lower nonesterified fatty acids in period 2 compared with period 1 (no significant difference between periods for embryo production). After 6 weeks of 1300 g/day live-weight gain (OPU 7), embryo production began to decrease. Whatever the group, oocyte collection did not differ between period 1 and 2. These data suggest that following a period of overfeeding, a short-term dietary intake restriction (6 weeks in our study) may improve blastocyst production and embryo quality when they are low. However, nutritional recommendations aiming to optimize both follicular growth and embryonic development may be different.

Diet selection in pigs: choices made by growing pigs given foods of different protein concentrations

1990 ◽  
Vol 51 (1) ◽  
pp. 189-199 ◽  
Author(s):  
I. Kyriazakis ◽  
G. C. Emmans ◽  
C. T. Whittemore
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Protein Concentration ◽  
Live Weight ◽  
Diet Selection ◽  
Growing Pigs ◽  
Growth Potential ◽  
Feeding Method ◽  
Total Food Intake ◽  
Total Food

ABSTRACTTo test the proposition that growing pigs, when given a choice between two foods, are able to select a diet that meets their requirements, and to investigate the rules of diet selection, four foods (L, A, B and H) with similar energy yields, but different concentrations of crude protein (CP) (125, 174, 213 and 267 g CP per kg fresh food respectively) were formulated. The four foods were offeredad libitumeither singly, or as a two-way choice using all the six possible pairs, to 40 individually caged pigs from 12 to 30 kg live weight. On the single foods the rate of food intake fell from 1001 to 971 to 961 to 868 (s.e.d. 40) g/day (F < 0·05) as the protein concentration of the foods increased from L to H; the growth rate followed an opposite trend (492, 627, 743 and 693 (s.e.d. 31) g/day respectively;P< 0·01). When the pigs had to select between two foods limiting in protein (L and A) the less limiting one was preferred (710 (s.e. 200) g A per kg total food intake; the protein concentration of the selected diet was 160 (s.e. 10) g CP per kg). On the choice between B and H (a choice between a food with protein concentration close to requirements and a food with protein excess) the lower food was markedly preferred (928 (s.e. 4) g B per kg total food intake; the protein concentration of the selected diet was 218 (s.e. 1) g CP per kg). When the animals were given a choice between two foods, a combination of which was non-limiting (pairs LB, LH, AB and AH), the protein concentrations of the selected diets were not different between treatments (208, 204, 202 and 205 (s.e.d. 13) g CP per kg respectively) and they also declined systematically with time and weight. The growth rate of the animals on these pairs were 752, 768, 769 and 763 (s.e.d. 54) g/day (P > 0·05), which were not significantly different from the highest growth rate achieved on a single food. The results suggest that pigs, when given a choice between a suitable pair of foods, are able to choose a balanced diet and to change its composition to reflect their changing requirements. The choice-feeding method may well be useful as an effective and economic way of estimating and meeting requirements, and of measuring the growth potential of pigs.

scholarly journals The effect of rumen adaptation to oxalic acid on selection of oxalic–acid–rich plants by goats

2000 ◽  
Vol 83 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Alan J. Duncan ◽  
Pilar y ◽  
Sheila A. Young
Keyword(s):  
Oxalic Acid ◽  
Live Weight ◽  
Diet Selection ◽  
Adaptation Period ◽  
Gelatin Capsules ◽  
Secondary Plant Compounds ◽  
Internal Markers ◽  
Plant Compounds ◽  
Selection Of ◽  
Secondary Plant

Rumen microbial degradation is an important route for detoxification of secondary plant compounds encountered in the diets of free-grazing ruminants. Exposure to diets containing particular secondary plant compounds can lead to increased rates of secondary compound degradation in the rumen. An experiment was conducted to determine whether rumen adaptation to oxalic acid would influence the diet selection of goats offered choices between plant species differing in their oxalic acid content. Twelve adult female goats were divided into two groups of six animals each. One group received a daily oral dose, in gelatin capsules, of 0·6 mmol oxalic acid/kg live weight per d throughout the experiment while the other group received placebos consisting of empty gelatin capsules. After an adaptation period of 8 d, the animals were allowed to graze a mixture of spinach (rich in oxalic acid) and cabbage (low in oxalic acid) for 7 h/d on two consecutive days per week during four consecutive 1-week periods. Intervening days were spent on grass pasture. Diet composition and intake were measured using cuticular wax n−alkanes as internal markers. Results showed that adapted goats included a higher proportion of spinach in their diet (P < 0·05) although absolute intakes of spinach were the same for the two groups. Goats in the oxalic-acid-adapted group consumed less cabbage than control animals (P < 0·05) suggesting that adaptation to oxalic acid at the rumen level may have interfered with detoxification of cabbage-derived secondary plant compounds. Voluntary intake increased progressively through the four experimental periods (P < 0·001) with a tendency for higher intakes among control than among adapted animals (P < 0·1). The experiment demonstrates how differences in the rate of degradation of secondary plant compounds may influence diet selection in ruminants.

