Effect of prolonged spring grazing on the yield and quality of forage from wild-hay meadows

During the 7-year period, 1936-42 inclusive, three fields used for wild-hay production were grazed from beginning of growth to about May 3, May 26, and June 9. After spring grazing for the time specified in the study, the native forage plants were allowed to grow until late July or early August when all three fields were harvested for hay at about the same time. Just previous to haying, 20 4X4-foot plots in each field were harvested, all within a 48-hour period, and the forage dried to constant air-dry weight. From these samples, hay yields were calculated and samples were drawn for chemical analysis in which standard methods were used to determine crude protein and total ash. Careful records were kept as to the grazing days of each age class of cattle, from which the amount of pasturage was calculated and added to the weight of hay to get total forage yields from the three fields grazed to early, mid-, and late spring. In the fields in which grazing was continued to late spring the hay had a shorter growing period and decrcased slightly in yield. When the pasturage taken was added to the hay, the total average forage yields were somewhat higher for the late-grazed area, being 1.79, 1.89, and 1.93 tons per acre for fields grazed to early, mid-, and late spring, respectively. Chemical analysis showed that for the 7 years, 1936-42 inclusive, the younger the hay, the higher the crude protein content. The crude protein percentages for the 7-year period averaged 8.13, 8.25, and 9.05 for the hay grown after early, mid-, and late grazing, respectively. The average acre-yields of crude protein were 291.1, 311.9, and 349.3 pounds an acre, which in relative numbers are 100, 107, and 120. The differences are highly reliable statistically. The relative yields for "total" mineral content were 100, 110, and 116. The total yields of protein and mineral matter were calculated on the basis that the contents of these constituents in the pasturage were the same as in the hay. The pasturage from young plants would most likely be higher in ash and definitely so in protein. Could this have been measured it would have increased still more the advantage for late grazing, as more pasturage was taken from the field that was grazed till late spring. When haying in two years was delayed 41 and 47 days beyond the bloom period of the plants, the hay from all three meadows further deteriorated in protein content. Since the increases in yield of hay did not nearly compensate for the decrease in protein, it was concluded that it is better to cut the hay early and pasture the aftermath.