The effect of clover-rich diets on cows in mid lactation: production, behaviour and nutrient use

Abstract

Mixed species pastures typically have insufficient clover to capture its high nutritional value as extra milk production. This paper reports interim results of a study investigating novel methods of presenting white-cloverrich diets to cows. Cows were offered continuous, free access to grass and clover growing separately side-byside in the same paddock (G/C), or grass-only at night between the afternoon and morning milking and cloveronly during the day between the morning and afternoon milking (GnCd). These treatments were compared against controls of grass-only pasture (Grass) and mixed grassclover pasture (Mix; 92% grass, 8% clover). Cows offered G/C or GnCd produced 2.0 and 1.9 kg MS/cow/ day, respectively, compared with 1.5 kg MS/cow/day for cows grazing Grass and Mix. The AM and PM milkfat of cows grazing G/C contained high levels of skatole, an indicator of protein digestion and metabolism, compared with Grass and Mix. For GnCd, levels were high only in the PM milk and low in the AM milk following the grass-only diet at night. The GnCd cows grazed proportionately more during the 'day' and less at 'night' than the G/C cows. Manipulating the spatial and temporal allocation of grass and white clover to align nutrient allocation with the nutritional and behavioural needs of the cow boosts MS production, but there is scope to improve the efficiency of protein utilisation in the rumen. Keywords: grass, white clover, milk production, grazing behaviour, skatole