The effect of the replacement of concentrates by roots on the intake and production of dairy cows

Abstract

SummaryTo investigate the effect of replacing part of the concentrates by roots, a 16-week winter-feeding experiment was made using twelve Ayrshire cows. All the cows received 8 lb of hay per day and enough grass silage for a measurable residue to be left at each feed. Two rations were supplemented with 45 lb of fodder-beet per day but the other two contained no roots. At each level of root feeding, concentrates were fed at either 3·50 or 1·75 lb per 10 lb of milk.All the fodder-beet was eaten (8·4 lb dry matter) and, as this caused a reduction in the intake of silage dry matter of only 3·4 lb per day, there was a net increase in drymatter intake. The level of concentrate feeding had little effect on the intake of the other feeds. Rations which included roots contained significantly less crude fibre than rations without roots.The mean daily milk yields for the treatments with the low and high concentrate levels were 29·5 and 33·9 lb, respectively, without roots and 31·8 and 35·8 lb with roots. The fat percentages of the milk were similar on all four treatments whereas the solids-not-fat (S.N.F.) increased significantly from 8·42% on the treatment without roots and low concentrates to 8·64% on the treatment with roots and high concentrates. The response per 1 lb of extra S.E. was 1·0 lb milk and 0·02% S.N.F. between the low and high concentrate treatments and 0·7 lb milk and 0·05% S.N.F. between the two root treatments. The analysis of milk from individual quarters of all the cows during each period showed the continuous presence of some subclinical mastitis. It was estimated that this lowered the general level of S.N.F. percentage by 0·2% but did not bias the results from any one feeding treatment. For milk from healthy quarters only, the response to 1 lb extra S.E. from concentrates was 0·03% S.N.F. and from beet it was 0·08% S.N.F.

The effect of concentrate feed level on the response of lactating dairy cows to a constant proportion of fodder beet inclusion in a grass silage‐based diet

“…The milk yield response to concentrate supplementation was considerable across all levels of concentrate, with the linear response being equivalent to 0·92 kg milk kg −1 concentrate DM. However, although positive milk yield responses to the inclusion of fodder beet were observed in a number of early studies (Castle et al ., 1961; 1963), and indeed more recently (Phipps et al ., 1995), milk yield was unaffected by the inclusion of fodder beet in the current study, in common with the results of a series of studies undertaken in Scotland (Roberts, 1987; Sabri and Roberts, 1988; Fisher et al ., 1994). Although the lack of a yield response, despite a large increase in ME intake, is surprising, the trend towards a higher milk yield, combined with the higher milk energy contents associated with rations containing fodder beet, resulted in a small but significant increase ( P < 0·01) in milk energy output (77·8 vs. 81·3 MJ d −1 , across all concentrate levels).…”

“…In agreement with the findings of many other studies (Castle et al ., 1961; 1963; Sabri and Roberts, 1988; Fisher et al ., 1994), total DM intakes were increased by the inclusion of fodder beet in the diet. However, this increase in DM intake declined with increasing concentrate level, a reflection of the decreasing proportion of fodder beet in the overall diet.…”

“…However, although the use of maize silage and whole‐crop silage in dairy cow rations has been examined extensively in recent years, fodder beet has received much less attention. The limited work undertaken has indicated that fodder beet, when used as an additional dietary component, normally increases ME intakes, although milk output responses have been variable (Castle et al ., 1963; Roberts, 1987; Sabri and Roberts, 1988; Fisher et al ., 1994). In addition, most studies have examined the response to fodder beet inclusion at a single modest level of concentrate supplementation, and have not examined the response at high levels of supplementation, or identified whether there is an interaction between dietary fodder beet inclusion and level of concentrate supplementation.…”

The effects of feeding fodder beet with two levels of concentrate allocation to dairy cattle

“…Feeding fodder beet to dairy cows has been shown to increase total DM intake and milk yield (Castle et al, 1961;1963;Roberts, 1987). De Brabander et al (1976;1981) found that fodder beet decreased the intake of basal forage.…”

Complémentation d'un ensilage d'herbe par des pulpes de betteraves : effet sur les quantités ingérées, les activités alimentaires et méryciques, et la digestion chez les génisses

“…De plus, la distribution de pulpes sèches a augmenté le flux duodénal de tous les acides aminés, cette augmentation étant significative excepté pour la sérine, la glycine, la cystéine et la méthionine (fig 1 ). (Castle et al, 1963;Castle, 1972) et les pulpes surpressées ensilées (Dulphy et al, 1978;De Brabander et al, 1980) …”