The apparent digestibility of Atriplex barclayana and its effect on nitrogen balance in sheep

1992 ◽  
Vol 54 (2) ◽  
pp. 259-264 ◽  
Author(s):  
R. W. Benjamin ◽  
E. Oren ◽  
E. Katz ◽  
K. Becker
Keyword(s):  
Nitrogen Concentration ◽  
Latin Square ◽  
Nitrogen Retention ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Energy Concentration ◽  
Apparent Digestibility ◽  
The Mean

AbstractAn in vivo digestibility trial was conducted by feeding sheep the leaves, fruits and twigs of Atriplex barclayana in a proportion roughly equivalent to that eaten by sheep grazing freely in Atriplex plantations. Four treatments were imposed on each of four sheep in a 4 × 4 Latin-square experimental design: Atriplex offered alone or with 100, 200 or 300 g/day tapioca meal.The mean apparent digestibility of the Atriplex dry matter (DM) and organic matter (OM) consumed were 0·59 and 0·56, respectively. Addition of tapioca to the Atriplex in the diet did not improve these digestibility coefficients. The low OM content of 760 g/kg together with its digestibility of 0·56 resulted in the Atriplex having a low metabolizable energy concentration of 6·28 MJ per kg DM. The in vitro apparent DM digestibility of Atriplex was approximately 0·09 higher than the in vivo apparent digestibility.The mean nitrogen concentration of the Atriplex DM was 16·6 g/kg, and its apparent digestibility 0·73, which was not improved by the addition of tapioca to the diet. Nitrogen retention of the sheep eating only Atriplex was proportionately 0·17 of the nitrogen intake. The addition of 300 g tapioca improved nitrogen retention to 0·27 but was not significantly different from the other treatments.Water intake and urine excreted were as high as 14 and 12 I/day respectively, for an Atriplex DM intake of about 1300 g/day. During the experiment the sheep only maintained live weight, despite daily intakes of up to 1200 g Atriplex DM and up to 300 g tapioca.

scholarly journals Diet selection in sheep: the ability of growing lambs to select a diet that meets their crude protein (nitrogen × 6.25) requirements

1993 ◽  
Vol 69 (3) ◽  
pp. 617-629 ◽  
Author(s):  
I. Kyriazakis ◽  
J. D. Oldham
Keyword(s):  
Weight Gain ◽  
Feed Intake ◽  
Protein Intake ◽  
Crude Protein ◽  
Energy Content ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Protein Nitrogen ◽  
Se 33 ◽  
Selection Of

To test the proposition that sheep are able to select a diet that meets their crude protein (N × 6.25; CP) requirements, feeds L, A, B, C and H with the same energy content (11 MJ metabolizable energy/kg feed) but different CP contents (78, 109, 141, 172 and 235 g CP/kg fresh feed respectively) were formulated. In addition, feed U, which was feed L plus 21.4 g urea/kg (CP content 132 g/kg), was also made. The feeds were offered ad lib. either singly (n 4 per treatment) or as a choice between feed H and another feed (pairs LH, AH, BH, CH and UH; n 9 per feed pair) to individually penned Suffolk × Scottish mule wether lambs, over the live-weight range 25–45 kg. On the single feeds the rates of live-weight gain were 273, 326, 412, 418, 396 and 407 g/day (SE of difference (SED) 34; P < 0.01) and protein (excluding wool) gain were 27, 32, 44, 45, 41 and 39 g/d (SED 4; P < 0.001) for feeds L, A, B, C, H and U respectively. When sheep were given a choice between a feed below (L or A) and a feed above their CP requirements (H; as judged by the single-feeding treatments) the CP concentration selected was not different between the two pairs: 131 (SE 4) v. 133 (SE 4) g CP/kg feed for pairs LH and AH respectively. On the choices BH and CH (a choice between two feeds above requirements) the feed lower in CP was constantly preferred (874 (SE 33) and 910 (SE 33) g feed B and C respectively per kg total feed intake; CP selected was 157 and 178 g CP/kg respectively). However, this was not the case with the UH choice on which sheep consumed only 599 (SE 61) g feed U/kg total feed intake, resulting in a selection of a higher CP in their diet (173 g CP/kg). The live-weight gains of the animals given a choice between two feeds were 416, 387, 415, 410 and 383 g/d (SED 37) and protein gains were 45, 40, 46, 50 and 43 (SE 7) for pairs LH, AH, BH, CH and UH respectively, which were comparable with the best performance achieved on a single feed. The results suggest that sheep were able to select a diet that meets their CP requirements and avoid, at least to a certain extent, excess of protein intake. It is also possible that sheep discriminate against a property of feed U, such as an excess of urea, when this feed is paired with a feed high in CP.

