Effects of formaldehyde treatment of high quality pasture hay on its utilization by weaner sheep

Abstract

Pasture hay of 18 per cent crude protein content was chaffed and sprayed with an 8 per cent solution of formaldehyde in a concrete mixer. This, or similar untreated chaffed hay was fed to Merino weaner sheep in four experiments as follows: 1. Twenty-four sheep grazing in a 0.9 ha paddock were penned individually three times a week and fed 700 g of either treated or untreated hay. During the intervening periods they were released and allowed to graze. 2. Twelve sheep penned indoors were given 300 g day-l of either treated or untreated hay as a supplement to a basal diet of hay which contained nine per cent crude protein. 3. Twelve sheep penned indoors were fed either treated or untreated hay ad libitum. 4. Six sheep in metabolism cages were fed either treated or untreated hay at a daily rate of 52 g kg-I liveweight0.75 A crossover experimental design was used. Wool production, body growth and, in experiment 4,nitrogen balance were recorded. Attempts were also made to gauge the effectiveness of the treatments in protecting the protein from ruminal degradation. Although the level of protection obtained compared favourably with that obtained by other workers with forages, significant differences in animal production were shown only in experiment 2, where the basal hay was utilized less efficiently for body growth when the supplement was treated, in experiment 3. where treated hay was utilized less efficiently for body growth, and in experiment 4, where wool growth was increased by 10 per cent and nitrogen retention was also increased by treatment of the hay. It was concluded that the magnitude of any likely beneficial response to treatment is too small to warrant this treatment of hay being undertaken on a large scale.