Range of quality characteristics of New Zealand forages and implications for reducing the nitrogen leaching risk from grazing dairy cows

Figures & data

Table 1. Percentage ranges for crude protein (CP) and soluble sugar + starch (SSS) and associated index weighting for feeds giving best performance of lactating or non-lactating dairy cows, and best environmental outcomes.

Quality and/or environment parameter	Grouping for cow class or environment outcome	Quality ranges ^a			Index value			Index Sum^b (Range)
		CP (%)	SSS (%)	SSS:CP ratio	CP	SSS	SSS: CP ratio
1. CP and SSS	Lactating cows	<16, 16–20, >20 &	<25, 25–50, >50	–	1, 3, 1	1, 2 ,3	–	2–6
	Non-lactating cows	<10, 10–16, >16 &	<25, 25–50, >50	–	2, 3, 1	1, 2, 3	–	2–6
	Environment^c	<12, 12–20, >20 &	<25, 25–50, >50	–	6, 4, 1	1, 2, 3	–	2–9
2. SSS:CP ratio	Lactating cows	16–20 &	–	<1, 1–3, >3		–	1, 2, 3	1–3
	Non-lactating cows	10–16 &	–	<1, 1–3, >3		–	1, 2, 3	1–3
	Environment	–	–	<1, 1–3, >3	–	–	1, 2, 3	1–3
3. Combined CP and SSS	Lactating cows	12–20^d &	40–80, (other)^e	–		4, (1)	–	4, (1)
	Non-lactating cows	10–16 &	30–80, (other)	–		4, (1)	–	4, (1)
	Environment	<12 &	30–80, (other)	–		4, (1)	–	4, (1)
4. Combined Quality(Q) +	General	10–16 &	30–80, (other) &	<1, 1–3, >3		4(1)	1, 2, 3	1–7
and Environment (E)^c		<12, 12–20, >20 &	<25, 25–50, >50 &		6, 4, 1	1, 2, 3	–	1–9
Q + E								2–16
5. Optimum feed quality	Lactating cows	16–22 &	25–70
	Non-lactating cows	10–16 &	30–75		Selections determined on quality ranges only
	Environment	5–12 &	30–75

^aUse of ‘&’ indicates conditions satisfied for multiple columns; CP = crude protein, SSS = soluble sugars and starch.

^bSummed index values for component ‘quality’ or ‘environmental’ ranges for CP, SSS and SSS:CP ratio.

^cIndices for environment were doubled to accentuate the value of low protein feed as environmental solution.

^dRange extended to 12–20 to include a wider range of samples.

^eIf the condition was satisfied, the index value = 4, if not the index = 1.

Table 2. Nutrient composition (%), means (ranges) for forage crops and supplements in New Zealand.

