Animal Management
Time to re-think feed planning
By Dr Ken Geenty
Now the winter months are with us it’s a good time to re-visit feed planning and budgeting for your sheep and cattle over the coming year.
The idea is simply to best match pasture supply and animal feed demands as shown in the generalized Fig. 1 example. Some of you may be daunted by the structured approach but success in meeting livestock target weights needs these workings. Fundamental are your ability to estimate available pasture drymatter (DM), effective monitoring of animal liveweights and knowledge of animal feed requirements.
There are feed planning software packages and apps available but even if these are used, a working knowledge of the underlying principles is invaluable. The concepts are well within your grasp by simply developing the required skills and having access to up-to-date sheep and cattle feeding tables. Bringing it all together may require participation in training exercises with a proficient colleague or your farm management consultant.
The essentials you will need for effective feed planning are:
- Accurate knowledge of paddock and farm areas
- The ability to measure or visually assess the amount of pasture in a paddock
- A knowledge of seasonal pasture growth on your farm
- Access to up-to-date sheep and cattle feeding tables
The basis of feed planning is estimation of grazing days in a paddock. The worked example in Table 1 is simplified for ease of grasping the fundamentals.
The same method can be used for other classes of stock using stock units and values from up-to-date feeding tables. If pasture growth is significant at say 80kg DM/ha/day = 400kg DM it should be included. In the above example this would still only have a small impact by increasing grazing days by 400/1500 = 0.26 of a day. However in larger paddocks the influence of pasture growth will be more significant, particularly during more rapid spring growth.
Once this paddock basis of feed planning is mastered the final three steps of a whole farm feed budget include:
- Setting up a rotation or set-stocking system
- Compiling a feed budget
- Reconciliation of stock carried
Stock Units
A stock unit is based on a ‘standard breeding ewe’ rearing on average 1.5 lambs and consuming about 6000 mega joules of metabolizable energy (MJME) a year. (NZ Society of Animal Production)
On this basis generalized equivalent su of different classes of stock are:
Class of stock SU
- Standard breeding ewe 1.0
- Dry-ewe/hogget 0.6-0.8
- Beef breeding cows 6-7
- 18-month steers 5-6
Rotational Grazing or Set Stocking
Research has not shown any clear efficiency or production advantage for either grazing management system. Generally the time of year or personal preferences will help decide the best option for you and combinations may well be chosen. Rotational grazing is most effective for rationing pasture. Set-stocking is less labour intensive and depends on pasture growth being adequate to meet animal feed requirements. What may work well for your neighbour may not be the answer for you. In making the above decisions you must have in mind seasonal pasture growth and animal feed requirements for your farm. Key considerations are:
- getting through the winter period
- handling the spring pasture surplus
- coping with summer-autumn challenges
The grazing management system chosen should be best to manage the pasture deficits/surpluses likely for your farm as shown in the Fig. 1 example. In this example pasture deficits in summer, autumn and winter exceed conserved spring feed surpluses. This indicates feed may need to be bought or stock carrying capacity reduced to better equate your farm feed supply and demand.
Feed Budget
A feed budget will allow you to relate pasture supply with animal feeding needs during the year. Importantly it will identify expected pasture deficits and allow them to be countered by options such as nitrogen application, cropping and hay conservation or buying.
The broad aim with feed planning and budgeting is to maintain overall average pasture cover on your farm between 1000 and 2500kg DM/ha. If you go outside these limits for extended periods both animal and pasture performance will probably suffer.
The feed budget can be compiled manually or using a computer spreadsheet or specialist packages available online or through your consultant. You will need to continually review the feed budget according to seasonal changes, especially the unexpected. In summary the steps involved in constructing your feed budget are:
- reconciliation of stock carried
- regular assessment of pasture cover
- calculation of feed supply and demand
Reconciliation of stock carried
The numbers of stock carried on your farm will be dependent on your policy decisions regarding:
- what am I good at and like doing? – eg. specialising in lambs or wool or weaner cattle
- is this a store or finishing farm – or a bit of each?
- is my stock policy too complicated?
- where is my profit from?
- ewes
- lambs
- ewe hoggets
- breeding and/or finishing cattle
Stock ratios
A very important part of your chosen livestock mix is sheep-cattle ratios. There are known production benefits from integrating sheep and cattle as they complement each other. Cattle cope better with longer rank feed while sheep are good at maintaining pasture quality by grazing lower and helping plant density.
Sustainable ratios of sheep to cattle stock units vary considerably from say 70:30 on hill country to 30:70 on easier country or up to 100% sheep or cattle on intensive finishing land.
There are important influences of different sheep:cattle ratios on stock carrying capacity and the pasture feed demand profile. Fifteen sheep SUs/ha do not equate with 15 cattle SUs/ha. As illustrated in Figs. 2 and 3 increasing proportions of cattle mean greater pasture demands and an overall reduction in stock carrying capacity.
Other aspects to consider are that as cattle numbers increase labour requirements overall are less but capital investment is much greater than for sheep. However higher performing farms generally have a greater proportion of cattle.
Ken Geenty is a primary industries consultant. This story was first published in Country Wide Magazine.