Potential impact of prickly pear cactus flour and Salix babylonica extract on cecal fermentation and methane production in horses

The cecal gas (GP) and methane (CH4) production and cecal fermentation kinetics when corn grain (CG) was replaced with prickly cactus (PC) in a horse’s diet at different levels of Salix babylonica (SB) extract was investigated. Three total mixed rations where CG was replaced with PC at three levels (/kg): 0 g (Control), 75 g (PC75) or 150 g (PC150) were prepared and SB extract added at four levels: 0, 0.6, 1.2 and 1.8 mL/g dry matter (DM) of substrates. No ration type 9 SB extract dose interaction was observed (P [0.05) for GP kinetics and CH4 production. Increasing the level of PC in the ration quadratically increased (P \0.01) the asymptotic GP and decreased (P\0.01) the rate and lag time of GP. Increasing the level of PC in the ration, increased GP values (P\0.05). Increasing the level of SB extract linearly decreased (P = 0.001) the lag time of GP of all diets without affecting the asymptotic GP or the rate of GP. Ration type and SB level had no effect (P [0.05) on CH4 production; however, at 36 h of incubation, SB extract decreased CH4 production. The rations PC75 and PC150 increased cecal pH compared with the control ration. The PC150 ration had the highest (P\0.05) DM degradability, short chain fatty acids production, and gas yield after 24 h of incubation, with no effect (P[0.05) of SB inclusion on all investigated fermentation kinetic parameters. It is concluded that increasing the level of PC in the diet of horse and replacing CG up to 60%, increased GP and improved cecal fermentation kinetics without affecting CH4 production. Inclusion of S. babylonica extract in the tested rations had weak effects on fermentation kinetics although it decreased the lag time of GP

Milk production from grass silage diets: effects of silage characteristics and the amount of supplementary concentrate.

AbstractHigh digestibility ryegrass was ensiled using either good methods including formic acid application (HDG) or poor methods without formic acid (HDP). Low digestibility ryegrass (LDG) and lucerne (LUC) were ensiled using similar methods to HDG. Digestible organic matter in the dry matter (DM) in vivo (DOMD) for HDG, HDP, LDG and LUC were 0·756, 0·774, 0·645 and 0·562 respectively. Silages were offered ad libitum to 40 HolsteinFriesian cows in two Latin-square design experiments during weeks 8 to 22 of lactation either alone (experiment 1) or with 3, 6, 9 or 12 kg concentrate DM per day (experiment 2). Relative intakes of silage given alone were respectively 1·00, 0·44, 0·98 and 0·79. Low intake of HDP could not be predicted from silage analysis. In experiment 2, DM intake increased by 0·11 kg and milk yield by 0·24 kg for each 0·010 change in grass silage DOMD. Intake of HDG, LDG and LUC declined linearly with increasing concentrate, on HDP the effect was non-linear and intake increased up to the 6 kg level.In experiment 1, milk and protein yields were greatest on HDG, protein yield was higher on LDG than LUC and fat concentration higher on HDP and LUC. With supplementation milk yield was greatest on HDG up to the 6 kg level, at higher levels differences between silages were not significant. Fat concentration was highest on LDG and protein highest on HDG and lowest on LUC. On all silages giving the highest concentrate level reduced the concentration and yield of fat. Protein concentration increased up to the 9 kg level. Fat plus protein yields reached a maximum on HDG with 6 kg concentrate DM per day and with 9 kg on the remaining silages.</jats:p

Supplementation of grass silage-based diets with small quantities of concentrates: strategies for allocating concentrate crude protein

AbstractFifty-five multiparous Holstein-Friesian cows were used to evaluate the short- and long-term effects of varying the crude protein (CP) content of concentrates offered at a low level (5 kg/day) along withad libitumaccess to a high quality grass silage. Three dietary treatment groups in lactation weeks 4 to 22 received concentrates containing either 156 (L), 247 (M) or 338 (H) g CP per kg dry matter; from weeks 13 to 21, half of the L animals changed over to the H concentrate and vice versa so that there were five treatment groups (LL, LH, MM, HL and HH). Feeding M or H compared with L increased silage voluntary intakes (P&lt;0·05) and the yields of milk (P&lt;0·05), fat (P&lt; 0·05) and protein (P&lt; 0·01). Milk protein concentration increased with level of concentrate CP (P&lt; 0·05). Pattern of concentrate CP supply (comparison ofLH, MM and HL) had no significant effect on intake or yields of milk and milk solids across the experiment (weeks 4 to 21), though cows gained less weight on treatment HL than on LH (P&lt;0·05) or MM. Intake, milk and component yields were all markedly affected by a change in concentrate CP at week 13; there were positive effects of additional CP (LLv.LH) and negative effects of reduced CP (HHv.HL) on silage intake (P&lt;0·05), as well as milk yield (P&lt; 0·001), milk protein yield (P&lt; 0·001) and milk protein concentration (P&lt; 0·001). Responses to increased concentrate CP were of a similar magnitude in early and midlactation; extra concentrate CP can recover depressed yields and concentrations of milk protein in established lactation. Production responses to concentrate CP involved a concomitant increase in silage voluntary intake.</jats:p