Protein Quantity and Quality for the Uk Dairy Cow

Broster, W. H.; Oldham, J. D.

doi:10.1016/b978-0-408-10804-1.50013-1

Cited by 12 publications

(10 citation statements)

References 67 publications

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“…There were no significant curvilinear relationships despite the fact that numerically maximum responses were generally recorded with the cows on treatment 3. The lack of eurvilinearity in the response to CP is consistent with the results of Gordon (1979) who also usod an ensiled material as the basal ration, but conflicts with the responses generally obtained when hay has been fed as the basal ration (Broster & Oldham, 1977).…”

Section: Discussionsupporting

confidence: 77%

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Protein studies on maize silage as a basal ration for dairy cows

Phipps¹,

Weller²,

Smith³

et al. 1981

J. Agric. Sci.

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In Expt 1 40 lactating British Friesians, 20 cows and 20 heifers, were used to study the effect of crude protein (CP) content of the whole ration on milk yield, milk composition and live-weight change when maize silage was fed as the basal ration. There were four treatments with five cows and five heifers on each. During lactation weeks 4-12 the cows on treatments 1, 2, 3 and 4 all received 7 kg maize silage dry matter (D.M.) plus 8 kg D.M./day of a concentrate containing either 14, 18, 22 or 24% CP, respectively; heifers received 1 kg/day less of both silage and concentrate. This produced whole-ration CP contents of 11-7, 13-9, 16-0 and 17-1%. In the subsequent lactation weeks 13-20 silage feeding was increased to 9 kg D.M./cow/day and concentrate feeding decreased to 5 kg D.M./cow/day. Heifers again received 1 kg/day less of both silage and concentrate. This decreased whole-ration CP contents to 10-5, 11-7, 12-9 and 13-4%.During lactation weeks 4-12 and 13-20, with the exception of milk fat content in weeks 13-20, there were significant linear effects of whole-ration CP content on milk yield, milk fat, protein, lactose and total solids. There were no significant curvilinear relationships. Thus, despite the fact that the highest numerical values were generally recorded for the animals on treatment 3, the results indicate that a whole-ration CP content of at least 17-1 and 13-4% are required in early and mid-lactation respectively.In Expt 2 the loss of D.M., acid-detergent fibre and nitrogen from maize silage suspended in nylon bags in the rumen was measured. Compared with feeding either a low or high protein supplement, losses were greater for silage fed alone. If it is accepted that nitrogen loss can be approximated to protein degradability, then the value for maize silage was between 0-6 and 0-7. Using the same technique in Expt 3, comparable nitrogen losses for fish meal, decorticated groundnut meal and soya-bean meal were 0-3, 0-9 and 0-9, respectively, after 24 h incubation.

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Section: Discussionsupporting

confidence: 77%

“…The literature on protein requirements for lactating dairy cows is extensive and has been reviewed by Broster & Oldham (1977). They illustrated the factors and complex interactions which influence protein requirements.…”

Section: Discussionmentioning

confidence: 99%

Protein studies on maize silage as a basal ration for dairy cows

Phipps¹,

Weller²,

Smith³

et al. 1981

J. Agric. Sci.

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“…The additional nitrogen secreted in the milk of the infused ewes relative to the control ewes represented 1% of that infused in week I and 23% in weeks 5 and 6.The only way the control ewes could maintain the same lactation performance as the infused ewes at peak lactation on a diet that fell short of supplying the amino acid absorption required for this level of production seems to be through greater mobilisation of labile body protein reserves. This hypothesis is supported by the calculations ofBroster & Oldham (1977), who showed that increments of digestible N given to dairy cows in early lactation produced only negligible increase in milk N output but markedly increased body tissue N retention.…”

Section: Milk Productionmentioning

confidence: 63%

Responses to abomasal infusions of casein plus methionine in lactating ewes fed fresh pasture

Barry¹

1980

New Zealand Journal of Agricultural Research

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Twin-bearing Romney ewes were fed fresh pasture of 80% organic matter digestibility (11.4 MJ ME per kg OM) and 3.5% N ad libitum for 6 weeks during early lactation. Eight of the 18 ewes were given a daily abomasal infusion of 95 g sodium caseinate and 2 g I-methionine. Voluntary pasture OM intake did not significantly differ between control and infused ewes. The infusions had no effect on milk secretion at peak lactation (week I), but the decline in net rates of protein and fat secretion as lactation progressed was less for infused than for control ewes. Wool production rates were low, and were unaffected by the infusion treatment. The quantity of amino acid N estimated to have been absorbed from the small intestine was respectively 85% and 110% of that required to sustain the levels of milk and wool production that were actually recorded in control and infused ewes. The absence of a difference in milk production between the two groups of ewes at peak lactation may have been due to greater mobilisation of body protein reserves by the control ewes. The higher plasma concentration of growth hormone observed in the infused ewes was probably implicated in their improved lactation persistency.

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“…A new approach to the estimation of protein requirements has been prepared by the Agricultural Research Council (see Roy et al 1977 for a notional outline). This is based on calculating the need in the rumen for degradable protein (RDP) to maximize the synthesis of microbial protein, and meeting any shortfall in protein supply to the intestine, relative to the host animal's requirements with undegraded protein (UDP) (0rskov, 1970, 1977Miller, 1973;, 1977Broster & Oldham, 1977).…”

Section: Introductionmentioning

confidence: 99%

A comparison of sources of supplementary nitrogen for young cattle receiving fibre-rich diets

Smith¹,

Broster²,

Hill³

1980

J. Agric. Sci.

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Fishmeal, soya-bean meal and urea were compared as nitrogen sources in diets rich in fibre for yearling cattle, using feeding trials and digestibility and nitrogen retention studies. All animals were individually fed. Diets supplemented with fishmeal supported the highest rates of daily live-weight gain and nitrogen retention. There was no response in dry-matter intake and digestibility from extra nitrogen, either from fishmeal or urea, when the crude protein of the diet was 8-5% or over, and a small response in digestibility when soya-bean meal was used.Molar proportions of VFA, rumen NH 3 -N concentrations and blood urea nitrogen concentrations were all affected by both amount and source of nitrogen supplementation. Multiple regression analysis showed the undegradable protein supply to be more critical with high than with low fibre diets.

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Protein Quantity and Quality for the Uk Dairy Cow

Cited by 12 publications

References 67 publications

Protein studies on maize silage as a basal ration for dairy cows

Protein studies on maize silage as a basal ration for dairy cows

Responses to abomasal infusions of casein plus methionine in lactating ewes fed fresh pasture

A comparison of sources of supplementary nitrogen for young cattle receiving fibre-rich diets

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