Heifers on Target Calculator

Introduction
Calculate Growth rate required
Heifer Target Weight Chart
Calculate Growth Rate from Diet
Estimate Extra Production
Estimate Reduced Culling
Example Feeds
Typical Requirements

This app will help you check whether your heifers are likely to reach their target weights.

The Estimate Extra Production tool lets you estimate the extra production that might be achieved if heifers reach a target of 85% of the production of the mature cows.

The Estimate Reduced Culling tool helps you see the impact of heifers being lost early from the herd.

The weight calculator tool will let you enter the current weight and the target weight of your heifers and will help calculate the growth rate required to achieve your target weight.

The Growth Calculator tool will allow you to enter the diet you are feeding, and to see whether this diet is likely to achieve the growth rates you need

Heifer Growth Rate Calculator

This calculator is designed to work out what growth rate your heifers will need to achieve to meet their target.

Calving start date:
Calving weight:
Date:
Weight:
Growth rate required:		kg/day
As a rule of thumb, growth rates of 0.6-0.8 kg/day are fairly easy to achieve from pasture alone. Growth rates above 0.8 kg/day may require supplementary feed. You can use the Diet Calculator tool to see if your current diet is likely to pose a risk. Consult a nutritionist if your diet poses a risk of under-target heifers.

Heifer Target Weight Chart Tool

Date	Target (kg)	Age (Months)
Calving start date:
Calving weight:
Required Growth Rate:		kg/day




















		24

Heifer Diet Calculator

This calculator is designed to work out what growth rate your heifers are likely to achieve on their current diet.

Step 1. Current targets:

Current heifer weight:
Growth rate required:

Step 2. Requirements

Your heifers require:
Energy for Maintenance:		MJ
Energy for Growth:		MJ
Total Energy:		MJ
Protein % required:		%

Step 3. Pasture availability

What sort of pasture is available?

	ME	Protein	NDF

Step 4. What supplementary feed are you giving them?

Feed (in DRY MATTER)	MJ/Kg	Protein %	% NDF
Barley	12.4	11.3	20
Canola	12.5	39	20
Hay - average	8.5	10	60
Hay - good	10	14	50
Hay - vetch	10.5	18	45
Lupins	13	31.3	20
Palm Kernel Extract	11	17	57
Silage	10.5	15	50
Wheat	13.3	10.5	10


Summary:

Step 5. Analysis


Total Diet Protein %:

Max Pasture intake (kg):
Assuming the grass above and that heifers are eating as much as they can we can calculate the expected growth rate:
Total Diet Protein % :
Dietry ME from Pasture
Dietary ME from Supplements:
Total dietry ME (MJ):
Expected growth rate (kg/day):

(Note - these calculations are based on rules of thumb only. You should seek professional advice before acting on these calculations!)

I Herd Test

This tool estimates the increased production that might be achieved if heifers are "On Target"

Average Lactation Production (cows):		Litres
Average Lactation Production (Heifers):		Litres
Your heifers are producing this %:
If they produced 85% of the mature cows you could be producing this many more litres per heifer:
(you could produce more milk, or the same milk with less cows)

Estimate reduced culling

Herd Structure:

How many first calvers do you have ?		cows
How many second calvers do you have ?		cows
The ratio is
If you reached a target of 85%, No. of extra second calvers you might have:

Typical feed values

Feed	ME	Protein	NDF
	MJ/kg DM	%	%
No or very limited pasture	0	0	0
Pasture - Autumn	10	14	50
Pasture - Irrigated	11.5	22	40
Pasture - late spring	11	18	45
Pasture - lush spring	12	25	35
Pasture - Summer	9.5	12	55
Pasture - Winter	11.5	25	35
Barley	12.4	11.3	20
Canola	12.5	39	20
Hay - average	8.5	10	60
Hay - good	10	14	50
Hay - vetch	10.5	18	45
Lupins	13	31.3	20
Silage	10.5	15	50
Wheat	13.3	10.5	10

Typical heifer requirements

BW	Maintenance	Growth	Protein
Kg	mj/d	mj/kg	%
25	6	10.4	17
50	10	13.2	17
75	14	14.6	17
100	17	19.8	17
125	20	21.5	17
150	24	23.3	17
175	27	25.0	17
200	29	26.7	17
225	32	28.4	17
250	35	30.0	15
275	38	31.6	15
300	40	33.3	15
325	43	34.8	15
350	45	36.4	14
375	47	37.9	14
400	49	39.5	14
425	52	40.9	14
450	54	42.3	14
475	56	43.8	14
500	58	45.2	14
** These are rules of thumb only. Temperature, exercise and genetics and other factors will affect requirements (Adapted from Holmes CW, Wilson GF (1987) Milk Production from Pasture)

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