Langston University Goat Research Extension

Estimating Supplemental Concentrate Needs

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Use this Supplemental Concentrate Needs Calculator to calculate the amount of a given supplement to meet requirements of metabolizable energy (ME) and metabolizable protein (MP) for different types of goats consuming various basal dietary forages. Enter the data into the table and then click the Calculate Supplemental Concentrate Needs button. The results will be displayed in the table at the bottom of the page.

Goats are raised in many different types of production systems; but, feeding components can be grossly categorized into two types: 1) basal forage plus supplemental concentrate (BFSC) and 2) totally mixed diet or ration (TMR). Most meat, cashmere, and Angora production systems entail the first type of feeding system, with greatest prevalence of TMR for dairy production systems.

With BFSC, concentrate is supplemented to provide needed energy and protein not supplied by basal forage alone. Therefore, to determine the composition and feeding level of supplemental concentrate, it is necessary to know energy and protein characteristics of forage, as an estimate of forage intake is needed also.

Feed tags for supplements typically list the CP concentration. Likewise, the CP concentration in basal forage can be determined by a commercial laboratory, or perhaps this can be estimated based on past levels in similar forage. For simplicity, the CP concentration in forage along with an assumed factor for converting CP to metabolizable protein (MP; MP concentrate (%) = 64.0 + (0.16 × rumen undegraded protein concentration, % of total CP) will be used.

A number of measurements are necessary to most accurately determine the rumen undegraded protein concentration (UIP) in forages and supplemental concentrates. However, as noted for calculation of MP requirements, knowledge of the general type of feedstuff can allow an adequate estimate of the UIP concentration for most practical purposes. For example, many fresh forage diets would probably have a UIP concentration of 20% (on a total CP basis), which means that 80% of the CP is degraded in the rumen. Dried forages would have a slightly higher UIP level (e.g., 30% for grasses). In general, as the dietary level of concentrate increases, the UIP level increases. Since not a large number of feedstuff UIP concentrations have been determined with goats, below is a table with UIP levels for cattle (Preston, 2000) that can be used until more values determined with goats become available. Typically, feed tags list the major ingredients, which then can be used along with the table below, to derive a reasonable estimate of the UIP concentration. However, default UIP values of 20% for the basal forage and 40% for the supplemental concentrate have been used in the input box below.

