Response of lactating goats to low phosphorus intake 2. Nitrogen transfer from rumen ammonia to rumen microbes and proportion of milk protein derived from microbial amino acids

Petri, Á.; Müschen, H.; Breves, Gerhard; Richter, Otto; Pfeffer, E.

doi:10.1017/s0021859600083209

Cited by 34 publications

(26 citation statements)

References 12 publications

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“…The slower reduction in feed intake due to P deficiency compared to that of N deficiency suggests either that the effect of the P deficiency operates through a different mechanism to that of N deficiency or that the reserves of P in steers delayed the onset of the intake reduction. It has been demonstrated with in vitro cultures that low rumen liquor P concentrations depress digestibility (Komisarczuk et al 1987) and in vivo ruminal microbial protein production in goats (Petri et al 1988). However in the present experiment, it is unlikely that the rumen fluid P concentrations would have been reduced to the same extent.…”

Section: Discussioncontrasting

confidence: 53%

Dietary nitrogen and phosphorus depletion in cattle and their effects on liveweight gain, blood metabolite concentrations and phosphorus kinetics

1996

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In a 15-week animal-house experiment, 24 steers were offered one of six diets based on molasses and ad libitum barley straw. Three levels of dietary nitrogen (N) and three levels of dietary phosphorus (P), in factorial combination, were formulated by the addition of urea, formaldehyde-treated wheat gluten and monosodium orthophosphate. Food intake, liveweight gain, plasma metabolites and P kinetics were measured under dietary regimens similar to those experienced by cattle grazing Australia's northern semi-arid rangelands.The adverse effect of the low dietary N on both liveweight change and feed intake was greater and more immediate than that of the dietary P deficiency. The reduction in feed intake due to the P deficiency approached that caused by the N deficiency after 10 weeks. Under conditions of adequate dietary N, there was a trend for the effects of P deficiency on liveweight gain to be exacerbated. Dietary N and P deficiency reduced the concentrations of plasma urea-N and inorganic P respectively. Dietary N deficiency had no effect on cortical rib bone thickness but P deficiency markedly decreased bone thickness. Faecal endogenous loss of P and P absorption efficiency ranged from 9 to 21 mg/kg LW and 063 to 0-82 respectively for P intakes from 6 to 41 mg/kg LW. Faecal endogenous losses were closely related to dry matter intake and plasma inorganic P together. Dietary N deficiency affected the efficiency of absorption of P.The results of this experiment indicate that cattle consuming diets containing low levels of N and P require supplementary N and P in combination to avoid severe depletion since an increase in N intake alone exacerbated the P deficiency. The results are also discussed in relation to the published findings regarding P metabolism and the implications for the calculation of P requirements.

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Section: Discussioncontrasting

confidence: 53%

Dietary nitrogen and phosphorus depletion in cattle and their effects on liveweight gain, blood metabolite concentrations and phosphorus kinetics

1996

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“…For example, P depletion has been associated with a reduction in microbial protein synthesis and organic matter digestibility in sheep and goats (Breves et al, 1985;Petri et al, 1988). However, dietary P level had no effect on the apparent digestibility of the DM, N, energy or ADF fractions of the rations offered in the current experiment, suggesting that rumen function was not impaired with the low P diet.…”

Section: Cow Fertilitymentioning

confidence: 99%

Effect of offering dairy cows diets differing in phosphorus concentration over four successive lactations: 2. Health, fertility, bone phosphorus reserves and nutrient utilisation

