Influence of Source of Nitrogen on Performance and Plasma Amino Acid Patterns of Lambs

Theurer, Brent; Woods, Walter; Poley, Gerald E.

doi:10.2527/jas1968.2741059x

Cited by 12 publications

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“…1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 2 4 The urea content of the milk was significantly depressed by all treatments, but there were no marked differences in total NPN. Milk-clotting time was significantly longer in all test groups, in agreement with the findings of Todorov et al (1969).…”

Section: Resultssupporting

confidence: 90%

“…1; no general trend is apparent. However, when the amino acids are divided into essential and non-essential, the grouped values show opposing trends (Table 5), in agreement with the findings of Theurer, Woods & Poley (1968).…”

Section: Lys His a R G Asp T H R Ser G L U Pro G L Y A L A Cys V A L supporting

confidence: 89%

“…Sauer (1938) also found this when feeding 32 g urea/head daily to wether lambs. Trials conducted in Ohio by Woods & Tolman (1966) demonstrated that pelleting of urea with lucerne hay may allow 40 % N to be replaced in the ration of highproducing dairy cows.Results from experiments carried out in Nebraska by Conrad & Hibbs (1966) showed that dairy cows used urea to advantage when it replaced 66-5 % of dietary N. These authors considered that in such a case the amount of mineral supplementation should be increased several fold. …”

mentioning

confidence: 98%

mentioning

confidence: 98%

“…A number of authors (Virtanen, 1966(Virtanen, , 1967Todorov et al 1969) have studied the influence of rations in which NPN substances, mostly urea and ammonium salts, were the only N source.…”

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Effect of 75% replacement of dietary N by urea and ammonium sulphate on the composition and properties of sheep's milk

Tanev

1973

Journal of Dairy Research

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A 23-week trial was conducted using 4 groups each of 6 ewes to study the effects on milk yield and composition of substituting non-protein nitrogen (NPN) for 75 % of the dietary nitrogen. The control group received a winter ration which included silage followed by a summer ration containing lucerne. The test groups received substitutes of urea, ammonium sulphate, or urea + (NH 4 ) 2 SO 4 . The milk yield of the test groups was lower (P < 0-01) than that of the control group. Depression of the fat content of the milk reached statistical significance (P < 0-01) in the groups receiving (NH 4 ) 2 SO 4 and urea + (NH 4 ) 2 SO 4 . In comparison with the control group, the protein content of the milk was greater in the group receiving urea and smaller in the other 2 test groups. The milks of the test groups had lower amounts of essential amino acids in the free state and higher amounts of non-essential amino acids than did the control milk. Milk-clotting time was increased in the test groups; the increase was greatest (P < 0-01) for the group receiving (NH 4 ) 2 SO 4 and least (P < 0-05) for that receiving urea.The desirability of increasing the percentage of ruminant dietary protein which can be replaced by non-protein nitrogen (NPN) has prompted a large number of investigations in this area. A number of authors (Virtanen, 1966(Virtanen, , 1967Todorov et al. 1969) have studied the influence of rations in which NPN substances, mostly urea and ammonium salts, were the only N source.Rations in which NPN replaced over 50 % of the required N were fed to animals by various workers. Thus, Hale (1955) reported that lambs fed rations in which urea replaced 92 % of the needed N showed good weight gain, and Johnson et al. (1942) found no adverse influence of 65 % urea. Sauer (1938) also found this when feeding 32 g urea/head daily to wether lambs. Trials conducted in Ohio by Woods & Tolman (1966) demonstrated that pelleting of urea with lucerne hay may allow 40 % N to be replaced in the ration of highproducing dairy cows.Results from experiments carried out in Nebraska by Conrad & Hibbs (1966) showed that dairy cows used urea to advantage when it replaced 66-5 % of dietary N. These authors considered that in such a case the amount of mineral supplementation should be increased several fold.

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Section: Resultssupporting

confidence: 90%

Section: Lys His a R G Asp T H R Ser G L U Pro G L Y A L A Cys V A L supporting

confidence: 89%

mentioning

confidence: 98%

mentioning

confidence: 98%

mentioning

confidence: 99%

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