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Feedstuff	Total CP, % DM	UIP, % of total CP	TDN, % DM
Alfalfa cubes	18	30	57
Alfalfa, dehydrated,17% CP	19	60	61
Alfalfa, fresh	18	18	61
Alfalfa hay, early bloom	19	16	59
Alfalfa hay, midbloom	17	18	58
Alfalfa hay, full bloom	16	20	54
Alfalfa hay, mature	13	30	50
Alfalfa silage	18	16	55
Alfalfa silage, wilted	22	22	58
Alfalfa leaf meal	28	15	69
Alfalfa stems	11	44	47
Ammonium chloride	163	0	57
Ammonium sulfate	132	0	0
Bahiagrass hay	8	37	51
Bakery product, dried	12	30	90
Barley silage	12	20	59
Barley silage, mature	12	25	58
Barley straw	4	70	43
Barley grain	12	28	84
Barley grain, steam rolled	12	40	84
Beet pulp, wet	9	35	76
Beet pulp, dried	7	44	75
Beet pulp, wet, with molasses	10	25	77
Beet pulp, dried, with molasses	10	34	76
Bermudagrass, Coastal, dehydrated	16	40	62
Bermudagrass hay, Coastal	10	20	56
Bermudagrass hay	10	18	53
Bermudagrass silage	10	15	50
Birdsfoot trefoil, fresh	21	20	66
Birdsfoot trefoil hay	16	22	57
Blood meal	92	80	66
Bluegrass, Kentucky, fresh, early bloom	15	20	69
Brewers grains, wet	28	52	85
Brewers grains, dried	28	58	84
Bromegrass, fresh, immature	15	22	64
Bromegrass hay	10	30	55
Bromegrass haylage	11	26	57
Canarygrass hay	9	26	53
Canola meal, solvent	40	30	71
Citrus pulp, dried	7	38	79
Clover, ladino, fresh	25	20	69
Clover hay, ladino	21	25	61
Clover, red, fresh	18	21	64
Clover hay, red	15	26	55
Clover hay, sweet	16	30	53
Corn, whole plant, pelleted	9	45	63
Corn fodder	9	45	67
Corn stover, mature (stalks)	5	30	59
Corn silage, milk stage	8	18	65
Corn silage, mature, well eared	8	26	72
Corn grain, whole	9	58	87
Corn grain, rolled	9	52	87
Corn grain, flaked	9	57	93
Corn grain, high moisture	10	38	93
Corn and cob meal	9	52	82
Corn cobs	3	50	48
Corn screenings	10	52	91
Corn gluten feed	23	25	81
Corn gluten meal, 41% CP	46	60	85
Corn gluten meal, 60% CP	67	62	89
Cottonoseed, whole	22	38	95
Cottonseed, whole, delinted	23	39	95
Cottonseed hulls	4	45	45
Cottonseed meal, mechanical, 41% CP	45	51	80
Cottonseed meal, solvent, 41% CP	48	40	77
Diammonium phosphate	115	0	0
Distillers grain, wet	28	55	90
Distillers grain, barley	30	56	77
Distillers grain, corn, dry	28	62	90
Distillers grain, corn, wet	29	55	90
Distillers grain, corn with solubles	29	53	90
Distillers corn stillage	22	55	92
Distillers grain, sorghum, dry	32	62	85
Distillers grain, sorghum, wet	32	55	85
Distillers grain, sorghum with solubles	31	53	85
Distillers dried solubles	29	0	88
Fat, animal, poultry, vegetable	0	0	205
Feather meal, hydrolyzed	86	75	69
Fescue, Kentucky 31, fresh	15	20	64
Fescue hay, Kentucky 31, early bloom	18	22	65
Fescue hay, Kentucky 31, mature	11	30	52
Fish meal	66	60	74
Grass hay	10	30	58
Grass silage	11	24	61
Hominy feed	11	48	89
Lespedeza, fresh, early bloom	16	50	60
Lespedeza hay	14	60	54
Linseed meal, solvent	39	38	76
Meadow hay	7	23	50
Meat and bone meal, porcine/poultry	56	24	72
Molasses, beet	9	0	75
Molasses, cane	5	0	75
Molasses, cane, dried	10	0	74
Molasses, citrus	10	0	77
Molasses, wood, hemicellulose	1	0	76
Monoammonium phosphate	70	0	0
Oat hay	10	25	54
Oat silage	12	21	60
Oat straw	4	40	48
Oat grain	13	19	76
Oat groats	18	15	91
Oat middlings	17	20	90
Oat hulls	4	25	40
Orchardgrass, fresh, early bloom	14	23	65
Orchardgrass hay	10	27	59
Peas, cull	25	22	86
Peanut meal, solvent	50	28	77
Potatoes, cull	10	0	80
Potato waste, wet	7	0	82
Potato waste, dry	8	0	85
Potato waste, wet with lime	5	0	80
Potato waste, filter cake	5	0	77
Poultry byproduct meal	62	49	79
Poultry litter, dried	25	0	64
Poultry manure, dried	28	22	38
Prairie hay	7	37	50
Rice grain	8	30	79
Rice bran	14	30	68
Rice hulls	3	45	13
Rye grass hay	10	40	58
Rye grass silage	14	25	59
Rye grain	12	21	82
Sanfoin hay	14	60	61
Sorghum silage	9	30	59
Sorghum grain (milo), ground	11	57	82
Sorghum grain (milo), flaked	11	62	91
Soybeans, whole	40	28	93
Soybeans, whole, extruded	40	35	93
Soybeans, whole, roasted	40	48	93
Soybean hulls	12	28	77
Soybean meal, solvent, 44% CP	49	32	84
Soybean meal, solvent, 49% CP	54	32	87
Spelt grain	13	27	75
Sudangrass hay	9	30	57
Sudangrass silage	10	28	58
Sunflower seed, meal, solvent	38	27	65
Sunflower seed, meal with hulls	31	35	57
Sunflower seed hulls	4	65	40
Timothy, fresh, pre-bloom	11	20	64
Timothy hay, early bloom	11	22	59
Timothy hay, full bloom	8	30	57
Timothy silage	10	25	59
Triticale grain	14	25	85
Turnip roots	12	0	86
Urea, 46% N	288	0	0
Vetch hay	18	14	58
Wheat, fresh, pasture	20	16	71
Wheat hay	9	25	57
Wheat silage	12	21	59
Wheat straw	3	60	42
Wheat straw, ammoniated	9	25	50
Wheat grain	14	23	88
Wheat grain, hard	14	28	88
Wheat grain, soft	12	23	88
Wheat grain, flaked	14	29	89
Wheat grain, sprouted	12	18	88
Wheat bran	17	27	70
Wheat middlings	19	22	82
Wheat mill run	17	28	75
Wheat shorts	20	25	80
Wheatgrass, crested, fresh, early bloom	11	25	60
Wheatgrass, crested, fresh, full bloom	10	33	55
Wheat grass, crested, hay	10	33	54
Whey, dried	14	15	82

