Nitrogen and carbon flows between the caecum, blood and rumen in sheep given chopped lucerne (<i>Medicago sativa</i>) hay

Dixon, R. M.; Nolan, John

doi:10.1079/bjn19860039

Cited by 16 publications

(6 citation statements)

References 42 publications

(43 reference statements)

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“…Source of microbial N Several workers using intrarumen infusions of 15N-labelled ammonium salts to label rumen ammonia have suggested that considerable proportions (0.20-0.60) of rumen microbial N may be derived from sources other than ammonia (Kennedy & Milligan, 1978;Siddons et al 1 9 8 5~;Dixon & Nolan, 1986). These conclusions are based on the assumption that any N that is incorporated into the microbial N which has not equilibrated with the rumen ammonia pool, i.e.…”

Section: Eficiency Of Microbial Protein Synthesismentioning

confidence: 99%

Protein metabolism in the rumen of silage-fed steers: effect of fishmeal supplementation

et al. 1988

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1. Ryegrass (Lolium perenne cv. Cropper) silage was given to four Friesian steers (initial live weight (LW) 172 kg) alone or with a fishmeal supplement (150 g fresh weight/kg silage dry matter (DM)) in a balanced twoperiod change-over design. The dietary components were the same as those used in a recent experiment by Gill et a/. (1987). All diets were offered hourly at 24 g DM/kg LW.2. Fishmeal supplementation increased dietary nitrogen intake ( P < 0.01) and significantly increased the flow of total N (P <0.01), non-ammonia N (NAN) (P i 0.01) and amino acids ( P < 0.05) at the duodenum. 4. The efficiency of microbial protein synthesis was significantly increased from 30.8 g N/kg organic matter apparently digested in the rumen (OMADR) to 54.3 g N/kg OMADR by fishmeal supplementation ( P < 001).However, this indicates that relatively high efficiencies can be achieved with unsupplemented high quality silage supplied continuously. Rumen degradable N (RDN) supply was significantly increased by fishmeal supplementation (P < 0.05) but apparent efficiency of capture of RDN by rumen microbes was not significantly increased. 5. Attempts were made to investigate the source of N utilized by the microbes on the two diets by intrarumen infusions of ("NH,),SO, and ~-[4,5-~H]leucine but these were confounded by rumen-mixing problems. Findings obtained suggest that a lower proportion of microbial N may have been derived from rumen ammonia when the silage was supplemented with fishmeal but no differences in the extent of direct incorporation of leucine into microbial protein were observed. This could indicate an increase in microbial peptide uptake on the fishmealsupplemented diet. However, evidence was also obtained suggesting that the improvement in microbial protein synthetic efficiency with supplementary fishmeal was also due to the provision of a more continuous supply of nitrogenous substrates for microbial growth, as a result of hourly feeding.6. The results are related to the increased growth responses attained by fishmeal supplementation of this silage in the experiment of Gill et al. (1987).

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Section: Eficiency Of Microbial Protein Synthesismentioning

confidence: 99%

Protein metabolism in the rumen of silage-fed steers: effect of fishmeal supplementation

et al. 1988

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“…On For personal use only. Irreversible loss measurements of rumen bicarbonate were made using a procedure similar to that of Dixon and Nolan (1986). Calculations of duodenal and ileal flow were made using the double marker method after calculation of the reconstitution factor (Faichney 1975 The apparent digestibility of energy in the total tract was 80 and79% for the low-RDP diet and high-RDP diet, respectively (Table 3).…”

Section: Regimenmentioning

confidence: 99%

Effect of rumen degradable protein and lactation on nitrogen metabolism in dairy goats

Brun-Bellut¹,

Kelly²,

Mathison³

et al. 1991

Can. J. Anim. Sci.

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“…Urea that is excreted in the urine represents 25 to 60% of the endogenous urea production in ruminants (Obara and Shimbayashi, 1980;Huntington, 1989). Urine is the main medium through which urea is excreted; however, 65 to 76% of the urea-N that is transferred to the gastrointestinal tract enters the forestomachs (Huntington, 1989), which means that some N enters the post-ruminal portion of the gastrointestinal tract and may also appear in feces (Dixon and Nolan, 1986).…”

mentioning

confidence: 99%

Protein requirements for growth in male and female Saanen goats

et al. 2015

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-The objective of this study was to determine the protein requirements for the growth of intact male, female, and castrated male Saanen goats weighing 30 to 45 kg of body weight (BW) and to compare estimates of the protein requirements for maintenance (NP m ) by the comparative slaughter and nitrogen balance techniques. To determine the maintenance requirements, 55 goats were assigned in a split-plot design using a 3 × 3 factorial arrangement (three sexes and three dry matter intake (DMI) levels). A linear regression of retained N (as measured by the slaughter technique and estimated from the nitrogen balance) on N intake on a daily basis was used to calculate the net protein for maintenance. The net protein requirement for weight gain (NP g ) was obtained using 65 goats fed ad libitum in a completely randomized design. The first derivative of the allometric equation of protein content in the empty BW with respect to the empty BW yielded estimates of the NP g . According to the comparative slaughter technique, the estimated NP m was 1.46 g/kg of metabolic weight, which is 50% lower than the estimate from the nitrogen balance technique. When evaluating the variance of the error, the nitrogen balance also showed greater values, indicating less precision compared with that of the comparative slaughter technique. The daily NP g ranged from 155.7±10.9 to 153.4±13.5 g/kg of EBW gain for growing Saanen goats. The protein requirements (NP m and NP g ) of intact male, female, and castrated male Saanen goats are similar, from 30 to 45 kg BW, in accordance with current feeding systems. Moreover, the results of the present study indicate that the estimate of NP m using the comparative slaughter technique is more precise and lower than that using the N balance technique.

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Nitrogen and carbon flows between the caecum, blood and rumen in sheep given chopped lucerne (Medicago sativa) hay

Cited by 16 publications

References 42 publications

Protein metabolism in the rumen of silage-fed steers: effect of fishmeal supplementation

Protein metabolism in the rumen of silage-fed steers: effect of fishmeal supplementation

Effect of rumen degradable protein and lactation on nitrogen metabolism in dairy goats

Protein requirements for growth in male and female Saanen goats

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