The effect of abomasal infusion of casein on acetate, palmitate and glucose kinetics in cows during early lactation

Abstract

1. Four mature Friesian cows were used in a Latin square design experiment to measure the effects of abomasal casein infusion on milk production and the kinetics of glucose, acetate and palmitate in jugular venous blood.2. The basal ration contained 11 0 g crude protein/kg dry matter and was offered at the rate of 4 kg hay, 3 kg alkali-treated straw cubes plus 9 kg concentrates/d. Treatments were infusion of casein into the abomasum at the rate of 0, 240 or 460 g/d. The experiment started 1 week post partum. Experimental periods lasted 21 d.3. [6-SH]glucose, [9, 10-3H]palmitate and [U-"C]acetate were continuously infused into one jugular vein for measurements of whole-body flux rates.4. The yield of milk protein was increased significantly (P < 0.05) by the first increment of casein infusion, with no further increases.5. Casein infusion had no effect on blood concentrations of glucose, acetate, palmitate or growth hormone.Mean flux rate of glucose increased with each increment of casein. The effect at 460 g/d was higher (P < 0.1) than with no infusion. Flux rates of palmitate and acetate were increased (P < 0.1) by the first increment of casein.The proportion of blood bicarbonate derived from acetate increased (P -= 0.05) with the first increment of casein.6. Protein status of cows early in lactation influences the dynamics of glucose and fatty acid metabolism.

Whole body glucose turnover in growing and non-productive adult ruminants: meta-analysis and review

“…The dietary protein level may also influence the dynamics of glucose metabolism as shown in lactating cows [62]. Unfortunately, the available set of literature data collected for the present meta-analysis in growing and adult non-pregnant non-lactating ruminants was not sufficiently informative on the dietary protein contents to test its influence on glucose turnover.…”

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

“…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).…”

“…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).…”

Organic dairy production based on rapeseed, rapeseed cake or cereals as supplement to silagead libitum

“…That the milk fat content was not affected may be due to a positive effect of the frequent allocation of barley (Ørskov, 1999). According to Kö nig et al (1984) cows given low energy diets utilise additional protein supply as energy source and not for higher milk protein output.…”