agricultural production guidelines
m
Veld in KwaZulu-Natal
Co-ordinated Extension KwaZulu-Natal Veld 2.7 1999
HERD GROUPINGS
D M Gammon
Agric. Foods (Pvt) Ltd, P O Box 559, Bulawayo, Zimbabwe
Animal Handling and
Management
Breeding Management
Efficiency of Supplementary
Feeding
Preference Grazing
Herd Appearance
Veld Management
Examples of Herd Groupings
INTRODUCTION
The way in which animals are grouped into herds has an important effect on their management, nutrition and performance, and on the management of the veld on which they run. The most important factors to consider in deciding on herd groupings are discussed below.
ANIMAL HANDLING AND MANAGEMENT
When cattle of widely differing ages and different sexes are mixed together, sorting for different operations, such as identification, castration, dehorning, inocul-ation, dosing and weighing, is more difficult and young animals are more likely to be injured. The bigger the herd the greater the problem and the longer the time the whole herd will have to spend unproductively in kraals. This will result in depressed performance.
Ideally, herds should consist of a single age group and sex, although the number of camps available might not permit this. The number in a herd should be such that the animals do not have to spend more than approximately 2 hours in the kraals for routine handling operations. Based on this criterion, the maximum number in a herd will depend partly on the efficiency of the handling facilities. With efficient facilities and good handling, cow herds of up to 250 or more can be handled satisfactorily. However, during the lactation period, herds of 150 cows or less are preferable. Young stock can be run satisfactorily in herds of up to approximately 400 head, but smaller herds are preferable.
The first requirement in breeding management is to isolate bulls when they are not with the breeding herds. Bulls should be grouped on their own in a set of special small camps, but if this is not possible they could be grouped with older steers, if there is such a group.
Breeding heifers should be run separately from cows, for an earlier and shorter breeding season, and should be mated to virgin bulls (to prevent injury, reduce spread of disease and to evaluate bulls).
Cull cows rearing their last calves are another group which need to be separated during the breeding season. Usually they can be most conveniently isolated from the bulls by pooling them with the young heifers.
If crossbreeding is practiced, specific divisions of the breeding herd are necessary in order to mate cows to the appropriate bull breed. Where sire identity is necessary, as in pedigree breeding and progeny testing, single-sire herds are necessary during the breeding season. However, the possible advantages of crossbreeding and single-sire herds must be weighed up against the disadvantages of having more herds and the restrictions that this places on veld management.
EFFICIENCY OF SUPPLEMENTARY FEEDING
Different classes of animals differ in their feed requirements, and unless they are separated they cannot be fed efficiently according to their requirements. Furthermore, when animals of different ages and sizes are fed together, heavier animals tend to dominate the younger, lighter animals, so that while the needs of the latter are usually greater, they actually obtain less feed. For example, it was found that when heifers were wintered with mature cows with an adequate allocation per head of supplement, the heifers lost 11 kg, while a similar group of heifers run on their own, with the same allocation of supplement, gained 20 kg. Similar social dominance effects are observed between 4 to 5 year old cows and cows over 5 years old. However, these effects do not appear to be as important between 2 and 3 year old heifers, or between weaners and yearlings.
As far as possible, where competition for supplementary feed is likely, heifers should be separated from mature cows, and, ideally, younger and older cows should be in separate herds. If mixing of age groups is necessary, it is preferable to mix young age groups with one another such as weaners and yearlings, or yearlings and 2 year olds, or 2 and 3 year olds, rather than with older age groups.
Separating groups with different feed requirements is also important where grazing of varying quality is available. The nutritional requirements of first and second calvers are greater than those of mature cows, and their performance is affected more by the quality of the grazing than is that of mature cows. Separation of these younger groups, and allocation to them of the better veld, can improve calving percentages and weaning mass. Alternatively, separation of groups with higher requirements, such as young cows, or steers being finished on the veld, and running them ahead of less demanding stock in a leader and follower system, also may be beneficial.
A herd which is uniform in terms of size, type and condition creates a good impression. This is important in selling stock and can contribute to the owner's pride and satisfaction and consequently his success.
From the point of view of animal management and performance, a large number of well sorted, small herds is desirable. However, in order to apply good veld management it is desirable to have approximately four or more camps per herd. In the long term, what is good for veld condition and veld productivity, will be good for animal production, and conversely, if the veld deteriorates through poor management, animal production will also deteriorate. It is therefore necessary to make some compromise between the optimum herd groupings and the maximum number of herds that can be run to allow good veld management.
It is usually necessary to consider herd groupings specifically for the breeding season, the remainder of summer, and the winter supplementary feeding season. For each of these periods all the classes of stock, that it might be desirable to separate, should be listed. Decisions are then made as to which classes to pool, in order to reduce the number of groups to that which will enable good veld management with the number of camps that are available, or could be made available with additional development.
