Intragastric infusion of nutrients in cattle

MacLeod, N. A.; Corrigall, William A.; Stirton, R. A.; Ørskov, E. R.

doi:10.1079/bjn19820066

Cited by 50 publications

(39 citation statements)

References 6 publications

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“…into the abomasum, inserted 5-6 weeks after calving, using a procedure similar to that described by MacLeod et al (1982) except that general anaesthesia was used. The animals were housed individually in metabolism stalls and milked each day at 06.00 and 16.00 hours.…”

Section: Animals and Managementmentioning

confidence: 99%

The effects of abomasal infusions of casein or soya-bean-protein isolate on the milk production of dairy cows in mid-lactation

Choung

Chamberlain

1993

Br J Nutr

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The effects of abomasal infusion of casein or soya-bean-protein isolate (SPI) on milk production were investigated in four Friesian cows in mid-lactation receiving a basal diet of grass silage and barley which supplied energy and protein considerably in excess of requirements for milk production by conventional rationing standards. Three levels of infusion were used for each protein source, the corresponding doses being isonitrogenous for each of the proteins: 100,220 and 330 g/d for casein and 115,230 and 345 g/d for SPI. Casein produced much greater effects on the yield of milk and milk constituents than did SPI. On the highest dose of casein, milk yield was increased by 3.5 kg/d, fat output by 15% and protein output by 36%; corresponding values for the highest dose of SPI were 1.6 kg/d, 12% and 13% respectively. Increases in the yield of milk-protein were linear for casein but for SPI there was no increase beyond the first level of infusion. It was calculated that casein infusion had a marked effect on the utilization of energy: the increases in milk production could be explained either by a channelling of an extra 12 MJ metabolizable energy (ME)/d away from body tissue synthesis and into milk synthesis or by an increase in the efficiency of utilization of ME for lactation from 0.50 on the basal diet to 0.58; the measurements made did not allow the two mechanisms to be clearly differentiated. There are a number of reports of increased milk production of dairy cows in response to the infusion of casein into the abomasum (see Clark, 1975; 0rskov et al. 1977;Rulquin, 1982;Konig et al. 1984;Whitelaw et al. 1986). Responses were greatest when energy intake in early lactation was restricted to ensure some dependence on body energy stores (0rskov et al. 1977;Whitelaw et al. 1986). Abomasal protein infusionsTwo questions are raised : (1) If casein infusion can stimulate mobilization of body fat when energy intake is restricted in early lactation, can it influence the pattern of energy use in cows in mid-lactation consuming energy and protein in excess of their requirements for milk production? (2) how do the responses elicited by casein relate to those obtained with a protein more representative of those used in practice?The experiment reported here compared the effects of abomasal infusions of casein and of soya-bean protein. Both proteins were infused at three dose levels in cows in midlactation receiving a diet containing a fixed amount of barley and high-quality grass silage offered ad lib.

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Section: Animals and Managementmentioning

confidence: 99%

The effects of abomasal infusions of casein or soya-bean-protein isolate on the milk production of dairy cows in mid-lactation

Choung

Chamberlain

1993

Br J Nutr

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“…A standard volatile fatty acid (VFA) solution containing acetic, propionic and n-butyric acids in the molar proportions 0 65, 0-25 and 010 respectively was infused into the rumen, together with the major minerals (MacLeod, Corrigall, Stirton & 0rskov, 1982), in a total daily volume of 34 1. The appropriate quantity of buffer solution was infused separately to the rumen in a total daily volume of 64 1.…”

Section: Animals and Managementmentioning

confidence: 99%

Urea degradation in sheep nourished by intragastric infusion: effects of level and nature of energy inputs

