@conference {41613,
	title = {In vitro production of volatile fatty acids from forages},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {50-54},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Volatile fatty acid (VFA) production from a range of fresh forages was measured in vitro over 24 hours (h). The forages comprised temperate and tropical grasses, legumes (including some containing condensed tannins; CT), herbs and silages, all of which were minced to resemble chewed forage and incubated in buffered media. Volatile fatty acid concentrations were measured in triplicate for each feed at 0, 6, 12 and 24 h. On average, VFA yields were 131, 226 and 311 mg/g dry matter (DM) between 0 - 6, 0 - 12 and 0 - 24 h, and the highest yields were from legumes (384 mg/g DM) and lowest from plantain (176 mg/g DM) after 24 h. Legumes containing CT produced 28\% less VFA than other legumes. The acetate + butyrate:propionate (A+B:P) ratio showed a substantial difference between forage types, ranging from an average of 2.5 (legumes) to 3.5 (tropical grasses) after 6 h, but differences between forage types diminished after 24 h. Multiple regression analysis showed a weak inverse relationship with NDF (neutral detergent fibre) after 6 h, but there was no clear relationship with particle size, chemical composition or digestion rates at 12 and 24 h. },
	issn = {1176-5283},
	author = {Burke JL and Waghorn GC and Brookes IM and Chaves AV and Attwood GT}
}
@conference {41147,
	title = {Formulating total mixed rations from forages - defining the digestion kinetics of contrasting species},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {9-14},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The work described here is the first step in formulating forage-based TMR rations for dairy cows, based on digestion kinetics derived from in vitro and in sacco incubations. Kinetic information has been obtained from 23 contrasting fresh and conserved forages species, including temperate and tropical grass species, legumes (including Lotus spp. containing condensed tannins), herbs, silages, lucerne hay and maize grain. All forages were minced to a particle size similar to chewed material. Estimates of DM solubility (\% DM) and fractional dry matter degradation rates (h-1) determined by in sacco incubations include: white clover (39\%, 0.195), perennial ryegrass (45\%, 0.114), tall fescue (46.8\%, 0.051), paspalum (27\%, 0.068), sulla (51.4\%, 0.121), chicory (41.8\%, 0.260), pasture silage (41\%, 0.083), maize silage (28\%, 0.042). In vitro incubations resulted in five-fold differences between forages in net ammonia release, 2-3 fold differences in volatile fatty acid yield and a three-fold difference in acetate:propionate ratio. The data will be used in simulation models to identify optimal forage mixtures for meeting the nutritional needs of high-producing dairy cows. },
	issn = {1176-5283},
	author = {Burke JL and Waghorn GC and Brookes IM and Attwood GT and Kolver ES}
}
@conference {41146,
	title = {Preparation of fresh forages for incubation and prediction of nutritive value},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {5-8},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {In vitro and in sacco digestion offers a rapid and inexpensive method for evaluating nutritive value of ruminant feedstuffs. This study compared the conventional freeze dried and ground (FD) preparation with chopping to 6-mm lengths (C) and mincing (M) to represent chewed forage. In sacco and in vitro comparisons were made with perennial ryegrass (RG), white clover (WC) and Lotus corniculatus (LC). The mean proportions of large (>1.0mm) and soluble dry matter (DM) for the three forages were: M, 0.38 and 0.44; C, 0.76 and 0.21; FD, 0.35 and 0.34 respectively. Disappearance of DM and crude protein (CP) during the first 12 hours of rumen incubation was substantially lower for chopped forages. Minimal lag times before the onset of protein degradation were observed following mincing. Yields of ammonia from proteolysis in in vitro incubations were lowest for C and usually highest for M preparations. Preparation also affected yield but not proportions of VFA. These data show that ranking of forages for digestibility is affected by preparation and mincing appears to be a more suitable preparation for assays than chopping and freeze drying and grinding. },
	issn = {1176-5283},
	author = {Barrell LG and Burke JL and Waghorn GC and Attwood GT and Brookes IM}
}
