Abstract

Twenty Jersey and 12 Friesian cows were individually offered freshly cut pastures that had received either 100-150 kg nitrogen (N)/ha (HN) or 25 kg N/ha (LN) as urea, either ad lib. or restricted to 70% of ad lib. Treatments were imposed for 2 consecutive 14-day periods during September and October 1993. Effects of N fertiliser on the chemical and botanical composition of pasture were minor. There were no significant effects of N fertiliser on mean fat corrected milk yield, (19.9 kg/day 4.0% FCM), milk yield (16.2 kg/day), milk fat % (5.6%), milk fat yield (0.9 kg/day), or liveweight change (-0.59 kg/day). Milk protein yield (P.0.05) and protein % (P<0.05) and protein % (P0.01) were greater for LN than for HN treatment groups (0.58 vs 0.56 kg/cow/day and 3.6 vs 3.5% respectively). Voluntary DMI was also affected by N fertiliser for cows on ad lib. pasture allowance (14.0 vs. 14.6 kg DM/cow/day for HN and LN treatments; P<0.01). The application of N fertiliser in winter/early spring, had only minor effects on pasture intake or milk yield and composition in early lactation.

JL, Woods, AR Bray, GR Rogers, and MC Smith

Proceedings of the New Zealand Society of Animal Production, Volume 55, , 42-45, 1995