Effects of condensed tannins in Lotus pedunculatus on its nutritive value for sheep. 2. Nitrogenous aspects

The effects of an established Trichostrongylus colubriformis infection on amino acid (AA) absorption from the small intestine and their availability to other tissues were determined in lambs 48 days post infection. The lambs were fed fresh Lucerne (Medicago sativa; , 800 g dry matter (DM)/day) and dosed with 6000 L3 T. colubriformis larvae for 6 days (n 5 5) or kept as parasite free controls (n 5 6). Faecal egg production was monitored every second day from day 22 to day 48. A nitrogen (N) balance was conducted on days 35 to 43 after infection, and digesta flow and AA concentration measurements were made on day 44. On day 48 after infection, blood was continuously collected from the mesenteric artery and vein, plasma harvested and AA concentrations measured. Faecal egg production peaked on the 26th day after infection (P , 0.001) and intestinal worm burdens on day 48 were greater (P , 0.001) in the infected lambs. Feed intake and liveweight gain were similar (P . 0.10) between control and infected lambs. Digestibility and flow of DM and N through the digestive tract were also unaffected (P . 0.10) by parasite infection. Despite a trend towards higher abomasal AA flux in the parasitised lambs (P , 0.10), apparent AA absorption from the small intestine and AA availability to other tissues were unaffected (P . 0.10) by infection. These results suggest that an established parasite infection had little effect on the intestinal absorption and availability of AA to other tissues in lambs fed fresh Lucerne.

Section: Discussionsupporting

confidence: 80%

Intestinal amino acid absorption in lambs fed fresh Lucerne (Medicago sativa) during an established Trichostrongylus colubriformis infection

Bermingham

Roy

Sutherland

et al. 2008

“…The amplitude of this effect varies according to forage species, CT content and structure. The CT in L. corniculatus led to a less-marked decrease in N digestibility (Waghorn et al, 1987;Chiquette et al, 1989) than the CT in L. pedunculatus (Barry et al, 1986;Waghorn et al, 1994b) or the CT in our sainfoin.…”

Section: Nitrogen Valuementioning

confidence: 66%

In vivo and in situ measurements of the digestive characteristics of sainfoin in comparison with lucerne fed to sheep as fresh forages at two growth stages and as hay

Aufrere

Dudilieu

Poncet

2008

In vivoandin situdigestive characteristics of sainfoin (Onobrychis viciifoliaL., a tannin-rich forage) and lucerne (Medicago sativa L., a tannin-free forage) were compared to evaluate the effects of condensed tannins (CT) and growth stage (vegetativev. early flowering) in experiment 1. In experiment 2, the hays of the two forages, harvested at early flowering, were compared. Ingestibility, organic matter digestibility (OMD) and nitrogen (N) retention were measured in sheep fed sainfoin and lucerne fresh forages and hays. The loss of dry matter (DM) and N from polyester bags suspended in the rumen, abomasum and small intestine was also measured using rumen fistulated sheep and other intestine fistulated sheep. Nitrogen content was lower in sainfoin than in lucerne. Content of CT in sainfoin decreased with growth stage (3.5 to 2.5 g CT/kg DM) and was lower for sainfoin hay (0.6 g CT/kg DM). Ingestibility and OMD did not differ between fresh-fed forage species. Total N tract digestibilityin vivowas much lower for sainfoin than for lucerne fresh forages (mean value 0.540v. 0.721,P< 0.001) and for sainfoin hay than lucerne hay (0.464v. 0.683,P< 0.001). In both species, N digestibility was not altered by growth stage. The rumen degradation of N was lower in sainfoin than in lucerne, resulting in a lower proportion of N intake excreted in urine. The intestinal digestibility of sainfoin was also lower than that of lucerne, resulting in a higher N excretion in faeces. Hence the efficiency of N utilisation by sheep (ENr) was similar (mean value 0.205 and 0.199 g N retained/g N intake for fresh sainfoin and lucerne, respectively). The coefficient of N retention by the animal was higher for sainfoin at the vegetative stage than for all the other forages. Nitrogen degradability in the rumen determined by the nylon bag technique (DegN) was lower for sainfoin than for lucerne when forages were studied both fresh (mean value 0.608 and 0.818, respectively) and as hays (0.631 and 0.767). The efficiency of forage N digestion (ENd) was higher for sainfoin at the vegetative stage. Compared with lucerne, sainfoin greatly increased thein situestimate of forage N escaping the rumen but decreased its intestinal digestibility.

