A trial was conducted to investigate the survival and digestibility of annual ryegrass (ARG) seed (Lolium rigidum L.) eaten by sheep and cattle. Sheep (n= 8) and cattle (n = 8) were fed a basal diet containing 1:1 lucerne chaff:oaten chaff with (ARG) or without (control) the inclusion of 20% total dry matter of annual ryegrass seed in a changeover design. Intake was restricted to 17 g/kg liveweight. Digestibility of the control diet was lower (P<0.01) for sheep than cattle. Annual ryegrass seed was present (P<0.01) in the faeces of both sheep and cattle within 24 h of first ingestion. Some 10.8 and 32.8% of seed ingested was excreted by sheep and cattle respectively, with 3.9% (sheep) and 11.9% (cattle) remaining germinable. Annual ryegrass seed continued to be excreted by both sheep and cattle up to 5 days after removal from the diet. Dry matter digestibility of the annual ryegrass diet was 53% in cattle.

Important factors in the successful uptake of grain legumes by cereal growers have been their capacity to increase soil N and control cereal disease, as these have underpinned high yields in following wheat crops. However, alternative 1-year legume crops are required to introduce additional biodiversity and management flexibility for cereal growers. The effects on soil mineral N and potential contribution to soil total N of other legume enterprises were studied. These included vetch (Vicia bengalhensis) or clovers (mix of Trifolium alexandrinum, T.�versiculosum, T. resupinatum) managed for green manure; pea (Pisum sativum), vetch, or clovers managed for silage; and clovers managed for hay. These were compared with pea and lupin (Lupinus angustifolius) managed for grain production. Wheat was also included as a control. The legumes were grown in acidic Red Kandasol soil at Wagga Wagga in southern New South Wales, in 1996, 1997, and 1998. Mineral N was measured in the autumn or winter of seasons 1997 and 1998 respectively. Amounts of stubble residue N were measured in all seasons. The green manure crops, particularly vetch, produced more mineral N than both grain legumes. The forage conservation crops (silage or hay) produced similar amounts of mineral N to grain pea and more than grain lupin. For the grain and green manure legume crops, variation in amounts of mineral N was explained by the total N content of legume stubble residue, but for the forage conservation crops, more mineral N was measured than was predictable from stubble N. The amounts of mineral N at different soil depths differed between legume treatments and experiments (sites and years). Based only on above-ground plant N, the green manure crops contributed more to increasing total soil N than grain legumes; in turn, the grain legumes contributed more than the forage conservation crops. It was concluded that alternative annual legume enterprises to grain legumes may provide at least similar enrichment of soil mineral N early in the following season, and that all annual legume enterprises may accumulate nitrate deep in the soil profile in some seasons.

The effect of annual 'break' crops on the yield and protein content of wheat was investigated over 3 seasons on a Red Kandasol on the south-western slopes of New South Wales. The 'break' crops included lupin and pea grown for grain, pea and vetch managed for silage, clovers managed for silage or hay, and vetch and clovers managed for green manuring. Wheat was sown for 2 years following the legume year, or canola and wheat followed the legumes. Averaged over 3 experiments the yields of first crop wheat following pea or vetch silage crops were comparable with those after grain pea. Yields following clover forage conservation crops or green manures exceeded those after grain pea by at least 0.41 t/ha; average yield increase after clover green manure was 0.93 t/ha. In one experiment, yields of second crop wheat were greater, by up to 0.37 t/ha, after forage conservation or green manure legume 'breaks' than after grain legumes. In 2 experiments, second crop wheat yields were greater after a first crop of canola than a first crop of wheat. Compared with continuous wheat yield, aggregate mean wheat yield increases were 3.5–4 t/ha following grain legumes, pea, and vetch silage crops, but 5.3–6.3 t/ha following clover forage conservation and green manure crops. However, the relative effects of legume treatments on wheat yield were significantly seasonally dependent. Yield and grain protein variation in wheat after legumes was significantly correlated with variation in mineral N at wheat establishment. However, in one experiment, yield was correlated only with variation in mineral N below the 20-cm soil depth, whereas protein was correlated only with variation in mineral N above the 20 cm soil depth. Yield increases in first crop wheat did not occur at the expense of grain protein.

A scoring system based on the position of the boundary (milkline) between the solid starch phase and the liquid phase on the surface of the maize kernel was evaluated as an indicator of crop stage of maturity. Milkline score (MLS) varies from 0 when the kernel contents are all liquid and no milkline is visible to 5 when the kernel contents are all solid and grain filling is complete. The scoring sytem is continuous in intervals of 0.5 units. The MLS was linearly related to the dry matter (DM) content of the cro in experiments at Nowra (R2 = 0.72), Wagga Wagga (R2= 0.82), and Grafton (R2 = 0.65). The predicted dry matter content at MLS 2.5 was 34.2% at Nowra, 36.0% at Wagga Wagga, and 33.7% at Grafton. Under normal seasonal conditions, milkline scoring can be used by farmers to help decide when their crops are ready for harvest. Crop DM is optimal for silage productions when MLS is in the range 2-3. However, the technique may not be reliable with severely stressed crops. Sampling 10 cobs from an area of 0.25 ha gave a 95% confidence of detecting the MLS with a precision � 0.37 unit. At Nowra the milkline moved down the kernel at a rate of 1 MLS unit/9 days. This rate may be different in other environments. At the same site there was a significant (P<0.05) quadratic relationship between milkline score and DM yield, with maximum yield obtained at MLS 3.4. However, this relationship accounted for only 16.76% of the variation, and clearly, other factors influenced DM yield.

Three experiments were conducted to study the effects of multiple suckling during early lactation on liveweight change, the interval to first postpartum oestrus, and post-weaning milk production of cows. The effects of liveweight change and butterfat production during the first six weeks of lactation on the interval to first postpartum oestrus in milked cows were studied in a fourth experiment. Multiple suckling caused greater liveweight loss in suckled cows during the first six months of lactation and stimulated postweaning milk production in two out of three experiments. Multiple suckling also delayed the onset of first postpartum oestrus. In experiment 4 the correlations of liveweight change and butterfat production with interval to first postpartum oestrus were low and non-significant. As suckled and milked cows received the same nutritional treatment, these results indicated that suckling per se, rather than nutritional effects, was the likely factor responsible for the delay in first postpartum oestrus in multiple suckled cows. A possible relationship between the stimulatory effect of suckling and plane of nutrition, and the application of the multiple suckling system to the dairy farm situation are discussed.