Wheat Intake Research Articles

Production by wethers fed oats, wheat, and lupins, with dry annual pasture in north-eastern Victoria

An experiment was conducted at Rutherglen Research Institute in autumn 1979 to evaluate various grain supplements for the fattening of 18-month-old Merino wethers intended for the live export market. All sheep had mature, dry pasture, harvested during mid summer, freely on offer. This herbage contained 9% crude protein and was 47% digestible. Wheat, oats or lupins were fed as supplements at 0, 180, 360, 540 g/head.d and ad libitum. Mixed grain rations were also studied: lupins were fed at 0, 90, 180 and 270 g/head.d with either wheat or oats ad libitum. Wethers were fed these rations for nine weeks and fasted liveweight, wool growth, and body condition score were measured. Animals were then slaughtered and carcases weighed. Animal performance was positively related to the rate of grain intake. Ad libitum intakes of wheat and oats were low - 450 and 520 g/head.d respectively, and only maintained liveweights. in contrast, lupins fed ad libitum were consumed at 650 g/head.d, which resulted in significant increases in live and carcase weight - 4 kg and 3.8 kg respectively. Pasture intake was reduced by one third with all ad libitum grain rations. The addition of lupins at 180 g/head.d to wheat or oats increased the ad libitum intakes of the cereal grains to 550 and 650 g/head.d, respectively, with associated liveweight gains of 1.0 and 4.5 kg for the nine week period. Intake of cereal grains was generally low compared with that in other published reports; but all rations containing more than 10% lupins showed promise as supplements for fattening wethers.

NUTRITIVE VALUE OF WHOLE CROP SILAGE MADE FROM SEVEN CEREAL CULTIVARS

Seven cultivars of barley, oats and wheat were harvested at the mid-dough stage and stored in polyethylene-covered experimental silos of 700-kg capacity. Four steers weighing about 200 kg were fed each type of silage in order to determine voluntary intake and digestibility of energy and protein. The silages averaged 36.6% dry matter and 12.5% crude protein, with the wheat and barley silages containing significantly more protein than oat silage (P < 0.05). Digestibility of energy averaged 65.4%. The wheat and barley cultivars tended to contain higher digestible energy levels than oat cultivars. Digestibility of crude protein averaged 68.5% with no significant differences. Voluntary intake of dry matter (DMg/Wkg.75) was higher (P < 0.05) in oats than barley or most wheat cultivars. Intake of Glenlea wheat equalled Fraser oats and the unlicenced 1863–4 oat cultivar.

Whole wheat grain feeding of pregnant and lactating ewes and their lambs. 2. Lamb productivity from whole wheat diets with varying levels of sodium chloride and elemental sulphur supplements

Lambs born to ewes fed whole wheat grain were raised and fattened on whole wheat supplemented with varying levels of sodium chloride or elemental sulphur. Liveweights, wheat intakes, feed conversions and carcase weights were measured. Lamb birth weights increased with increasing quantities of energy, and of sodium chloride at high sulphur levels, offered to the ewe during late pregnancy. A weaning weight response to sodium chloride supplementation at high sulphur levels (P < 0.10) was substantially reduced when weaning weight was adjusted for ewe milk production. Lambs were successfully weaned at seven weeks of age to a diet of whole wheat grain. Their subsequent slaughter weights and carcase weights increased with sodium chloride supplementation up to levels of about 1.2 to 1.4 per cent. Little change occurred in the sodium chloride response when slaughter weight was adjusted for weaning weight. The importance of these results in relation to the mineral requirements of lambs fed whole wheat grain is discussed.

Whole wheat grain feeding of Merino ewes. 4. Changes in hepatic vitamin A concentration

In two experiments Merino breeding ewes were fed wheat in pens or small paddocks from joining to weaning. Three levels of wheat were examined in each experiment and at each wheat level one-half of the ewes received vitamin A, Injections of 1 million I.U. of vitamin A were given twice in the first experiment and four times in the second. Control groups of ewes were run at pasture or fed pasture hay. Ewes injected with vitamin A had higher hepatic concentrations of the vitamin than those unsupplemented. Wheat intakes, which ranged from 3.4-7.1 kg ewe-1 week-1, had no effect on either the rate of expenditure of hepatic vitamin A concentration or the extent of storage and absorption of the vitamin after dosing. Pregnancy and lactation did not significantly increase changes in hepatic vitamin A concentration. The relationship between hepatic vitamin A concentration and time was curvilinear in ewes fed wheat without vitamin A. The rate of loss was not different between experiments and amounted to 6.03 per cent per week.