“…Supplementing dairy cows with black wattle tannin (Waghorn et al, 1987) and from 2.27% to 3.83% when Lotus pedunculatus with 5.5% CT in the DM was fed (Waghorn et al, 1994b). Carulla et al (2005) reported an average reduction in N apparent digestibility of 11% when CT from black wattle was added (at 2.5% of the dietary DM) to either ryegrass, red clover (Trifolium pratense) or alfalfa (Medicago sativa) haylage fed to sheep, but OMD was only reduced by 2%, from 73.9% to 72.5%.…”

Section: Discussionmentioning

confidence: 99%

“…This suggests 0.6% black wattle CT in the dietary DM did not reduce intake, but rumen proteolysis was reduced (Waghorn et al, 1987 and1994b). The pasture contained 23.9% of the DM, exceeding requirements for milk production, and therefore 0.6% black wattle CT was unlikely to limit amino acid availability for milk production, and when 1.2% CT was given, the detrimental effects on MS production were minor.…”

Section: Discussionmentioning

confidence: 99%

Supplementing lactating dairy cows fed high-quality pasture with black wattle (Acacia mearnsii) tannin

Griffiths

Clark

et al. 2013

A reduction in urinary nitrogen (N) excretion from dairy cows fed pasture containing a high N concentration in the dry matter (DM) will have environmental benefits, because losses to soil water and air by leachate and nitrous oxides (N 2 O) will be reduced. Condensed tannins (CT) reduce digestion of N, and provision as a dietary additive could have nutritional benefits for production, but the amount required and the responses to different sources of CT on milk production have not been defined. Two experiments were conducted to evaluate effects of supplementation with CT extracted from black wattle (Acacia mearnsii De Wild.) on milk production and faecal N concentration by lactating dairy cows grazing a vegetative Perennial ryegrass (Lolium perenne L.)-based pasture. In one experiment, CT was administered as a drench, twice daily, to 38 multiparous Holstein-Friesian cows assigned to four treatments; control (CONT, 0 g/day), low CT (LCT, 111 g/day), medium CT (MCT, 222 g/day) and high CT (HCT, 444 g/day), grazing as a single group. The CT supplementation affected milk yield (P , 0.001) with a trend of declining milk yield as CT concentration increased from about 0.6 to about 2.9% of dietary DM. Milk urea nitrogen (MUN) decreased at MCT and HCT levels of supplementation (P , 0.01) but milk fat, CP and lactose percentage were not affected by CT supplementation. The CT supplementation increased N concentration in faeces for LCT and MCT treatments (P , 0.05), suggesting partitioning of dietary N away from urine. When CT was pelleted with grain, in a second experiment and fed twice daily as a supplement at milking, it reduced the acceptability relative to pellets without CT, and tended to lower milk production from 25.4 to 24.5 kg/day, although the decline was not significant (P . 0.05). The diet of cows fed pellets with CT contained about 1.2% CT in the DM but neither milk constituents nor MUN were affected by CT-supplemented grain (P . 0.05). These findings demonstrate beneficial effects for production of low concentrations (c. 0.6% DM) of CT from black wattle when given to cows grazing pasture with an N concentration of 3.8%, and suggest a diversion of N from urine, but when CT exceeded about 1.4% of dietary DM, milk production was depressed. The value of supplementing a pasture diet for lactating dairy cows with black wattle tannin extract will depend on costs of supplementation, returns from milk production and liabilities associated with N losses to urine.