Ferris

McCoy

Patterson

et al. 2010

Animal

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This experiment examined the long-term effects of offering diets containing low levels of dietary phosphorus (P) on dairy cow health, fertility and bone composition, and the effect of dietary P level on nutrient utilisation. One hundred winter-calving Holstein-Friesian dairy cows were offered diets containing either 'high' or 'low' levels of dietary P over a 4-year period. Rations offered during the winter included grass silage, maize silage (70 : 30 dry matter (DM) basis, approximately) and concentrates (10.0 to 12.0 kg/cow per day). During the summer periods in years 1 and 2, half of the cows grazed both day and night, while the remaining cows grazed by day, and were housed by night and offered grass silage. During years 3 and 4, all cows grazed both day and night during the summer period. Concentrate feed levels during the summer periods were 3.0 to 4.0 kg/cow per day. Different dietary P levels were achieved by offering concentrates containing either high or low P levels during the winter period (approximately 7.0 or 4.4 g P/kg DM, respectively) and during the summer period (approximately 6.8 or 3.6 g P/kg DM, respectively). Total ration P levels averaged 4.9 and 3.6 g P/kg DM for the high and low P winter diets, respectively, and 4.2 and 3.6 g P/kg DM for the high and low P summer diets, respectively. A total of 95, 70, 50 and 22 cows completed each of lactations from 1 to 4, respectively. Neither the incidence of lameness or mastitis, or milk somatic cell count, were affected by dietary P level (P . 0.05), while none of the fertility parameters recorded in any of lactations from 1 to 4 was affected by the dietary P level (P . 0.05). Dietary P level had no effect on the specific gravity, ash or calcium content of rib cortical bone cores (n 5 78 cows), while the P content of cortical bone (g/kg fresh, g/kg DM and mg/ml fresh bone) was lower with cows offered low P diets (P , 0.05). Dietary P level had no significant effect on the digestibility of either the DM, nitrogen, energy or acid detergent fibre fraction of the diet (P . 0.05), while faecal P excretions were reduced by a mean of 27 g/cow per day with cows offered the low P diets during the winter period. The results of this study indicate that dietary P levels can be reduced to proportionately 0.8 (approximately) of current UK feeding standards (Agricultural and Food Research Council, 1991), with no detrimental effect on dairy cow health or fertility, while having only minor effects on bone composition.Keywords: dairy cows, phosphorus, fertility, bone, nutrient utilisation ImplicationsThis study examined the impact of offering reduced phosphorus diets over a 4-year period on cow fertility and bone phosphorus status. Within this long-term study, no detrimental effects on either parameter was observed when a diet containing approximately 20% less phosphorus than recommended within the current UK feeding standards was offered. Offering a low phosphorus diet significantly reduced the quantity of phosphorus excreted in faeces.

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“…Levels are also lower in lambs fed low phosphate diets (Corlett & Care, 1988;Corlett, Couch, Care & Sykes, 1990). This was taken to imply a reduction in bone formation rate (Corlett & Care, 1988) though it was unclear whether this was due to a lack of mineral per se or to a reduction in protein supply resulting from reduced rumen microbial protein synthesis; the latter effect has been reported in ruminants fed low P diets (Breves & Holler, 1983;Petri, Muschen, Breves, Richter & Pfeffer, 1988). To address this question we have measured plasma osteocalcin, mineral balance and microbial protein synthesis in lambs fed diets that were either low or adequate in P and, in addition, have monitored bone resorption rate using the excretion of pyridinoline and deoxypyridinoline in urine as markers (Robins, Black, Paterson, Reid, Duncan & Siebel, 1991).…”

Section: Introductionmentioning

confidence: 98%

Effects of low phosphate intake on bone and mineral metabolism and microbial protein synthesis in lambs

Scott¹,

Robins²,

Nicol³

et al. 1994

Experimental Physiology

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SUMMARYGrowing lambs were fed diets either low or adequate in phosphorus and their effects on Ca and P retention, bone formation and resorption and on ruminal microbial protein synthesis were measured. Plasma osteocalcin was used as an indicator of bone formation rate. Levels in plasma were lower in lambs fed the low P diet and were associated with a fall in plasma P concentration and reduced Ca and P retention. Low P intake had no effect on microbial protein synthesis or on bone resorption determined using urinary pyridinoline and deoxypyridinoline as markers. These results suggest that lack of mineral, rather than reduced ruminal microbial protein synthesis, is the main factor contributing to the reduction in bone formation rate seen in lambs fed low P diets.

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Response of lactating goats to low phosphorus intake 2. Nitrogen transfer from rumen ammonia to rumen microbes and proportion of milk protein derived from microbial amino acids

Cited by 34 publications

References 12 publications

Dietary nitrogen and phosphorus depletion in cattle and their effects on liveweight gain, blood metabolite concentrations and phosphorus kinetics

Dietary nitrogen and phosphorus depletion in cattle and their effects on liveweight gain, blood metabolite concentrations and phosphorus kinetics

Effect of offering dairy cows diets differing in phosphorus concentration over four successive lactations: 2. Health, fertility, bone phosphorus reserves and nutrient utilisation

Effects of low phosphate intake on bone and mineral metabolism and microbial protein synthesis in lambs

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