Whole wheat grain feeding of Merino ewes. 3. Influence of level of wheat and vitamin A on wool growth in pregnancy and lactation

In experiment 1, ewes were fed three levels of wheat in pens, with or without vitamin A, from joining to weaning. The wheat levels ranged from 3.4 to 4.6 kg head-1 week-1. Control groups were run on native pasture. In experiment 2 three levels of wheat, which ranged from 3.9 to 7.1 kg head-1 week-1. were fed to ewes from joining to weaning. At each wheat level two groups were fed wheat in pens (wheat/ pen); another group was fed wheat in small paddocks (wheat/paddock). One of the wheat/pen groups received vitamin A. A control group was run at pasture. Vitamin A had no effect on wool traits except on wool yield in experiment 2. Clean wool weight and staple length increased linearly with increasing wheat intakes in both experiments. The relationship between fibre diameter and wheat level was linear in experiment 1 and curvilinear in experiment 2. In experiment 2 there were differences between wheat/pen and wheat/paddock groups in all the wool traits measured. In experiment 1, wool growth rate was reduced by 40 per cent in the wheat groups and by 44 per cent in the pasture groups during late pregnancy and lactation. In experiment 2, compared with early pregnancy, wool growth rate was reduced by 11 per cent and 31 per cent in the wheat groups during late pregnancy and lactation respectively.

Whole wheat grain feeding of Merino ewes. 1. Influence of level of wheat and vitamin A on water consumption, mortality and ewe liveweight

In experiment 1, three levels of wheat were fed twice weekly to groups of 120 ewes in pens from joining to weaning. The wheat levels were: Ll , 3.4; M1, 4.0 and HI, 4.6 kg (fresh weight) head-1 week-1 and at each level one half of the ewes received vitamin A. A control group was run at pasture. In experiment 2, three levels of wheat were fed, twice weekly to groups of ewes from joining to weaning. At each wheat level 140 ewes were in pens (wheat/pen) and one-half of these received vitamin A; 70 ewes were fed wheat in small paddocks (wheat/paddock). The wheat levels were: L2, 3.9; M2, 5.5 and H2, 7.1 kg (fresh weight) week-1. A control group was run at pasture. Water consumption by ewes in experiment 2 increased curvilinearly with increasing wheat intakes and linearly with temperature and advancing pregnancy. Ewe mortality was not different between treatments in experiment 1. In experiment 2, 24 per cent of ewes fed wheat in pens at the H2 level died between the start of lambing and weaning. Wheat level significantly influenced ewe liveweights. Vitamin A had no effect on the measurements made.

The Effect of Level of Feed Intake on Metabolizable Energy Values Measured with Adult Roosters

Two experiments were made with S.C.W.L. roosters to test the hypothesis that the apparent M.E. value of a feedingstuff is affected by the level of intake. In the first experiment the birds were starved for 18 hr. and then fed varying amounts of whole wheat. Excreta voided during the 24 hr. experimental period was collected quantitatively and assayed for gross energy. Energy voided as excreta increased in a linear manner as the intake of wheat increased. The apparent M.E. value also varied with wheat consumption according to the equation M.E. (kcal./g.) = 3.17X – 8.5/X where: 3.17 kcal./g. is the true M.E. value of the wheat; 8.5 kcal. represents the sum of the metabolic fecal and endogenous urinary energy losses; and X is the weight of wheat consumed (g.). A supplementary observation was that the metabolic fecal and endogenous nitrogen excretion of the roosters was 144 mg./kg./24 hr. In the second experiment corn oil was placed in the crops of starved roosters and the energy voided as excreta in 24 hr. was measured. The true M.E. value of the corn oil was 9.40 kcal./g. but the apparent value varied with intake. It is therefore concluded that the original hypothesis is correct. The findings of these experiments may explain some of the reported variations in M.E. data. A new approach to the assay for M.E. is proposed.