A comparison of growth, food efficiency and carcass characteristics of single and twin beef calves derived by embryo transfer

1993 ◽  
Vol 57 (1) ◽  
pp. 81-89 ◽  
Author(s):  
D. C. Patterson ◽  
R. W. J. Steen ◽  
D. J. Kilpatrick
Keyword(s):  
Initial Period ◽  
Carcass Characteristics ◽  
Live Weight ◽  
Twin Plane ◽  
Metabolizable Energy ◽  
Beef Calves ◽  
Period 2 ◽  
Weight Gains ◽  
Main Period ◽  
Compensation Index

AbstractAn experiment was designed to examine the interaction between birth status and plane of nutrition of calves in relation to postnatal and lifetime performance. The experiment was a 2 × 2 × 2 factorial arrangement of birth status (single and twin), plane of nutrition from birth to 16 weeks (period 1) and plane of nutrition from 16 weeks to slaughter at a mean live weight of 530·4 (s.e. 0·13) kg (period 2). The planes of nutrition were control and low with metabolizable energy (ME) intakes of 32·1 and 21·4 (s.e. 0·46) MJ/day from birth to 16 weeks, and 73·9 and 64·1 (s.e. 0·95) from 16 weeks until slaughter. The birth weights of the single and twin-born calves were 47·2 and 39·7 (s.e. 0·90) kg respectively. There was no interaction between birth status and plane of nutrition in either main period and by 40 weeks of age the live weights of the twin calves were similar to those of the single-born calves. For period 1 plus period 2 the live-weight gains per unit of ME intake were 12·4 and 13·1 (s.e. 0·28) g/Mf for single and twin-born calves respectively. Although twins had slightly poorer carcass conformation and higher proportion of bone in the carcass, the concentrations of saleable meat and high-priced joints in the carcass were similar. Birth status had no effect on the ultimate pH of muscle. It is concluded that viable twins have similar beef producing potential to single-born calves.The control and low planes of nutrition imposed during the periods from birth to 16 weeks and 16 weeks to slaughter produced live-weight gains of 822 and 573 (s.e. 31·0) g/day, and 857 and 690 (s.e. 12·6) g/day respectively. Calves which had been on the low plane during the initial period had a compensation index of 0·30 by 64 weeks of age. Carcass measurements were not affected by the plane of nutrition during either period. Steers grew faster than heifers, had lower area o/m. longissimus dorsi but less separable fat and more bone in the forerib joint than heifers at equal carcass weight.

Evaluation of pasture for beef cattle from measurements of cell wall in separated leaf and stem fractions

1983 ◽  
Vol 100 (3) ◽  
pp. 513-518 ◽  
Author(s):  
K. W. Moir ◽  
J. P. Ebersohn
Keyword(s):  
Cell Wall ◽  
Dry Matter ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Dietary Energy ◽  
High Cell ◽  
Grazing Cattle ◽  
Weight Gains ◽  
Tropical Grass

SUMMARYThree pastures, pangola–clover, setaria, and tropical grass–legume, were grazed for a 9-month period by 12 steers of initial live weight of 199 kg on each. For the first 5 months live-weight gains were, respectively, 1·2, 0·76 and 0·43 kg per day, mostly higher than could be expected for estimated dietary energy concentrations of 10·1, 8·9 and 8·7 MJ of metabolizable energy (ME) per kg of dry matter. The high live-weight gains were not explained satisfactorily by dry-matter intakes as measured from faeces voided and dietary digestible dry matter, but were possible if published values for the requirements of ME for growth and fattening were too high. Cell wall, in vitro digested cell wall and nitrogen in separated leaf and stem fractions were useful indices for evaluating pasture for grazing cattle, but they did not predict live-weight gain.

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