Two experiments were conducted to determine the effects of Yucca schidigera extract (YE) on firstly, dry matter intake (DMI), milk production and milk composition in lactating Holstein Friesian cows and secondly on DMI and GEI and rumen fermentation parameters of ruminally fistulated Holstein Friesian steers. Three levels of YE supplementation were studied in both experiments. In Experiment 1, 33 early lactating dairy cows that were 69 days in milk (S.D.±39) at commencement of the trial were fed YE at either 0, 25 or 50 g/head/day in a randomised block design while in Experiment 2, the three fistulated steers were fed YE at 0, 15 and 28 g/head/day within a latin square design. The lower levels of YE supplementation fed in Experiment 2 were designed to provide similar inclusion rates within the diet as in Experiment 1 after allowing for the higher DMI within Experiment 1. All animals in both trials were offered ad libitum a total mixed ration (TMR) supplemented with concentrates containing the YE. The dairy cows were group housed by diet, however when milk and intake measurements were conducted (days 12 to 18 and days 54 to 60 post commencement of the feeding of the experimental diets) the animals were housed in individual tie up stalls, whereas for Experiment 2 all animals were individually stall fed for the duration of the trial. Feeding YE had no effect on milk yield or composition, however DMI decreased linearly (P<0.06) in response to increasing YE dietary inclusion within Experiment 1. No effects of YE supplementation on total tract digestibility were identified in either experiment, however comparisons between treatments revealed that total volatile fatty acid (VFA) concentration in rumen fluid were lower at for both YE25 and YE50 relative to the control, and rumen protozoa numbers were also linearly (P<0.01) reduced. Although feeding YE to early lactation Holstein Friesian cows had no effect on milk production or digestibility and had only elicited limited responses in rumen fermentation characteristics it would appear to lead to an increase in the efficiency of converting feedstuffs to milk (as comparisons between individual treatments revealed a significant increase following YE supplementation relative to YE0) due to a reduction in voluntary DMI.

Teaoil Camellia (Camellia oleifera Abel.) is a promising horticultural crop that has been cultivated for various purposes in China for more than 1000 years. It is a small tree, which grows naturally from latitudes of 18 degrees to 34 degrees North and in acidic soils where January mean temperatures do not drop below 2 degrees C. As cooking oil, it compares favorably with olive oil, stores well at room temperature, and has a high smoke temperature. Teaoil is also used in the manufacture of soap, margarine, hair oil, lubricants, paint, rustproof oil and other compounds with a high-molecular weight as well as in cosmetology and dermopharmacy. Extracts from the residues of teaoil processing have been used in livestock feeds, pesticides and fertilizers. The use of tea oil products in controlling rice blast and wheat rust also suggests potential for the development of new biological-based pesticides from this plant. Although edible tea oil production covers about 40,000 km(2) in China, other countries know little about this species, only planting it as an ornamental plant. To share this valued crop to the world, selecting promising clones for targeted habitats is the key to success. Cloning propagation using hypocotyl grafting is recommended. Management practices, such as preparing planting sites with organic fertilizer, controlling weeds, thinning, pruning, alternating harvest time, improving harvest techniques, etc., could significantly increase the economic return for C. oleifera plantations. Further studies on the genetic improvement of tea oil will improve its popularity around the world.

The in vivo determination of methane (CH4) production requires specialist equipment which is costly to maintain. Whilst the in vitro gas production technique has been demonstrated to show potential to rank diets for their methanongenic potential at maintenance planes of nutrition (Moss and Givens, 1997) no study has investigated this relationship when feedstuffs are fed ad libitum. The objective of this study was to assess the ability of the technique to predict in vivo CH4 production and animal performance from six diets differing in their chemical composition.

Intake, animal performance and methane (CH4) output was investigated using 36 finishing Charolais cross heifers (mean starting weight 462 kg, S.D.±16) fed ad libitum over an 11-week period. Six dietary treatments were investigated in a randomised block design experiment with a factorial arrangement of treatments. The six experimental diets consisted of three forage/concentrate (F/C) ratios (0.65:0.35, 0.40:0.60 and 0.10:0.90) supplemented with two levels of coconut oil (0 or 350 g/day). Rumen protozoa numbers were significantly (P<0.001) lower for diets containing coconut oil at the end of the trial. Reducing the F/C ratio resulted in significantly (P<0.001) increased rates of live weight gain (LWG) and carcass gain (CG), but coconut oil had no effect on animal performance. Methane output in litres per day was significantly modified (P<0.001) by both the F/C ratio and level of coconut oil. Maximal CH4 output was recorded on the 0.40:0.60 diet, with coconut oil reducing daily CH4 output regardless of the F/C ratio. Methane output per unit of animal product (per kg of LWG and carcass gain) was significantly reduced by lower F/C ratios and the dietary inclusion of coconut oil (P<0.001 and P≤0.003, respectively). No significant (P>0.05) interaction between the F/C ratio and coconut oil level was identified although coconut oil significantly reduced dry matter intake (DMI), CH4 l/day and LWG on the 0.65:0.35 F/C ratio diet.