Protein Requirements of Man: Comparative Nitrogen Balance Response within the Submaintenance-to-maintenance Range of Intakes of Wheat and Beef Proteins

Sixteen young male students participated in two studies designed to determine the nitrogen balance response to beef or stone-ground, whole wheat protein over the submaintenance-to-maintenance range of protein intake. The objective of the studies was to evaluate the relative capacities of these proteins to meet the minimum protein needs in young adult males. A modified Latin-square design was used to allocate subjects to the four 15-day metabolic balance diet periods in each study. The last 10 days were used for fecal nitrogen determination and the last 5 days for evaluation of urinary nitrogen excretion. The diet periods were separated by a 4-day break period and began with 1 day on a "protein-free" diet. The levels of protien (N times 6.25) intake tested were 0.2, 0.3, 0.4, and 0.5 g/kg body weight/day in the beef study. The results have been compared with those obtained in a previous similar study with egg protein. The regression of estimated "true" nitrogen balance (Y) (mg N/kg/day) on nitrogen intake (X) (mg N/kg/day) was: Y equals 0.51(plus or minus 0.08)X minus 41.9(plus or minus 4.6) for beef and Y equals 0.27(plus or minus 0.06)X minus 33.6(plus or minus 5.0) for whole wheat protein. The amounts of beef and wheat proteins estimated to be requried to support body nitrogen balance in 97.5% of the population supplied 96 and 178 mg N/kg/day, respectively. The relative protein value of beef and wheat proteins, in comparison with egg protein, was 78 plus or minus 12 and 41 plus or minus 10, respectively. It is concluded that the variations in dietary protein quality should be taken into account in assessing the protein adequacy of diets for individuals and population groups.

Whole wheat grain feeding of pregnant and lactating ewes and their lambs. 1. The influence of energy, sodium chloride and elemental sulphur on ewe productivity

This experiment was designed to explore the influence of energy, sodium chloride and elemental sulphur on the productivity of pregnant and lactating ewes fed whole wheat grain diets. A central composite design was used to study the response over five levels of each factor. During the last 42 days of pregnancy, the energy treatments resulted in either maintenance of maternal body weights at about 42 kg, or losses of up to 5.5 kg. Ewe maintenance requirements were about 0.14 MJ ME kg-1 day -1 and their foetal requirement was 1 .I 5 MJ ME kg-1 day-1. Sodium chloride and elemental sulphur supplements had no influence on ewe liveweight change up to lambing, but wool growth increased with sulphur supplements of up to about 0.25 to 0.30 per cent. Energy intake and sodium chloride supplementation increased lamb birth weight. After lambing, ewes that had been offered low energy diets increased their liveweight gain and wheat intake with sulphur supplements whereas these supplements reduced the liveweight gain and wheat intake of ewes offered higher energy. Milk production measured on day 14 of lactation averaged 11 53 g day -1 and was not significantly influenced by treatment. These results are discussed in relation to the metabolism of pregnant and lactating ewes, and in the context of the composite design used.

Feeding steers high levels of oats and wheat: effects of substituting one grain for the other

Hereford and Shorthorn steers were fed in yards for an initial period of 63 days, (including a 20 day change-over period) during which chaff and either wheat or oat grain were fed ; then for 5 days one grain was gradually substituted for the other; a final period of 64 or 71 days of feeding then followed. Two levels of grain were examined, 60 and 90 per cent, and similar percentages of an equal mixture of both grains were fed unchanged throughout the entire period. No digestive disturbances resulted from the substitution of the grains. In both the initial and final periods the steers receiving 90 per cent wheat had significantly higher liveweight gains than those on oats (1.36 v. 0.72 � SE 0.122 and 1.60 v. 0.84 � 0.079 kg per day). These gains were associated with an intake of wheat significantly higher than that of oats in the final period only (8.13 v. 5.88 �. 0.337 kg per day) and a lower (not significant) feed conversion of 5.31 v. 8.47 � 0.671. Results for an equal mixture of both grains were intermediate between those obtained with the single grain diets. There were no differences between treatments at the 60 per cent grain level. The dressing percentage of steers finishing the experiment on wheat (54.5 � 00.4) was significantly higher than of steers finishing on oats (51.9) or on a mixture of the grains (52.4).