To estimate the need for supplemental concentrate, an estimate of forage intake is needed. The feed intake calculators can be used for this, unless there is already knowledge of how much of a particular type of forage is consumed by class of goat of interest. The next factor to be considered is potential associative effects. An associative effect can be defined as a response, such as in total feed intake, digestibility, performance, etc., when mixtures of feedstuffs are consumed that are not as would be expected based on consumption of the feedstuffs alone. Associative effects can be positive or negative. That is, in some instances feed intake, for example, might be greater or less than expected. An example of a positive associative effect is when a very low protein forage (e.g., 4 or 5% CP in weathered and(or) mature prairie hay) is fed and a high-protein supplemental concentrate (e.g., soybean meal) is given, resulting in an increase in forage intake. An example of a negative associative effect is when a moderate to low digestibility forage (e.g., TDN concentration of 40-50% is supplemented with a moderate to high level (e.g., 0.75-2.0% BW) of concentrate high in cereal grains like corn. In this case, the supplemental concentrate elicits a decrease in forage intake, or there is ‘substitution' of concentrate for forage.

There has not been a great deal of research on associative effects with goats compared with cattle or sheep. Thus, it is not possible to use a well accepted method of addressing the issue. Nonetheless, because associative effects are known to occur in goats, a simple system being used in another project of the Institute will be employed until further information is available.

For basal dietary forage > 6% CP and when the supplemental concentrate level is at least 0.5% BW (DM basis), the following formula is suggested to address negative effects on forage intake of supplementation with high energy feedstuffs.

SUBN = -1 * ((-0.0007 - (0.2491 × DMIBWS) + (0.7641 × DMIBWS2) - (0.2006 × DMIBWS3)) - ((55 - DIGF) × 0.04))

SUBN = change (negative or a decrease) in forage intake, expressed as a fraction of supplement intake (for example, if supplement is given at 1% BW (DM basis), and SUB is -0.6, then hay intake is decreased by 0.6% BW.
DMIBWS = supplement intake as % BW (DM basis)
DMIBWS2 = DMISBW squared
DMIBWS3 = DMISBW cubed
DIGF = digestibility of forage

DIGF can be calculated from ME concentration as: DIGF = (ME concentration, MJ/kg + 1.8749) / 0.1867.

For forages < 6% CP (DM basis) and supplements 15% or greater in CP concentration (DM basis), the following formula is suggested to address the positive associative effect of high-CP supplements on intake of low-protein forages.

SUBP = (1.0398 - (0.2323 × DMIBWS) - (0.7047 × DMIBWS2) + (0.3757 × DMIBWS3)) - ((6 - PTCPF) × 0.05)

SUBP = change (positive or an increase) in forage DM intake expressed as a fraction of supplement intake (for example, if supplement is given at 0.25% BW (DM basis), and SUB is 0.6, then hay intake is increased by 0.15% BW.
DMIBWS = supplement intake as % BW (DM basis)
DMIBWS2 = DMIBWS squared
DMIBWS3 = DMIBWS cubed
PTCPF = % CP in forage or basal diet

In most practical supplementation settings, associative effects will be minor and not worth considering. However, they will be considered here when sgnificant, perhaps resulting in change in projected forage intake and need for supplemental concentrate.