Tables 1, 2 and 3 indicate the main classes of stock to be considered at the different periods of the year. All classes up to 3 year olds are included, but the older age groups would not be present if animals were marketed younger. The headings A, B, C, etc. indicate progressively increasing degrees of pooling to produce fewer groups. These are intended to serve only as
examples. The priorities as to which classes should be kept separate and how best to pool different classes to produce the desired number of groups will vary on different farms. Adjustments also have to be made to the numbers of animals in the groups to fit them to the grazing capacity of the available camps.
During the breeding season (Table 1), it is necessary to first consider which groups of breeding stock should be bulled separately. Situation A could be applicable where there is no limitation imposed by the number of camps available, or, in the case of large cattle holdings, where the numbers of head involved justify the subdivisions of all classes. On larger holdings further subdivision of each class may be desirable to ensure that the numbers per group are not excessive. If specific matings are required (e.g. cross-breeding or single-sire mating) additional breeding herds would be necessary. Situations B to G indicate ways in which groups could be combined as the number of camps available is progressively more restricted.
Table 1. Numbers in the Table refer to stock classes allocated to the same group.
Class of stock
Decreasing number of camps
A
B
C
D
E
F
G
Mature cows + calves + bulls
Young cows + calves + bulls
Heifers + bulls
Cull cows + calves (not bulled)
Heifers 3 years surplus
Heifers 2 years surplus
Heifers 1 year
Steers 1 year
Steers 2 years
Steers 3 years
1
2
3
4
5
6
7
8
9
10
1
2
3
4
4
5
5
6
7
8
1
2
3
4
4
5
5
6
6
7
1
1
2
3
3
4
4
5
5
6
1
1
2
2
3
3
4
4
5
5
1
1
2
2
3
3
3
3
4
4
1
1
1
1
2
2
2
2
3
3
Table 2. Examples of herd groupings during the non-breeding period of summer with decreasing numbers of available camps (A ) G; refer to text for explanation of symbols). Numbers in the Table refer to stock classes allocated to the same group.
|
Class of stock |
Decreasing number of camps |
||||||
|
A |
B |
C |
D |
E |
F |
G |
|
|
Mature cows and calves (bulled) Young cows + calves Young cows + calves (bulled) Heifers (bulled) Heifers 3 years surplus Heifers 2 years surplus Heifers 1 year Steers 1 year Steers 2 years Steers 3 years Bulls |
1 2 3 4 5 6 7 8 9 10 11 |
1 1 2 3 3 4 5 6 7 8 9 |
1 1 2 3 3 4 5 5 6 7 8 |
1 1 2 3 3 4 4 5 5 6 7 |
1 1 2 2 3 3 4 4 5 5 6 |
1 1 1 1 2 2 3 3 4 4 5 |
1 1 1 1 2 2 2 2 3 3 4 |
Table 3. Examples of herd groupings during the winter supplementary feeding period with decreasing numbers of available camps (A ) G; refer to text for explanation of symbols). Numbers in the Table refer to stock classes allocated to the same group.
| Class of stock | Decreasing number of camps | ||||
|
A |
B |
C |
D |
E |
|
|
Mature cows (pregnant/lactating) Young cows (pregnant/lactating) Heifers (pregnant/lactating) Empty cows and heifers Heifers 2.5 years surplus Heifers 1.5 years Weaner heifers Weaner steers Steers 1.5 years Steers 2.5 years Bulls |
1 2 3 4 5 6 7 8 9 10 11 |
1 2 3 4 4 5 6 6 7 8 9 |
1 2 2 3 3 4 5 5 6 7 8 |
1 2 2 3 3 4 4 5 5 6 7 |
1 2 2 3 3 3 4 4 5 5 6 |
During the non-breeding period of summer, the most important considerations are the size and composition of herds for ease of handling, and possibly provision of
preference grazing for groups such as first calvers and steers due for marketing. Table 2 gives examples of how the different classes could be grouped during this period to fit the number of available camps. Class priorities and numbers in different classes will vary in different circumstances and give rise to different preferences for grouping.
During the winter supplementary feeding period, animals should be grouped so that they can be supplemented according to their requirements and so that social dominance effects are minimised and, as far as possible, all animals receive their share of supplement. Table 3 gives examples of how animals may be grouped at this time to form progressively fewer herds. However, when grass is dormant there is no need to rotate animals, so there should be sufficient camps available to accommodate all groups with different nutritional needs, or which need to be separated to avoid dominance. If there are ample camps, or if animals are wintered in pens, they can be divided into all the different classes, and further divided according to mass variation and target masses within classes, in order to make the most efficient use of feed.