Storage of hay. III.—effect of temperature and moisture on loss of dry matter and changes in composition

Abstract

Ryegrass, clover and lucerne hay were stored a t each of several temperatures between -18" and 36" and moisture contents of (nominally) 7, 12 and 17% for about g months. Dry-matter losses increased with period of storage and with increase in both temperature and moisture, reaching a maximum of about 8%.Changes in the more important chemical constituents were also determined : (i) It was possible that soluble nitrogen contents decreased at temperatures of zx0 and 36" when the moisture content was 17%.(ii) Crude fat contents decreased with increasing temperatures and moistures, the effects of which were independent of each other.(iii) Carotene contents decreased with increasing temperatures, but there was no effect of moisture over the range examined.(iv) Total contents of go%-ethanol-soluble sugars decreased with increasing temperatures, but there was no effect of moisture with contents of 7 and 12%. At 17% moisture both temperature and moisture appeared to enhance the sugar losses.(v) Fructosan contents of ryegrass were not affected by temperature nor was there any change a t moisture contents of 7 and 12%, but a decrease occurred during storage a t 17y0. moisture.Dry-matter losses did not appear adequately to represent nutritional losses when compared with the chemical changes in constituents. - IntroductionDeterioration during the storage of hay depends primarily on the protection provided from weather and vermin, but even when hay is completely protected from the direct effect of factors such as these, gradual changes can still occur in the chemical constituents and these may be accompanied by a loss of dry matter.Apart from the results of investigations concerned with the loss of carotene there is comparatively little published information on the changes which occur in hay during storage, and such reports as are available seldom specify the conditions of storage (temperature and moisture content) with any degree of precision. Watson1 refers to a paper by Honcamp et at. published

Comparison by direct animal calorimetry of the net energy values of an early and a late season growth of herbage

“…This method of preservation was preferred to heat-drying which may alter nutritive characteristics (Christian and Williams, 1957) and to storage of the fresh material under refrigeration (Raymond, Eyles and Caukwell, 1949) which would have been incompatible with direct animal calorimetry. Work reported by Greenhill, Couchman and De Freitas (1961) and Melvin (1963) suggests that changes in composition during storage would have been very small. During drying the temperature of the herbage remained at about freezing point for 6 to 8 hours and then rose towards a maximum of 60° C. during the final 1 to 2 hours of drying which was complete after about 10 hours.…”

Influence of Drying and Storage Conditions on Nonstructural Carbohydrate Analysis of Herbage Tissue—a Review

“…Studies in Australia (6, 10) showed that loss of DM (principally the nonstructural carbohydrates) for white clover, lucerne, and ryegrass herbage increased with increased storage temperature (-18°, 7°, 21°, and 36°C), with increased tissue moisture (7, 12, and 17 %) and with storage time (up to 9 months) DM losses were about 8% after 9 months storage at 36°C and 17% moisture. Sugars soluble in 90% ethanol decreased with increasing temperatures, but there was no moisture effect at the 7 and 12% moisture levels.…”

Relating Sugar Fluxes during Bale Storage to Quality Changes in Alfalfa Hay

“…This can be attributed, in part, to the 30°C temperature threshold used to describe unsatisfactory storage in model hay bales (Baron et al, 1991;Coblentz et al, 1996). Respiration is known to occur both at elevated internal bale temperatures (>30°C) and at temperatures <30°C (Wood and Parker, 1971;Greenhill et al, 1961); however, in the second condition, heating degree days are not accumulated. These conditions would clearly be more common in lowmoisture treatments and would partly account for the faster rates.…”