scholarly journals Calcium and phosphorus requirements of the ewe during pregnancy and lactation

1983 ◽  
Vol 50 (3) ◽  
pp. 723-736 ◽  
Author(s):  
G. D. Braithwaite
Keyword(s):  
Research Council ◽  
Agricultural Research ◽  
Late Pregnancy ◽  
Early Lactation ◽  
Mineral Balance ◽  
Agricultural Research Council ◽  
Pregnancy And Lactation ◽  
Calcium And Phosphorus ◽  
Phosphorus Requirements ◽  
P Absorption

1. Mineral balance and radioisotope studies have been carried out to test the adequacyof the recent Agricultural Research Council (1980) recommendations for calcium and phosphorus for pregnant and lactating ewes. At the same time, P metabolism was compared throughout pregnancy and lactation in ewes fed according to these recommendations and in ewes fed a plentiful supply of dietary Ca and P.2. Bone mineral stores were mobilized in late pregnancy and early lactation, irrespective of the rate of P absorption. These stores were then replaced in mid- to late lactation in ewes given the plentiful Ca and P intake but not in the ewes given the restricted intake.3. Results suggest that these changes in bone stores occurred as a result of changes in Ca requirements rather than in P requirements, and that accretion of P into bone or resorption of P from bone occurred merely as a conseqence of this change in Ca requirements.Immediate demands for P for maintenance and fetal or milk production do not reflect net Pdemands, which also take into account changes in bone P metabolism.4. The rate of P absorption was directly related to net demands and the rate of endogenous excretion was inversely related to net demands.5. Absorption and endogenous faecal loss of P were also both directly related to P intake.6. A lack of dietary Ca, particularly in mid- to late lactation, makes it impossible to draw conclusions on the adequacy of the Agricultural Research Council (1980) recommendations for P. Results do suggest, however, that P requirements ought to be calculated according to net demands for P rather than immediate demands.

Phosphorus requirements of ewes in pregnancy and lactation

1986 ◽  
Vol 106 (2) ◽  
pp. 271-278 ◽  
Author(s):  
G. D. Braithwaite
Keyword(s):  
Research Council ◽  
Agricultural Research ◽  
Late Pregnancy ◽  
Experimental Period ◽  
Early Lactation ◽  
Agricultural Research Council ◽  
Pregnancy And Lactation ◽  
Phosphorus Requirements ◽  
P Absorption ◽  
Subsequent Replacement

SUMMARYThe adequacy of the Agricultural Research Council (1980) recommendations for phosphorus for pregnancy and lactation has been investigated in ewes given a plentiful supply of dietary calcium.The efficiency of absorption of P remained high and fairly constant throughout the whole experimental period and the rate of P absorption varied in direct relation to the P intake.The endogenous faecal loss of P also varied with P intake and at all stages of pregnancy and lactation was higher than the value assumed by the Agricultural Research Council (1980) in their calculations of P requirements.Bone mineral stores of Ca and P were lost in the normal way during late pregnancy and early lactation but were not replaced, as normal, in mid- to late lactation. At the end of the lactation, ewes were still in deficit of 125 g P and 100 g Ca.It is argued that the Agricultural Research Council (1980) recommendations for P, particularly in mid- to late lactation, are too low and it is recommended that future calculations of requirements for pregnancy and lactation allow for the inevitable loss and subsequent replacement of skeletal mineral stores and also for the increased endogenous faecal losses of P that appear inevitable at the high P intakes needed to meet the increased demands.

scholarly journals Calcium and phosphorus requirements of the ewe during pregnancy and lactation

1983 ◽  
Vol 50 (3) ◽  
pp. 711-722 ◽  
Author(s):  
G. D. Braithwaite
Keyword(s):  
Research Council ◽  
Agricultural Research ◽  
Late Pregnancy ◽  
Maximum Efficiency ◽  
Agricultural Research Council ◽  
Pregnancy And Lactation ◽  
Calcium And Phosphorus ◽  
Total Body ◽  
Phosphorus Requirements ◽  
Subsequent Replacement

1. Mineral balance and radioisotope studies have been carried out to test the adequacy of recent Agricultural Research Council (1980) recommendations for calcium and phosphorus for pregnant and lactating ewes. At the same time, Ca metabolism was compared throughout pregnancy and lactation in ewes restricted to these recommendations and in ewes given a plentiful supply of dietary Ca and P.2. Irrespective of their Ca intake, ewes were unable to absorb enough dietary Ca in late pregnancy and early lactation to meet the high demands, and skeletal stores of Ca were mobilized to make good the deficit.3. Whereas ewes given the plentiful intake absorbed enough dietary Ca in mid- to late lactation to replace their lost skeletal Ca stores, ewes given the restricted Ca and P intake did not and, at the end of lactation, were still in deficit of about 10% of their total body Ca.4. Since Ca absorption in the restricted ewes occurred at the maximum efficiency (66%) expected from a hay and concentrates diet, the Agricultural Research Council (1980) recommendations for Ca, particularly in mid-to late lactation, must be inadequate.5. It is suggested that in calculating requirements, allowance must be made for the inevitable loss and subsequent replacement of skeletal stores.6. The endogenous faecal loss of Ca was found to vary in direct relation to the food intake, and the significance of this finding to calculations of Ca requirements is discussed.

