No abstract

No abstract

This study compared the yield and nutritive content of conventional and leafy maize silage hybrids, and the expected differences in milksolids (MS) production if fed to cows. A range of conventional and leafy hybrids were planted in paired strip trials (n=162) or small plot trials (n=132) during spring 1999, 2000, 2001, 2002, 2003, and 2004 in all of the main maize silage growing areas from Nor thland to Canterbury. Pair ed comparisons of short, medium, and long maturity conventional and leafy hybrids were made. On average, conventional hybrids yielded 1824 kg DM/ha (9%) more than leafy hybrids and had a marginally lower fibre digestibility (0.6 percentage units). Modelling using the Cornell Net Carbohydrate and Protein Systems (CNCPS) model showed that leafy hybrids had a similar metabolisable energy (ME) content and MS per cow and per tonne of maize silage were not different. For dairy farmers growing their own maize silage crop to feed to cows, the planting of conventional hybrids will result in more MS and profit/ ha of maize grown than will the planting of leafy hybrids. If maize silage is purchased on a cent/kg dry matter (DM) basis, the small differences in nutritive content of leafy and conventional hybrids will not affect MS production or profit. Keywords: dairy cows, leafy hybrids, maize silage yield, nutritive value

Trade-offs in dry matter (DM) and metabolisable energy (ME) between combinations of three maize silage hybrids varying in maturity from 100-113 CRM and six winter forage options were investigated in a Waikato farmer's field over 2 years. Winter crops were triticale, cut once; oats grazed 1-2 times; and Tama and Feast II Italian ryegrass, each cut or grazed 2-3 times. Greatest DM and ME production (38.9 t/ha; 396 GJ/ha) was from a 113 CRM hybrid followed by a single-cut triticale crop. The most economical sources of DM and ME were obtained from a 100 CRM maize hybrid plus grazed oats (11.8 c/ kg; 1.12 c/MJ), while the cheapest ME source among cut winter forages was a 113 CRM maize hybrid + triticale (1.18 c/MJ). Reliable annual silage production of 30 t DM/ha and 330 GJ ME/ha (or 3000 kg MS/ha) is possible using a late maturing maize hybrid combined with a winter forage crop such as triticale, although the low feed value of the triticale may limit its use as feed for milking cows. Keywords: Italian ryegrass, oats, maize silage, supplements, triticale, winter forage crops

Maize is a drought tolerant crop that produces high dry matter yields. Growing maize silage as part of a pasture renewal programme can help improve pasture persistence by reducing the level of weeds, insect pests and carryover ryegrass seed. Feeding maize silage to dairy cows results in pasture substitution. This decreases grazing pressure and can be used to manipulate farm pasture cover levels reducing overgrazing. The combination of maize silage and a well-designed stand-off pad with feeding bins allows farmers to keep cows off wet pastures reducing pugging damage and subsequent losses in pasture production without compromising milk production or animal welfare. Maize hybrid selection is critical to ensure timely regrassing. Crop simulation models such as CERES-maize may be useful to determine the best maize hybrid maturity x planting date combinations required to maximise silage yield and meet desired silage harvest and regrassing dates. Best-practice maize silage management including seed bed preparation, weed control and insecticide-treated maize seed will help farmers achieve high yields of silage and assist in the subsequent establishment of high yielding and persistent pastures. Keywords: pasture persistence, maize silage, feed pad