Byproduct-based concentrates in Swedish dairy cow diets – evaluation of environmental impact and feed costs

Figures & data

Figure 1. System description.

Table 1. Dry matter intake (DMI), proportion of roughage, proportion of feed components in concentrate (% of DMI), and milk yield of dairy cows based on data from a feeding trial (Karlsson et al., 2018), recalculated to 305 days of lactation and 60 days of dry period. The treatments differed in type of concentrate

Concentrate type	Control	RS^a	DG^b	RS^a + DG^b
Total DMI, kg	7403	7406	7406	7407
Of which (% of DMI)
Roughage	60	60	60	60
Cereals	28	–	–	–
Other, non-byproducts^c	3.1	1.8	2.0	1.7
Cereal byproducts^d	–	3	1	3
Beet pulp	–	21	20	20
Distillers grain	–	–	14	6
Rapeseed meal^e	–	12	–	7
Soy products^f	8	–	–	–
Other byproducts^g	1.2	2.0	2.0	2.4
Milk yield
Produced, kg energy-corrected milk (ECM)	10,065	10,065	10,065	10,065
Delivered^h, kg ECM	9360	9360	9360	9360

^a RS, rapeseed.

^b DG, distillers grain.

^c Rapeseed, corn kernel, green pellet, fat, minerals.

^d Bran and middlings. ^eIncluding Expro, that is, heat-treated rapeseed meal.

^f Soybean meal, soybean expeller, soybean.

^g Ingredients representing <5%, that is, molasses, palm expeller, sunflower meal, pea residues.

^h 93% of milk produced was assumed to be delivered to the dairy plant.

Table 2. Calculated feed intake of different feedstuffs by recruitment heifers, in total kg dry matter (DM), during the rearing period of 27.3 months

	Control	Rapeseed (RS)	Distillers grain (DG)	RS + DG
Silage	2920	2925	2925	2925
Pasture	1407	1407	1407	1407
Concentrate (byproducts)	0	281	281	281
Concentrate for dairy heifers	513	240	240	240
Calf starter concentrate	44	44	44	44
Milk replacer	45	45	45	45

Figure 2. Carbon footprint (kg CO₂e) of feed composition per kg concentrate: (a) without direct land use change (dLUC) and (b) with dLUC included in the calculations.

Figure 3. Environmental impact of feed composition per kg concentrate in terms of (a) land requirement (m²), (b) potential eutrophication (g NO₃e) and (c) use of non-renewable energy (MJ).

Table 3. Environmental impact per kg ECM (recruitment heifers included), with and without allocation between milk (84%) and meat (16%), divided over different sources, for the environmental categories: (a) carbon footprint (kg CO₂e), (b) eutrophication (g NO3e), (c) non-renewable energy use (MJ) and (d) land requirement (m²). For carbon footprint in (a), part I shows results without emissions from land use change and part II shows results with emissions from land use change (dLUC) from soybean and palm oil production. dLUC is calculated according to PAS 2050 (BSI, 2012)

(a) Carbon footprint	Feed^a			Enteric fermentation	Manure management^b	Electricity at farm^c	Total no allocation	Total with allocation^d
kg CO2e	Total	Roughage	Concentrate
I. Without dLUC
Control	0.44	51%	49%	0.541	0.069	0.015	1.07	0.90
Rapeseed (RS)	0.49	46%	54%	0.529	0.069	0.015	1.10	0.93
Distillers grain (DG)	0.47	48%	52%	0.525	0.070	0.015	1.08	0.91
RS + DG	0.48	47%	53%	0.528	0.070	0.015	1.09	0.92
II. dLUC included
Control	0.79	28%	72%	0.541	0.069	0.015	1.42	1.19
Rapeseed (RS)	0.50	44%	56%	0.529	0.069	0.015	1.11	0.94
Distillers grain (DG)	0.48	47%	53%	0.525	0.070	0.015	1.09	0.92
RS + DG	0.49	46%	54%	0.528	0.070	0.015	1.10	0.93
(b) Eutrophication	Feed^a
g NO3e	Total	Roughage	Concentrate		Manure management^b	Electricity at farm^c	Total no allocation	Total with allocation^d
Control	39.1	59%	41%		7.34	0.00003	46.4	39.1
Rapeseed (RS)	29.7	74%	26%		7.33	0.00003	37.0	31.1
Distillers grain (DG)	28.6	80%	20%		7.36	0.00003	36.0	30.2
RS + DG	28.8	76%	24%		7.36	0.00003	36.1	30.4
(c) Non-renewable energy use	Feed^a
MJ	Total	Roughage	Concentrate			Electricity at farm^c	Total no allocation	TOTAL with allocation^4
Control	3.17	43%	57%			0.080	3.25	2.73
Rapeseed (RS)	4.27	32%	68%			0.080	4.35	3.66
Distillers grain (DG)	4.10	33%	67%			0.080	4.18	3.52
RS + DG	4.14	33%	67%			0.080	4.22	3.55
(d) Land requirement	Feed^a
m^2	Total	Roughage	Concentrate				TOTAL no allocation	TOTAL with allocation^4
Control	1.75	51%	49%				1.75	1.47
Rapeseed (RS)	1.18	75%	25%				1.18	0.99
Distillers grain (DG)	1.11	80%	20%				1.11	0.94
RS + DG	1.15	77%	23%				1.15	0.97

^a Includes production (including of inputs), feed losses, transport to farm and fuel consumption at feeding (e.g. taking silage out of the silo).

^b CH₄ and direct and indirect losses of N₂O from the house, storage and paddocks.

^c feeding, milking, manure management, light, ventilation.

^d allocation between milk and meat applied according to IDF (2015), that is, 84% of emissions allocated to milk and 16% to meat.

Figure 4. Carbon footprint of the feed rations of dairy cows and recruitment heifers, divided into roughage and concentrate, expressed in CO₂e per kg energy-corrected milk (ECM).

Table 4. Environmental impact of silage production per kg dry matter (DM)

	Carbon footprint	Land requirement	Energy use	Eutrophication	Leakage
	kg CO2e/kg DM	m^2/kg DM	MJ/kg DM	g NO3e/kg DM	g N/kg DM	g P/kg DM^a
Control	0.390	1.43	2.37	39.4	3.66	0.06
Rapeseed (RS)	0.385	1.43	2.38	37.6	3.60	0.06
Distillers grains (DG)	0.389	1.43	2.37	39.2	3.66	0.06
RS + DG	0.385	1.43	2.38	37.6	3.60	0.06

^a Weighted mean value for temporary grass-clover ley in Sweden.

Figure 5. Amount of (a) phosphorus (P) and (b) nitrogen (N) in feed consumed, milk produced and manure excreted per cow and year (excl. heifers) (left axis), and nutrient use efficiency (amount of P and N in milk as % of P and N in feed) (right axis).

Table 5. Annual cost of feed for dairy cows and heifers, in EUR (1 EUR = 9.633 SEK) per kg energy-corrected milk (ECM) delivered to the dairy plant, assuming silage production on-farm, summer pasture period and purchased concentrate.

	Roughage	Concentrate	Total cost
Control	0.123	0.114	0.237
Rapeseed (RS)	0.123	0.120	0.243
Distillers grain (DG)	0.123	0.116	0.239
RS + DG	0.123	0.117	0.240

Karlsson, J., Spörndly, R., Lindberg, M. & Holtenius, K. (2018). Replacing human-edible feed ingredients with by-products increases net food production efficiency in dairy cows. Journal of Dairy Science 101, 7146–7155. doi:10.3168/jds.2017-14209

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