Reducing nitrogen surplus from dairy farms. Effects of feeding and management

Børsting, Christian Friis; Kristensen, Troels; Misciattelli, Lorenzo; Hvelplund, T.; Weisbjerg, M.R.

doi:10.1016/s0301-6226(03)00099-x

Cited by 67 publications

(44 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Theoretically, efficient recycling of endogenous urea-N will make it possible to maintain N supply for rumen microbes with less dietary N intake (Lapierre and Lobley, 2001). Nonetheless, under practical farming conditions dairy operations utilise only approximately 25% of the dietary N for milk, weight gain and foetal growth (Børsting et al, 2003). Numerous dietrelated factors can influence N efficiency, such as overfeeding with rumen degradable protein (Hristov et al, 2004), lack of synchronisation between ruminal carbohydrate and protein degradation (Casper et al, 1999), unbalanced composition of amino acids absorbed in the small intestine (Rulquin et al, 1993) and undersupply of -E-mail: nbk@agrsci.dk nutrients other than amino acids (Firkins et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Røjen

Lund

Kristensen

2008

Animal

View full text Add to dashboard Cite

Three ruminally cannulated and multicatheterised lactating dairy cows were used to investigate the effect of different supplement strategies to fresh clover grass on urea and short-chain fatty acid (SCFA) metabolism in a zero-grazing experiment with 24-h blood and ruminal samplings. Fresh clover grass was cut every morning and offered from 0800 to 1500 h. Maize silage was fed at 1530 h. The three treatments, arranged in a Latin square, differed by timing of feeding rolled barley and soya-bean hulls relative to fresh clover grass. All diets had the same overall composition. Treatments were soya-bean hulls fed at 0700 h and barley fed at 1530 h (SAM), barley fed at 0700 h and soya-bean hulls fed at 1530 h (BAM), and both soya-bean hulls and barley fed at 1530 h (SBPM). The grass had an unexpectedly low content of crude protein (12.7%) and the cows were severely undersupplied with rumen degradable protein. The treatment effects were numerically small; greater arterial ammonia concentration, net portal flux of ammonia and net hepatic flux of urea during part of the day were observed when no supplementary carbohydrate was fed before grass feeding. A marked diurnal variation in ruminal fermentation was observed and grass feeding increased ruminal concentrations of propionate and butyrate. The net portal fluxes of propionate, butyrate, isovalerate and valerate as well as the net hepatic uptake of propionate, butyrate, valerate and caproate increased after feeding at 0700 h. The hepatic extraction of butyrate showed a relatively large depression with grass feeding with nadir at 1200 to 1330 h. The increased net portal absorption and the decreased hepatic extraction resulted in an approximately six-fold increase in the arterial blood concentration of butyrate. The gut entry rate of urea accounted for 70 6 10% of the net hepatic production of urea. Saliva contributed to 14% of the total amount of urea recycled to the gut. Urea recycling to the gut was equivalent to 58% of the dietary nitrogen intake. Despite the severe undersupply of rumen degradable protein, the portaldrained viscera did not extract more than 4.3% of the urea supplied with arterial blood. This value is in line with the literature values for cows fed diets only moderately deficient in rumen degradable protein and indicates that cows maximise urea transfer across gut epithelia even when the diet is moderately deficient in rumen degradable protein.

show abstract

Section: Introductionmentioning

confidence: 99%

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Røjen

Lund

Kristensen

2008

Animal

View full text Add to dashboard Cite

show abstract

“…They consist of limiting the excess of protein digested in the small intestine and balancing the level of rumen-degradable protein (RDP) with the available energy supply for microbial protein synthesis (Colin-Schoellen et al, 2000;Børsting et al, 2003). The RDP balance according to the Dutch system (OEB; Tamminga et al, 1994) makes it possible to put this second strategy in practice.…”

mentioning

confidence: 99%

Effect of rumen-degradable protein balance deficit on voluntary intake, microbial protein synthesis, and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed corn silage-based diet1,2,3

Valkeners

Thewis

Laere

et al. 2008

Journal of Animal Science

View full text Add to dashboard Cite

“…Despite the diets having the same protein level, the soyabean contains large amounts of degradable rumen protein, which possibly contributed to the linear increase in nitrogen excretion. In addition, the increase in soyabeans in the diets led to considerable increase in rumen ammonia; however, this did not increase the microbial protein synthesis, though there was consequently an increased excretion of this nitrogen by urine (Børsting et al, 2003).…”

Section: Discussionmentioning

confidence: 95%

Effect of different dietary inclusion levels of whole raw soyabean on ruminal fermentation and nutrient utilization in Nelore steers

Cônsolo¹,

Gandra²,

Gardinal³

et al. 2017

J. Anim. Feed Sci.

View full text Add to dashboard Cite

Reducing nitrogen surplus from dairy farms. Effects of feeding and management

Cited by 67 publications

References 25 publications

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Effect of rumen-degradable protein balance deficit on voluntary intake, microbial protein synthesis, and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed corn silage-based diet1,2,3

Effect of different dietary inclusion levels of whole raw soyabean on ruminal fermentation and nutrient utilization in Nelore steers

Contact Info

Product

Resources

About