In some settings MP or CP will be relatively more limiting than energy. However, goats appear relatively more efficient in recycling nitrogen than cattle or sheep, which suggests that the likelihood of MP being more limiting than ME is at least slightly less for goats. Also, it is important to note that with low-quality forage, both ME and ME may be limiting, and frequently supplemental concentrate given to correct a ME deficiency will be more than adequate to also correct for a MP shortfall. Nonetheless, this should be tested, with use of whichever estimate of supplemental concentrate used (i.e., based on ME vs MP) that is greater. The corresponding estimate of forage intake is employed as well.

If the combination of the particular animal forage, and supplemental concentrate conditions results in an unrealistically high proportion of concentrate in the diet, then a change in one of these three factors is warranted. For example, perhaps the forage is simply too low in quality whatever the supplemental concentrate for relatively high animal requirements for ME and(or) MP. Or, a supplemental concentrate with a much higher level of ME and(or) MP could be warranted.

In this regard, this calculator also displays the concentrations of MP and CP in the supplement necessary to exactly meet the need when the amount of supplement is being based on ME. Likewise, the optimal ME concentration in the supplement is listed when the supplement amount was determined by the MP requirement. If no value is listed in a box then supplemental concentration was based on this factor (ME or MP) or, forage alone without supplemental concentrate satisfied the requirement.

In addition to calculation of MP intake, the requirement for and intake of rumen degraded intake protein (DIP) are estimated. In most instances, however, because MP intake is determined as the sum of microbial protein and feed protein passing from the rumen intact, when MP intake is adequate so too will intake of DIP be.

To estimate the dietary ME concentration of the basal forage as well as supplemental concentrate, often feed tags list the Total Digestible Nutrient (TDN) concentration. Likewise, most commercial feed laboratories estimate the TDN concentration based on analyses, such as for crude protein (CP) and various fiber fractions.

As an example of this calculator, the following conditions can be used.

Parameter Value

Age Mature

BW (kg) 50

ADG (g/d) 0

Me: Biotype Indigenous

Gender Female

Forage MEC (MJ/kg) 8

MP: Forage CP (%) 5.5

Concentrate TDN (%) 80

Concentrate CP (%) 20

Forage UIP (% CP) 20

Concentrate UIP (% CP) 40

The feed intake calculator with optional adjustments should be used. With 5.5% CP in the basal forage, the amount of supplement is based on MP rather than ME. Total ME intake is 8.03 MJ, which is slightly greater than the requirement of 7.95 MJ. Hence, the optional ME concentration in the supplement is 11.00 MJ, slightly less than the assumed concentration of 12.08 MJ/kg. Very importantly, since the basal forage had a CP concentration of 5.5% (less than 6%) and the supplement CP level was above 15% (i.e., 20%), the supplement had a positive associative effect on basal forage intake (initial projected intake of 1.62% BW without supplementation compared with 1.79% BW when the supplement was given).

Conversely, with a basal forage CP concentration of 7%, the amount of supplement is based on ME rather than MP. MP intake now is slightly greater than the requirement (i.e., 55.24 vs 43.11 g). This results in optimal MP and CP concentrations in the supplement markedly less than assumed. This example brings out the importance of knowing forage composition in order to design appropriate supplementation strategies.

The ME concentration can be calculated with these simple formulas:
ME (MJ/kg) = TDN (%) × 0.15104 and
ME (Mcal/kg) = TDN (%) × 0.0361.

Enter concentrate TDN (%)
ME (MJ/kg)
ME (Mcal/kg)

Enter forage TDN (%)
MJ/kg
Mcal/kg

1. Choose class of goat growing
mature
lactating
Angora

2. Enter body weight (kg)

3. Enter average daily gain (g/day)

4. Enter ME requirement (MJ)
or use

5. Enter MP requirement (g)
or use

6. Enter estimate of intake of forage without supplementation (% BW)
or use

(maintenance energy based on body weight alone)
or

(adjusted maintenance energy)

7.
Enter forage ME concentration (MJ/kg DM)
or
You can use the forage TDN calculator above and the ME concentration will be entered automatically.

