Stocking rates in pens will directly impact on animal performance. If pens are overstocked, animal performance will suffer.
This is due partly to restricted movement in pens, reducing free access to forage and reducing intakes. This can be a major problem in pens where there are shy feeders or animals are poorly matched on size and there is increased bullying.
The main offender is generally cattle housed on slats. Table 1 details guideline stocking rates for different classes of animals housed on slats or straw bedding.
The recommendations are for pens where there is adequate feeding space. Where feeding space is limited and animals are fed a restricted diet or forage is supplemented with concentrates, for example, feeding space will then take priority over stocking rate and dictate the number of animals per pen.
Where animals are being fed ad-lib and feeding space is restricted (but stocking rate is sufficient), it is vitally important to maintain fresh feed in front of animals at all times.
In a situation like this, feed trough management is crucial. The volume offered should be balanced slightly above demand, so that it is not a case of fresh feed being topped up continuously on older material, resulting in feed going off.
The feeding area should also be checked daily and any spoiled material removed.
Group animals on class and size
It is important to group animals according to their category and feeding regime. Bulls, steers and heifers should be penned separately. Do not pen bulls adjacent to female stock.
Try to limit the liveweight range between cattle to a minimum (no more than 50kg to 60kg). Finishing animals, and in particular bulls, should also be grouped according to their target slaughter date.
Where feeding bulls, it is advised to keep group size below 15 animals per pen.
Group cows on condition
Grouping cows on body condition will allow feeding levels to be targeted to nutritional demand. The ideal situation is where cows can be split into three groups – cows in excessive condition that can be restricted; cows in ideal body condition and fed to maintenance; and under-fleshed cows requiring preferential treatment.
Shy feeders, older cows in the herd and first calvers will likely be in this latter group.
It is important to act early – there is little point trying to starve cows or pump cows up in the weeks approaching calving in the hope of getting cows into the required body condition.
Accounting for daily liveweight gain
It is important to note that stocking rates will change every day throughout the feeding period by animals gaining weight each day.
Take an example of a pen of 15 finishing bulls penned together on an intensive finishing diet. If each animal gains 1.5kg liveweight each day, there is 22.5kg extra liveweight in that pen each day, 157.5kg extra each week and the equivalent of an extra animal weighing over 600kg every four weeks.
A lot of animals in Ireland are housed in pens of seven to eight to suit slatted accommodation and with such a set-up, there will be the equivalent of an extra animal after eight to 10 weeks.