Category	Crop	Published results	Total results	Crude protein	Soluble sugars and starch	ADF	NDF
Brassica	Kale	3	211	13.5 (3.6–30.3)	27.0 (10.7–49.0)	25.2 (13.9–43.9)	34.2 (14.2–62.0)
	Swede–leaf	0	15	24.5 (17.9–30.2)	19.1 (13.3–24.8)	16.9 (12.2–28.7)	17.1 (11.6–20.5)
	Swede–bulb	0	12	11.3 (9.1–14.4)	47.3 (42.1–54.9)	14.5 (11.6–17.6)	15.4 (12.9–18.5)
	Turnip–whole	2	48	12.6 (3.6–25.5)	23.3 (11.2–35.2)	32.8 (10.9–43.2)	41.7 (17.7–56.5)
	Turnip–leaf	0	19	21.8 (15.9–33.1)	19.7 (9.3–27.7)	22.1 (14.9–30.5)	26.2 (13.7–36.7)
	Turnip–bulb	0	21	13.4 (7.7–18.6)	38.0 (28.4–51.1)	19.9 (12.9–31.9)	26.6 (13.4–47.0)
	Rape	2	70	18.4 (7.3–31.1)	24.7 (6.3–46.4)	22.6 (12.8–30.5)	28.7 (11.9–42.7)
	Leafy turnip	2	10	21.8 (14.6–28.7)	24.8 (14.5–45.6)	23.3 (13.9–30.3)	27.8 (20.8–35.2)
Beets	Fodder beet–whole	11	36	7.6 (1.9–11.1)	48.6 (23.5–73.8)	19.1 (6.8–31.1)	30.9 (12.0–45.0)
	Fodder beet–leaf	1	22	21.2 (16.4–27.1)	–	15.2 (11.2–22.1)	29.8 (24.4–37.8)
	Fodder beet–root	1	23	7.9 (6.7–10.1)	72.5	6.7 (5.4–7.3)	11.7 (9.8–13.3)
Cereal Grains	Wheat	1	28	14.3 (11.6–17.0)	64.7 (51.6–72.1)	3.0 (0.4–6.9)	9.8 (7.0–16.9)
	Barley	1	10	12.8 (9.9–14.8)	64.4 (57.5–72.3)	11.7 (6.0–51.7)	14.8 (10.3–21.7)
Cereal Silage	Wheat	2	303	10.6 (4.0–26.9)	22.9 (6.0–45.6)	26.5 (0.4–43.4)	44.2 (16.4–70.0)
	Barley	5	467	9.5 (2–27.7)	23.2 (1.5–41.9)	28.0 (9.7–51.4)	49.5 (26.6–82.1)
	Triticale	6	441	10.8 (2.9–30.0)	19.5 (1.5–39.5)	29.5 (13.7–46.0)	49.2 (26.4–72.8)
	Oats	4	167	13.3 (5.3–31.1)	15.7 (3.7–42.4)	29.5 (17.1–41.0)	49.8 (32.8–69.1)
	Ryecorn	0	6	14.5 (6.3–25.4)	18.4 (8.0–41.6)	25.6 (19.0–34.7)	43.8 (32.2–61.1)
C4 silage	Maize	7	159	10.5 (2.7–32.1)	34.0 (4.2–50.0)	23.4 (4.4–38.2)	41.3 (13.2–67.6)
	Sorghum	5	11	15.4 (6.7–23.0)	6.7 (4.2–10.1)	34.6 (27.4–41.8)	59.3 (53.4–66.0)
	Sudan Grass	0	4	16.2 (14.6–18.4)	5.0 (4.0–5.9)	35.0 (33.6–35.9)	57.1 (55.4–58.4)
Legumes	Faba/Tick beans	2	5	18.3 (14.4–29.0)	19.8 (18.2–22.8)	23.0 (10.7–29.7)	30.5 (15.9–46.9)
	Lupins	2	4	26.3 (19.6–43.0)	16.4 (16.3–16.5)	24.2 (20.1–26.2)	30.5 (24.4–33.9)
	Lucerne	2	27	18.2 (6.7–23.8)	22.0 (8.9–54.2)	30.8 (20.3–41.2)	40.0 (30.8–56.8)
	Peas	2	24	14.4 (8.2–17.9)	27.3 (21.7–33.1)	27.4 (18.5–38.7)	36.7 (24.8–54.9)
	Sulla	2	7	21.0 (14.4–24.2)	11.3 (2.3–19.6)	27.3 (21.9–42.8)	39.4 (35.7–51.9)
	Red clover	1	6	15.6 (7.9–19.7)	13.3 (8.8–20.3)	31.0 (26.6–39.3)	38.3 (34.7–49.1)
Herbaceous	Chicory	1	111	23.5 (6.2–31.5)	13.6 (1.2–44.1)	21.0 (10.2–31.9)	35.4 (22.1–69.9)
	Plantain	0	60	20.7 (13.2–28.0)	11.1 (0.6–16.5)	23.2 (16.3–28.4)	32.5 (23.1–41.0)
Hay & Straw	Barley straw	0	7	6.5 (3.2–13.8)	3.4 (1–6.2)	37.8 (37.1–50.6)	70.7 (57.7–79.6)
	Ryegrass	0	4	6.0 (4.4–7.5)	12.7 (9.5–14.3)	37.8 (32.9–42.6)	64.4 (56.1–72.4)
	Linseed	0	6	8.7 (7.6–9.9)	8.7 (6.9–11.3)	48.9 (42.8–53.8)	60.1 (53.0–67.6)
	Lucerne	0	4	14.8 (13.6–15.8)	4.7 (2.2–7.4)	39.5 (32.9–43.5)	51.2 (41.0–58.9)
	Meadow	0	2	8.5 (6.5–10.4)	11.8 (9.7–13.8)	30.4 (27.1–33.6)	50.2 (46.5–53.8)
	Ryegrass	0	4	8.3 (4.2–14.6)	20.3 (3.6–37.6)	31.7 (26.0–40.4)	51.0 (41.7–68.4)
	Wheat	0	15	5.3 (3.1–7.5)	4.2 (1.4–10.3)	45.9 (40.7–52.7)	76.4 (62.0–88.1)
Other	Potatoes	0	6	16.8 (10.0–20.6)	21.4 (2.4–59.0)	19.0 (3.7–33.6)	29.1 (4–43.2)
	Sunflower	2	11	7.6 (5.2–13.0)	28.4 (10.7–38.3)	28.6 (22.2–35.9)	37.6 (29.3–46.6)

Figure 1. Cumulative probabilities in brassicas, cereals and maize for crude protein (A, C and E) and soluble sugars + starch (B, D and F) content. Ranges of crude protein requirements for non-lactating and lactating cows are shown in light and dark shading respectively. Dashed lines (---) for SSS indicate relatively low, medium and high levels.

Figure 2. Cumulative probabilities for crude protein (A, C and E) and soluble sugars + starch (B, D and F) content in legumes, herbs, sunflower and pasture. Ranges of crude protein requirements for non-lactating and lactating cows are shown in light and dark shading respectively. Dashed lines (---) for SSS indicate relatively low, medium and high levels.