Whitelaw¹,

Milne²

1991

Experimental Physiology

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SUMMARYFour female sheep nourished wholly by infusions of volatile fatty acids (VFA), buffer and minerals to the rumen and casein to the abomasum were given in addition infusions of supplementary energy calculated to increase the energy input to the rumen by 30 %. The design was a Latin square and the supplements given were (a) nil, (b) a standard VFA mixture similar to the basal infusion, (c) butyric acid alone and (d) glucose. Measurements were made of nitrogen retention and rumen fermentation characteristics and the kinetics of urea metabolism were measured over 24 h by means of a single injection of ['4C]urea. An active microbial fermentation was established in the rumen in response to the infusion of glucose and estimates of microbial protein synthesis derived from urinary purine excretion agreed well with those calculated from stoichiometric principles. The presence of a microbial population in the rumen resulted in a decrease in urinary urea excretion and reductions in plasma urea concentration, urea pool size and rumen ammonia (NH3) concentration. Infusion of the mixed VFA or butyric acid supplements had no effect on these indices of urea metabolism. Measurements of urea irreversible loss rate showed high variability and the mean values did not differ significantly between the four treatments. Urea degradation in the gastrointestinal tract was also highly variable but increased, on average, by 2 4 g day-1 on the high-energy treatments. Examination of regression relationships between these variables also indicated a difference between the glucose treatment and the others in the metabolic fate of the NH3 derived from urea hydrolysis. It is concluded that urea degradation increased in response to additions of energy but did not differ according to the nature of the supplements supplied. In the glucose-supplemented group, the NH3 arising from degraded urea was incorporated into microbial protein and so removed from the urea-NH3 cycle; when additions of mixed VFA or butyric acid were given, the NH3 arising in hydrolysis appeared simply to be reabsorbed as NH3 and to contribute anew to urea formation.

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“…The volatile fatty acid (VFA), buffer, casein and mineral solutions were prepared as described by MacLeod, Corrigall, Stirton & 0rskov (1982) and were infused continuously over 24 h. The VFA solutions contained acetic, propionic and n-butyric acids in the molar proportions 0 65, 0 25 and 0O10 respectively. The water-soluble vitamins were incorporated in the casein infusate and trace minerals were given once daily by injection into the abomasum.…”

Section: Introductionmentioning

confidence: 99%

Urea metabolism in sheep given conventional feeds or nourished by intragastric infusion

Whitelaw¹,

Milne²,

Er³

et al. 1990

Experimental Physiology

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SUMMARYA comparison has been made of the kinetics of urea metabolism in sheep given conventional feeds or maintained wholly by intragastric infusions of volatile fatty acids, buffer, mineral and casein solutions. Daily nitrogen supply was 132 g/day in 'fed' sheep and 6-0 g/day in 'infusion' sheep. On each feeding system measurements were made at the basal (maintenance) level of intake and when the basal level was supplemented with infusions of urea into the abomasum (125 mmol/day) or into the rumen (300 mmol/day). Additional measurements were made when ammonium carbonate (100 mmol/day) was infused into the rumen, when cassava (150 g/day) was added to the diet of 'fed' sheep or when the input of casein to 'infusion' sheep was reduced by half. Urea kinetics were measured by means of a single intravenous injection of ['4C]urea. Urea irreversible loss rate, urea pool size, urinary urea excretion, plasma urea concentrations and rumen ammonia concentrations were all significantly higher in sheep given conventional feeds than in those nourished by infusion but urea degradation in the gastrointestinal tract did not differ between the two methods of feeding. Regression analysis indicated only minor differences between the two feeding systems in the relationships between the various indices of urea metabolism. It is concluded that most of these findings can be attributed to differences in the quantity and nature of the nitrogen supplied in the basal diets and that the sheep nourished by infusion would be a suitable model for the study of factors involved in the control of urea recycling.

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Intragastric infusion of nutrients in cattle

Cited by 50 publications

References 6 publications

The effects of abomasal infusions of casein or soya-bean-protein isolate on the milk production of dairy cows in mid-lactation

The effects of abomasal infusions of casein or soya-bean-protein isolate on the milk production of dairy cows in mid-lactation

Urea degradation in sheep nourished by intragastric infusion: effects of level and nature of energy inputs

Urea metabolism in sheep given conventional feeds or nourished by intragastric infusion

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