Endogenous faecal loss of phosphorus in growing lambs and the calculation of phosphorus requirements

1985 ◽  
Vol 105 (1) ◽  
pp. 67-72 ◽  
Author(s):  
G. D. Braithwaite
Keyword(s):  
Research Council ◽  
Agricultural Research ◽  
Constant Level ◽  
Direct Relation ◽  
Agricultural Research Council ◽  
Phosphorus Requirements ◽  
P Absorption

SUMMARYThe endogenous faecal loss of P has been investigated in growing lambs given diets either grossly deficient, moderately deficient or just adequate in P. This loss was found to increase in direct relation to the increased P intake, in spite of the high P requirements of the deficient animals, which suggests that some increased loss with increased P intake is inevitable. Results throw doubt on the validity of the assumption made by the Agricultural Research Council (1980) in their calculations of P requirements, that the endogenous faecal loss of P is maintained at a constant level equal to that which occurs at zero P intake, until requirements are met.Even on the diet which was, according to Agricultural Research Council (1980) recommendations, just adequate in P, lambs were unable to retain the expected amount of P commensurate with their growth. This inability to retain P was not due to a failure of P absorption, since the efficiency of absorption from this diet was higher than the value used by the Agricultural Research Council (1980) in their calculations. Rather, it must have been due to an inevitable endogenous faecal loss of P that was considerably higher than the value assumed by the Agricultural Research Council (1980).It is suggested that in future the value of endogenous faecal loss used in calculations of P requirements is the minimum one that allows a particular requirement to be achieved.

Changes in phosphorus metabolism of sheep in response to the increased demands for P associated with an intravenous infusion of calcium

1984 ◽  
Vol 102 (1) ◽  
pp. 135-139 ◽  
Author(s):  
G. D. Braithwaite
Keyword(s):  
Intravenous Infusion ◽  
Calcium Metabolism ◽  
Research Council ◽  
Agricultural Research ◽  
Close Association ◽  
High Rate ◽  
Phosphorus Metabolism ◽  
Agricultural Research Council ◽  
P Absorption ◽  
P Retention

SummaryThe effect on phosphorus and calcium metabolism of a high rate of Ca infused directly into the blood of 10-month-old sheep, already receiving an adequate Ca and P intake, has been studied by a combination of balance and radioisotope techniques. Ca retention was significantly increased during the infusion and most of the extra Ca was retained in bone. Urinary Ca excretion also showed a small but significant increase and the efficiency of Ca absorption a small but significant decrease. Because of the close association of Ca and P in bone, the increased skeletal retention of Ca resulted in an increased skeletal P retention and hence an increased demand for P. This increased P demand was met partly by a decrease in the rate of endogenous faecal loss of P and partly by an increase in the rate and efficiency of P absorption. Because the increase in P demand was relatively small, it was not possible to decide whether the endogenous faecal loss of P can be reduced in response to increased demands to the level found at zero P intake as suggested by the Agricultural Research Council (1980) or whether higher losses at normal P intakes are inevitable.

Effect of reduction in phosphorus intake on salivary phosphorus secretion and on duodenal digesta and dry-matter flow in sheep

1988 ◽  
Vol 110 (2) ◽  
pp. 411-413 ◽  
Author(s):  
D. Scott ◽  
W. Buchan
Keyword(s):  
Dry Matter ◽  
Research Council ◽  
Agricultural Research ◽  
Agricultural Research Council ◽  
Phosphorus Requirements ◽  
Phosphorus Intake ◽  
Matter Flow

The Agricultural Research Council (1980) has recently published revised estimates of the phosphorus requirements for ruminants. These new estimates are considerably lower than those formerly recommended (Agricultural Research Council, 1965) and some concern has been expressed as to whether or not they are adequate (Cooke, 1982; Todd, 1983).

Mineral and vitamin supplementation of diets for growing pigs. 3. Salt, calcium and phosphorus, and trace mineral supplements in a wheat/soybean meal diet

1978 ◽  
Vol 18 (95) ◽  
pp. 781
Author(s):  
EB Greer ◽  
CE Lewis
Keyword(s):  
Soybean Meal ◽  
Research Council ◽  
Agricultural Research ◽  
Bone Development ◽  
Growing Pigs ◽  
Vitamin Supplementation ◽  
Feed Conversion ◽  
Broken Bones ◽  
Agricultural Research Council ◽  
Calcium And Phosphorus