8.
Enter supplemental concentrate ME concentration (MJ/kg DM)
or
You can use the concentrate TDN calculator above and the ME concentration will be entered automatically.

9. Enter CP concentration in forage (%)

10. Enter CP concentration in supplemental concentrate (%)

11. Enter UIP concentration in forage (% of total CP)

12. Enter UIP concentration in supplemental concentrate (% of total CP)

13. Enter forage % DM (default is 90%)

14. Enter supplemental concentrate % DM (default is 90%)

To convert from English to metric system,
enter your values here.
They will be automatically entered into the table to the left.

BW
lbs

ADG
lbs/day

Final estimate of total DM intake, which is that based on ME or MP, dependent upon the greater estimate of supplemental concentrate intake (kg):

Total DM intake (% BW):

Final estimate of supplemental concentrate DM intake, based on ME or MP (whichever is greater) (kg):

Supplemental concentrate DM intake (% BW):

As fed supplemental concentrate intake (kg):

As fed supplemental concentrate intake (% body weight):

Forage DM intake (kg):

Forage DM intake (% BW):

As fed forage intake (kg):

As fed forage intake (% body weight):

As fed total intake (kg):

As fed total intake (% body weight):

Supplemental concentrate DM intake (% total diet):

Forage DM intake (% total diet):

ME from forage (MJ):

ME from concentrate (MJ):

Total ME intake (MJ):

MP from forage (g):

MP from concentrate (g):

Total MP intake (g):

DIP requirement (g):

DIP from the diet (g):

Optimal supplemental concentrate ME concentration when the amount of supplement needed to meet the MP requirement was greater than that for ME (MJ/kg DM):

Optimal supplemental concentrate TDN concentration when the amount of supplement needed to meet the ME requirement was greater than that for MP (% DM):

Optimal supplemental concentrate MP concentration when the amount of supplement needed to meet the ME requirement was greater than that for MP (% DM):

Optimal supplemental concentrate CP concentration when the amount of supplement needed to meet the ME requirement was greater than that for MP (% DM):

Sources used in this calculation method are:

Luo, J., A. L. Goetsch, T. Sahlu, I. V. Nsahlai, Z. B. Johnson, J. E. Moore, M. L. Galyean, F. N. Owens, and C. L. Ferrell. 2003. Prediction of metabolizable energy requirements for maintenance and gain of preweaning, growing, and mature goats. Small Ruminant Research 53:231-252.

NRC. 2000. Nutrient Requirements of Beef Cattle, 2000 Update. National Academy Press, Washington, DC.

Nsahlai, I. V., A. L. Goetsch, J. Luo, Z. B. Johnson, J. E. Moore, T. Sahlu, C. L. Ferrell, M. L. Galyean, and F. N. Owens. 2004. Metabolizable energy requirements of lactating goats. Small Ruminant Research 53:253-273.

Sahlu, T., A. L. Goetsch, J. Luo, I. V. Nsahlai, J. E. Moore, M. L. Galyean, F. N. Owens, C. L. Ferrell, and Z. B. Johnson. 2004. Nutrient requirements of goats: developed equations, other considerations and future research to improve them. Small Ruminant Research 53:191-219.

UIP concentrations were derived from:

Preston, R. L. 2000. Typical composition of feeds for cattle and sheep. In: Beef 36(10), 10-20. Intertec Publ. Co. Overland Parks, KS.

For substitution and stimulation calculations, the following were some of the sources reviewed:

Horn, G. W., and F. T. McCollum, III. 1987. Energy supplementation of grazing ruminants. In: M. B. Judkins (Editor) Grazing Livestock Nutrition Conference. pp 125-136. University of Wyoming, Laramie.

McCollum, F. T., III, and G. W. Horn. 1990. Protein supplementation of grazing livestock: A review. Prof. Anim. Sci. 6(2):1-16.

Moore, J. E., M. H. Brant, W. E. Kunkle, and D. I. Hopkins. 1998. Effects of supplementation on voluntary forage intake, diet digestibility, and animal performance. J. Anim. Sci. 77(Suppl. 2):122-135.