The effect on growth rate and on milk yield and composition of finely grinding the hay and cooking (flaking) the maize in mixed diets for growing and for milking heifers

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SUMMARYProcessed straw, both ground and ground–NaOH treated, has been compared with long straw in diets of straw and concentrates fed to yearling dairy heifers. Protein allowances were varied by the addition of fishmeal.Improved growth rate was consistently observed with those animals receiving fishmeal. When a fixed amount of barley straw was offered neither digestibility nor growth was affected by the form of the straw. With wheat straw grinding–NaOH treatment resulted in increased growth when fed in diets containing some long roughage. Voluntary intake of straw was additively increased by grinding and by treatment with 5% (w/w) NaOH. Ground-NaOH treatment of straw increased in vitro digestibility.

Section: Discussionsupporting

confidence: 65%

The effects of grinding, either with or without NaOH treatment, on the utilization of straw by yearling dairy cattle

Smith¹,

Broster²,

Broster³

et al. 1981

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“…They attributed a large part of the increase in rate of live-weight gain observed after these treatments of the foods to the changes in volatile fatty acid proportions. Balch, Broster, Rook & Tuck (1965) did not record an increase in live-weight gain of heifers as a result of similar preparations of the diet. Rook, Balch, Campling & Fisher (1963) infused dilute solutions of volatile fatty acids directly into the rumens of young dairy heifers and measured live-weight gains and nitrogen balances.…”

Section: Discussionmentioning

confidence: 84%

The effect of the addition of large amounts of cod-liver oil to the rations of yearling heifers on their rate of live-weight gain

Broster¹

1965

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1. Groups of twenty-four heifers were used in three experiments lasting 51–98 days. The effect on rate of live-weight gain of the addition of 150 ml. cod-liver oil to the daily ration was studied.2. The same treatments were used in each experiment: a basal diet consisting of hay and concentrates and two experimental diets consisting of the basal diet plus (a) 3 lb. concentrates, (b) 150 ml. (0·30 lb.) cod-liver oil. In one experiment flaked maize was used in the concentrates in place of crushed barley.

“…Increasing the concentrate: forage ratio will not evoke the same response if the concentrates are based on high-quality fibre. Earlier work (Balch et al 1955(Balch et al , 1965 also showed that the composition of the concentrates affected the response of milk fat concentration to reducing the proportion of forage in the diet but in those experiments it was the form of maize starch that was identified as being important which adds a further degree of complexity to the problem.…”

Section: Milk Production Responsesmentioning

confidence: 99%

A comparison of starchy and fibrous concentrates for milk production, energy utilization and hay intake by Friesian cows

Sutton¹,

Bines²,

Morant³

et al. 1987

102

Twenty-four Friesian cows were allocated to one of four diets for weeks 3-14 of lactation following 2 weeks on a common diet. The diets (kg air-dry feed/day) were 7-2 kg hay and 10-8 kg either starchy or fibrous concentrates (60S and 60F) or 3-5 kg hay and 14-0 kg either starchy or fibrous concentrates (80S and 80F). Rumen samples were taken by stomach tube in weeks 10 and 12 of lactation and the digestibility of the diets was measured with four cows per treatment during weeks 13 and 14. The digestibility of the same feeds was also measured in sheep at maintenance.The principal carbohydrate constituents of the concentrates were barley, wheat and cassava in the starchy concentrates and citrus pulp, sugar-beet pulp and wheat feed in the fibrous concentrates. The concentrates were designed to have similar concentrations of metabolizable energy (ME) and the diets were planned to provide similar intakes of digestible energy and crude protein.Milk yield and composition were very similar for treatments 60S and 60F. With the higher proportion of starchy concentrates (80S), milk yield was about 20% greater than on 60S, fat concentration fell severely but protein and lactose concentrations were unaffected. With the higher proportion of fibrous concentrates (80F), milk yield and the protein and lactose concentration were similar to values on 60F but fat concentration was lower, though not nearly so low as on 80S. Milk energy yield was reduced by the higher proportion of concentrates but was unaffected by type of carbohydrates. Live-weight changes were small.In both the sheep, consuming at maintenance, and the lactating cows consuming at about 3 times maintenance, digestibility of dry matter, organic matter and energy was higher with the higher concentrate diets but was unaffected by type of concentrate. The digestibility of fibre was greater with the fibrous concentrates but the effect of level of concentrate inclusion was inconsistent. Digestibility coefficients were consistently lower for the lactating cows than for the sheep.The proportion of acetic acid in the rumen volatile fatty acids in the cows was higher and the proportion of propionic acid was lower with the fibrous concentrates. The differences were much greater with the higher proportion of concentrates.During weeks 15-22 of lactation the cows were reallocated to concentrate treatments and given hay ad libitum. Hay intake was about 1 kg/day higher with the fibrous concentrates but the difference was not significant. Hay intake fell by about 0'6 kg/kg concentrate intake for both concentrate types. No significant differences in milk yield or composition were established, probably because of incomplete adaptation even after 8 weeks.