At Beef Discussion Group meetings there is quite a lot of debate on the value of a short compact calving period. Most producers accept that a 365 day calving interval is important as they can easily see that every day longer than that means less calves within the year and most likely lighter animals at sale. However, some argue that if a cow has a calf every 365 days, the date or month of calving is not important. One suckler farmer said recently that “the boat sails every month” and if you have the right quality weanling you will get a good price whenever it is ready for sale.
It is evident from the HerdPlus calving report that on many suckler farms, cows are calving for 8 to 10 months of the year and this is occurring in herds of all sizes. All BTAP discussion group members are now members of HerdPlus. Print off the calving report for your herd and see what your calving spread is. Surely this wide calving spread is not as a result of planned breeding but arises from unacceptable poor fertility – slow return to breeding after calving and below average conception rates. I believe that a 365 day calving interval and compact calving go hand in hand, as herds with compact calving have a satisfactory calving interval, whereas a long drawn-out calving period is a good indication of failure of cows to calve within the year.
One argument raised against very compact calving is the requirement for a greater amount of calving facilities. Possibly the only time when this could cause a difficulty is in the early spring calving herds.
In the autumn, cows can all calve outdoors and from early March onwards it should be possible to either turn cows out soon after calving or turn out other stock which will free up sheds for cows with calves. Also, on many farms there are old hay sheds and other buildings that could be used as temporary calving boxes.
You must aim to have 60% of the herd calved in the first month of the calving season and all cows calved within 12 weeks. I believe most farmers would like to achieve these targets. For example, if the first cows calve on February 1st you would want to have all cows calved by May 1. The advantages of more compact calving include:
o Less labour and time spent supervising cows at calving.
o Less disease as there is less mixing of calves of different ages.
o Improved heat detection if using A.I. as if more cows in the herd are at the same stage in the reproductive cycle or in heat together there is stronger heat behaviour.
o Calves that are born earlier have a higher weaning weight.
o The herd can be treated as a unit for feeding, weaning, parasite control and grassland management. It also • keeps numbers of grazing groups to a minimum.
o Facilitates marketing as a uniform group of weanlings, stores or finishing cattle.
o Provides a uniform group of replacement heifers at breeding.
Where there is a very long calving season you cannot hope to compact it fully in one or two seasons. The first thing to do is rectify the deficiencies that may have led to it in the first place, e.g., cow condition, bull fertility, poor heat detection. Then over a 2-3 year time-span you can achieve a much more compact calving pattern by: more severe culling of late calvers; bringing in additional replacements that calve earlier than the main herd; delaying the very early calvers; removal of calves and only allowing them to suckle once or twice per day for the late calvers and; using synchronisation on the late calvers and heifers.
After fantastic temperatures and grass growth rates in March the temperature in April has dropped significantly with a consequent drop in grass growth. As a result grass is beginning to get scarce on some farms. Production can be increased in two ways: (i) apply 0.5-0.75 bags urea or one bag CAN/ac after grazing; and, (ii) have a large number of grazing divisions and a small number of grazing groups.
The greater the number of divisions you have the shorter the time animals will spend in each division, and the longer the interval between each grazing within the rotation. There is little or no growth in a paddock while it is being grazed down; therefore, the faster you get stock off, the faster the recovery. Aim for six to eight divisions per group and if soil conditions allow divide these in two while grass is scarce to allow you to ration grass more accurately and maximise growth on the paddocks that are in recovery. Keep the number of grazing groups as small as possible, e.g., two or three groups. Having a few cattle in most fields delays growth and response to nitrogen, especially when grass covers are low.
At this time of year, when growth rates are increasing, you don’t need high grass covers in paddocks and you can graze very tight (down to 3.5cm) when conditions are good. Growth should average about 40kg DM/ha/day in April. If the weather is wet, management will inevitably be much more difficult. When grass is scarce the two things you must avoid is grass wastage and poaching. This may involve taking some stock indoors, while leaving priority stock outside.
When grass is scarce, spreading out stock over more ground could reduce poaching but will delay the build-up of grass cover. Allowing stock to graze off their daily allowance in a few hours and then removing them to the house or to a sacrifice area maintains the rotation plan while reducing the damage. Try to avoid grazing when there is heavy rain. A few hours drying makes a difference to ground conditions. If grass is plentiful you have the option of spreading out stock or leaving higher post-grazing covers. Make sure to graze these areas out well in the next rotation.
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