Whole wheat grain feeding of lambs. III. Rumen metabolic responses and animal physiological adjustment to mineral buffer supplements

An intensive 17-week study was made of nine rumen-cannulated crossbred lambs off pasture when given mineral buffer supplements as they were changed from lucerne chaff diets to diets of whole wheat grain plus 2 % of ground limestone. Diets were given ad libitum. Buffers were supplied during transition (period 11) and after transition (period III). The buffers were a 1/1/1/1 mixture of powdered disodium hydrogen phosphate, sodium bicarbonate, potassium bicarbonate, and calciuns hydrogen phosphate given as 2% of the grain offered (group B) and powdered alumirn~~m hydroxide (Al(OH)3) given as 1 % by weight of the grain ofiered (group C). The wheat gram diet was low in sodium (0 008%) and contained 1.50% nitrogen. Production responses to both mineral buffer treatments resulted. Soth buffer treatments increased the voluntary intake (P < 0.01) of wheat above that of the control animals. The rate of eating (g/hr) and pattern of eating did not differ significantly between groups, or between periods I (lucerne chaff) and 111 (post-transition). Groups B and C increased in liveweight to a greater extent than did control animals (P < 0 01) and had heavier carcasses (P <0.01). Results with the mineral mixture given to group B (above) confirm our earlier report. Ingestion of aluminium hydroxide was associated with abomasal ulceration. No significant differences were found between groups in any period for total volatile fatty acids in rumen liquor. Towards the end of period 111, animals given buffer had lower proportions of acetic and higher proportions of propionic acid than did control animals (P < 0.01). Hexanoic acid was detected in all rumen liquor samples obtained in period 111, sometimes in amounts equal to 17 % of total volatile fatty acids. Lactic acid was not detected in rumen liquor in period I, but was present in large amounts in all lambs during period 11, and in lesser but substantial amounts in all lambs during period III. Levels of lactic acid in the rumen liquor in animals receiving mineral buffer supplements fell at a faster rate during period I11 ?hall did levels in control animals. There was a significant decline in rumen pH values for all groups from period I to period III (P < 0.01). Significant rumen pH differences attributable to mineral buffer treatment were apparent (P < 0 05). Buffers were associated with a less acid rumen condition than found in control animals. Relative to control animals, animals given mineral buffers showed increases in rumen buffering capacity and salivary flow rates, and an increased buffering index of the total mixed saliva. Period effects were apparent. The saliva flow rates of control lambs fed on wheat were significantly increased compared with their flow rates on the roughage diet of lucerne chaff. In general, supplementation with aluminium hydroxide and with the mixed buffer respectively yielded similar patterns of response. It is concluded that responses were not primarily due to the sodium level of the diet per se, and that alterations in the animals' electrolyte and acid-base physiology induced by buffer treatment might be contributory factors. Various possible physiological mechanisms are discussed.

The feed intake of sheep supplemented with varying quantities of wheat while grazing pastures differing in herbage availability

Diets containing various quantities of lucerne chaff and wheat grain were given to three sheep in a digestibility trial. Daily faecal output was related to daily intakes of chaff and wheat by regression analysis. The partial regression coefficient for wheat was used to estimate the faecal output attributable to wheat in a grazing trial in which flocks of five sheep grazed at five stocking rates and received either 0, 100, 200, 300, or 400 g wheat per day. The sheep were allocated to treatments and periods at each stocking rate in a Latin square design. Herbage intake was estimated in each period. Herbage intake decreased when supplementary feeding or stocking rate was increased. Supplementary feeding increased the nutrient intake of grazing sheep by an average of 54% of the nutrient content of the wheat given. This percentage was greater when pasture availability was low. At high stocking rates the decline in herbage intake was less than at low stocking rates in absolute terms although greater when expressed as a percentage of the herbage intake of the unsupplemented sheep