A 2 x 2 x 3 x 3 factorial experiment with 72 growing pigs examined the effect of adding salt, calcium and phosphorus (Ca + P) and trace minerals (TM-manganese, zinc, iron and copper) to a wheat/soybean meal diet. Gilts and barrows were individually fed at restricted intakes from 20 kg liveweight. Pigs required both salt and Ca + P to reach slaughter at 73 kg. Without these minerals they stopped growing; lameness and broken bones were also common. All pigs fed salt plus the higher level of Ca + P (0.84 and 0.57 per cent, respectively) completed the experiment but only half those fed salt plus the lower level (0.42 and 0.29 per cent Ca + P, respectively) did so. There was a response to salt within three weeks. In the first four weeks, 0.125 per cent added salt improved growth by 26.5 per cent and feed conversion ratio by 21 per cent. The results indicated that growing pigs require less sodium than currently estimated (Agricultural Research Council). A response to both levels of supplementary Ca + P was seen after about seven weeks with salt and nine weeks without salt. In the first eight weeks of the experiment there were no differences in performance between the two levels of added Ca + P when salt was also used. Between 8 and 12 weeks, pigs fed the higher level grew 17 per cent faster. Although 0.84 + 0.57 per cent Ca + P increased rib Ca and P levels, foot and joint abnormalities showed that these levels were insufficient for normal bone development. This suggests that the Agricultural Research Council estimates of Ca and P requirements for restrictively fed growing pigs are low. TM supplementation did not affect performance when both salt and Ca + P were added to the diet.

The phosphorus requirements for growth and maintenance of sheep

1982 ◽  
Vol 99 (2) ◽  
pp. 311-317 ◽  
Author(s):  
A. C. Field ◽  
R. L. Coop ◽  
R. A. Dingwall ◽  
C. S. Munro
Keyword(s):  
Feed Intake ◽  
Research Council ◽  
Agricultural Research ◽  
Live Weight ◽  
Faecal Excretion ◽  
Agricultural Research Council ◽  
Pelleted Diet ◽  
Phosphorus Requirements ◽  
Female Sheep ◽  
Balance Trials

SUMMARYPhosphorus requirements for maintenance and growth were assessed by giving to growing lambs and non-pregnant ewes diets low in P and to growing lambs a diet containing the quantity of P recommended by the Agricultural Research Council (1980).Seven 14-week-old lambs were given ad libitum a pelleted diet containing 1·88 (LP) or 2·75 (NP) g P/kg D. M. for 13 weeks. There was no effect of P intake on feed intake or growth during the first 8 weeks when the P intake of the LP groups was 1·07 of Agricultural Research Council (1980) requirements. During the last 5 weeks the P intake of the LP group was only 0·87 of Agricultural Research Council (1980) requirements and growth and feed intake were higher in the male but not female lambs in the NP group. From the 3rd week the plasma concentration of P was significantly lower (P <0·001) in the LP group. Mineralization of selected bones was less in the LP group.After 14 weeks on the diet, balance trials with 32 P were carried out on the lambs from each dietary group. P intakes ranged from 1 to 3 g/day. An additional balance trial was undertaken with eight 2-year-old female sheep consuming a hay diet (1·5 g P/day).The endogenous faecal excretion of P by the growing lambs on the LP diet and ewes was 12·2 ± 0·8 and 12·7 ± 1·00 mg/kg live weight/day respectively, very close to the value (12 mg/kg live weight/day) adopted by the Agricultural Research Council (1980). The absorbability of the P in the concentrate and hay diets was 0.71 ±0·267 and 0·74 ± 0·0218 respectively, the former agreeing with and the latter higher than the corresponding value for Agricultural Research Council (1980).

Some observations on endogenous loss of calcium in the sheep

1969 ◽  
Vol 73 (3) ◽  
pp. 507-509 ◽  
Author(s):  
A. C. Field ◽  
N. F. Suttle
Keyword(s):  
Research Council ◽  
Agricultural Research ◽  
Live Weight ◽  
Adult Sheep ◽  
Agricultural Research Council ◽  
Calcium And Phosphorus

SummaryEstimates of endogenous loss of calcium have been obtained from balance studies with growing lambs and adult sheep given diets containing deficient and adequate amounts of calcium and phosphorus. The values were generally lower than those obtained for sheep by methods employing radioactive calcium and it was concluded that the endogenous loss by sheep is considerably less than the figure used by the Agricultural Research Council (1965) and is probably of the same order as that of cattle (16 mg/day kg live weight).

XIV.—Rowett Research Institute

1951 ◽  
Vol 64 (3) ◽  
pp. 257-276
Author(s):  
D. P. Cuthbertson
Keyword(s):  
Royal Society ◽  
Research Council ◽  
Medical Research Council ◽  
Agricultural Research ◽  
Research Work ◽  
Animal Nutrition ◽  
College Of Agriculture ◽  
The North ◽  
Agricultural Research Council ◽  
The University

The Rowett Institute for research on animal nutrition had its origin under a scheme for promoting scientific research in agriculture adopted by the Development Commission in 1911.The Governing Body, which originally consisted of an equal number of members appointed by the Court of the University of Aberdeen and the Governors of the North of Scotland College of Agriculture, was constituted in 1913. Within recent years it has been expanded to include persons nominated by the Secretary of State for Scotland, the Royal Society, the Royal Society of Edinburgh, the Agricultural Research Council, and the Medical Research Council. Research work was begun in temporary accommodation in Marischal College in 1914, under the direction of Dr John Boyd Orr—now Lord Boyd-Orr—who continued as Director until his retirement in 1945.

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