This experiment was designed to evaluate small grain rye, annual ryegrass and triticale for winter/spring grazing by replacement doe kids as well as animal performance in terms of daily weight gain. The grazing area consists of a total of 4.5 acres, divided into 9 plots measuring .5 acre each. Each forage species was seeded in 3 different plots, thus the experiment consists of 3 replications.
All three forage species were sod-drilled on October 2, 1996. Wet conditions delaying the building of fences and water lines, and then hurricane Fran account for this late planting date. In the Piedmont, the best dates to plant winter annual grasses are between August 25 to September 15, with possible planting dates extending from August 20 to October 31. Small grain rye (variety Elbon) was seeded at 108 lb/acre, annual ryegrass (variety Marshall) at 33 lb per acre and triticale (variety Resource Seeds 102) at 104 lb/acre. All plots were fertilized with 50 lb N/acre in the form of ammonium nitrate on November 15, 1996 and again on February 21, 1997.
Grazing started with two animals, on February 25 for the small grain rye, and on February 28 for both the ryegrass and triticale. Four additional animals were added to each plot, on February 27 for the small grain rye and on March 1 for both the ryegrass and triticale. From that day on, 6 animals have been grazing on each plot (four fullblood Boer and two halfblood Boer doe kids), a total of 54 animals for the entire experimental area. Doe kids were born in late April-early May 1996. Their average live weight at the start of the experiment was 62 lb; the lightest and heaviest animals weighed 45 and 81 lb, respectively. Animals are moved to a fresh strip of grass 3 to 4 times per week and back fenced immediately. Goats gained an average of 0.31 lb /day during the first 47 days of the trial (Table 1), with animals grazing triticale performing slightly better. However, the 54-day gain was similar for animals grazing triticale and ryegrass. These daily gains are very satisfactory for goats of that age and weight fed only on grass. The body condition of the animals is excellent and most of them would grade "prime" on a live basis. Due to stem elongation and head formation resulting in a significant decrease in leaf to stem ratio grazing ended on March 31 for the small grain rye, on April 22 for the triticale, and on May 7 for the rygrass.
Herbage mass (amount or yield of dry forage per acre which is above soil surface) was determined on a weekly basis by clipping frames at ground level and by using a electronic pasture probe or a disc meter. The gradual increase in herbage mass from the first sampling date can be seen in Table 2. Small grain rye increased from 1700 lb/a on February 25 to 3500 lb/a on April 9, whereas ryegrass and triticale increased respectively from 1800 and 2100 lb/a on March 1 to 4100 and 3700 lb/a on April 16. The amount of herbage mass peaked on April 16 for the ryegrass (4300 lb/a) and on April 21 for the triticale (4600 lb/a).Therefore, a significant amount of stem material accounts for the high herbage mass present on the small grain rye on April 9 and triticale on April 21 (Table 2). The amount of herbage present on each plot on March 31 and the percent dry matter of that herbage are shown on Table 3. Assuming that on the average the forage contains 20% dry matter, an animal consuming 3 lb of dry matter daily to meet its nutritional requirements would eat 15 lb (3 lb dry matter / 20%) of fresh forage. Out of these 15 lb of fresh forage, 12 lb (15 - 3) are water, meaning that the animal would ingest approximately 1.5 gallons of water (12 lb / 8.3 lb per gallon of water), thus meeting most or all of its water requirements by consuming forage alone.
Table 1. Goat Initial weight and Average Daily Gain (lb)
|Forage Specie||Initial Weight (lb)||47-Day Gain (lb/day)||54-Day Gain (lb/day)|
|S. grain rye||60||.30|
Table 2. Herbage Mass (lb/acre)
|Forage specie||Feb 24||Mar 1||Mar 10||Mar 17||Mar 24||Mar 31||Apr 9|
|S. grain rye||1700||2000||2200||2400||3400||3400||3500|
Table 2. Herbage Mass (lb/acre) - continued
|Forage specie||Apr 16||Apr 21||May 1||May 7|
|S. grain rye|
Table 3. Herbage Mass (lb/acre) and % Dry Matter on March 31
|Forage||Plot 1||Plot 4||Plot 9||Plot 3||Plot 5||Plot 8||Plot 2||Plot 6||Plot 7|