Changes

SARA can impact production parameters. Milk yield is lowered, although on farms where subacute rumenal acidosis is an ongoing, chronic problem, this may not be recognised. Milk butterfat levels are also reduced, which may be due to two factors. Firstly, milk fat is produced from acetate and butyrate, which in turn are produced from fibre in the diet. Dietary fibre is often reduced in SARA

SARA can impact production parameters. Milk yield is lowered, although on farms where subacute rumenal acidosis is an ongoing, chronic problem, this may not be recognised. Milk butterfat levels are also reduced, which may be due to two factors. Firstly, milk fat is produced from acetate and butyrate, which in turn are produced from fibre in the diet. Dietary fibre is often reduced in SARA

and so butterfat levels are, in turn, decreased. Alternatively, the changes in the rumen environment in subacute rumenal acidosis could interfere with the biohydrogenation of fatty acids, and milk fat could be reduced in this way. Reproductive performance is also poor; bulling behaviour and the duration of oestrus are negatively affected, and subobtimal nutrition reduces conception rates.

and so butterfat levels are, in turn, decreased. Alternatively, the changes in the rumen environment in subacute rumenal acidosis could interfere with the biohydrogenation of fatty acids. Reproductive performance is also poor; bulling behaviour and the duration of oestrus are negatively affected, and subobtimal nutrition reduces conception rates.

The incidence of a number of diseases is increased by concurrent subacute rumenal acidosis. For example, cases clinical acetonaemia and left displacement of the abomasum occur more frequently with herds where SARA is an issue. Loose faeces gives contamination of the environment and the udder, and in combination with the detrimental effects of SARA on the immune system, this can give a rise in levels of environmental mastitis. Subacute rumenal acidosis also predisposis to coriosis (the bovine equivalent of laminitis), so affect herds may have a high prevalence of foot lameness, with solar abscesses and ulcers frequently seen. Knowledge of the mechanism for induction of coriosis by SARA is limited.

The incidence of a number of diseases is increased by concurrent subacute rumenal acidosis. For example, cases of clinical acetonaemia and left displacement of the abomasum occur more frequently with herds where SARA is an issue. Loose faeces gives contamination of the environment and the udder, and in combination with the detrimental effects of SARA on the immune system, this can give a rise in levels of environmental mastitis. Subacute rumenal acidosis also predisposes to coriosis (the bovine equivalent of laminitis), so affected herds may have a high prevalence of foot lameness, with solar abscesses and ulcers frequently seen. Knowledge of the mechanism for induction of coriosis by SARA is limited.

When investigating a case of potential subacute rumenal acidosis, the cows should be closely examined. The condition score of animals in early lactation should be recorded, as well as rumen fill and the percentage of cows ruminating at any time. This latter value should be at least 60% in a normal herd. A cow comfort quotient can be calculated by dividing the number of cows lying correctly in cubicles by the total number of cows in the cubicles. This figure should be in the region of 80-90%. The cows should also be examined for cleanliness, and the consistency of their faeces scored. The production and records should be viewed and interpreted and the overall appearance and vigour of the animals appreciated.

When investigating a case of potential subacute rumenal acidosis, the cows should be closely examined. The condition score of animals in early lactation should be recorded, as well as rumen fill and the percentage of cows ruminating at any time. This latter value should be at least 60% in a normal herd. A cow comfort quotient can be calculated by dividing the number of cows lying correctly in cubicles by the total number of cows in the cubicles. This figure should be in the region of 80-90%. The cows should also be examined for cleanliness, and the consistency of their faeces scored. The production and records should be viewed and interpreted and the overall appearance and vigour of the animals appreciated.