A heifer is a female cow that is very young usually over a year old but has not been calved. When heifers are managed properly, the cow is able to get to puberty early, increases the weaning rates while decreasing the rates of mortalities. A good heifer management system also ensures that the reproductive function of the cow is carried out properly without having any problems and this is very important to ensure the overall performance of the breeding herd.
To develop a very good, safe, and healthy foundation for the growth of a dairy herd, well-grown and properly managed heifers are critical. For this reason, dairy farmers should be very interested in factors that affect and contribute to the growth, development, and future productivity of their heifers. Taking note of all these will result in the farmers providing the best and optimum living conditions for these animals.
A good heifer management program or system is very important because first, heifers usually require a greater nutritional necessity than cows as they are attempting to reproduce and grow simultaneously. Another reason is that except if mating is controlled properly, a large number of heifers can have their initial lactation during a dry season because puberty can be reached at any time and only heifers that have been well-managed will be able to conceive during their initial lactation.
Management Tips for A Good Heifer
The factors mentioned above usually cause low calf production and leads to high mortality rates in heifers. Also, inappropriate timing of initial lactation, coupled with poor nutrition, may permanently stunt heifers, thus reducing their turnoff value.
For a heifer system to be effective and work properly to have the desired outcome, the following components are very important:
- Heifer control (heifer paddocks)
- Desired critical mating weight (CMW)
- Mating management
- Nutritional management
- Management of weaning
- Selection and culling
- Disease control
- Genetic improvement
- Vaccination of Heifers.
#1. Heifer Control
Many farmers usually decide to allocate a particular amount of space for female heifers to graze. This often involves a minimum of 2 secure paddocks with one paddock being double the size of the other paddock. The smaller paddock is for weaners. At 18 months, these weaners are transferred to the larger one.
Then finally, when the heifers get to around 3 and a half years of age, they should be taken or transferred to a mature breeder paddock. If further paddocks are available, there are options to segregate heifers on age or management needs such as pregnant and non-pregnant heifers or turnoff and breeding heifers.
#2. Desired Critical Mating Weight (CMW)
When farmers have an idea or know the critical mating weight they desire, it assists them to better manage nutrition and growth to achieve high pregnancy rates. Critical mating weight (CMW) is the minimum weight at which heifers should be mated to achieve a high pregnancy rate when first joined. Weight is one of the most significant influences over the time at which heifers reach puberty and begin to cycle.
CMW is different among different types of cows and the average weight of mature cows. To be very effective, CMW is usually based on the
- average and variation in weight at puberty; average weight at puberty is typically two-thirds of mature cow weight and variation is high
- time of heifer selection
- period of mating
- the time is taken for healthy cycling heifers to conceive
- the target pregnancy rate
- sire effects.
#3. Mating management
For mating, it is usually recommended that mating should be done when lactation will be during the wet season. This ensures that the chances of the heifers successfully rearing calves and of re-conceiving during the first or second lactation is very high. Heifers that lactate during the wet season are much easier and cheaper to manage than those that calves out of season.
Ideally, as soon as the females began to cycle, a joining period spanning three cycles or nine weeks is required to achieve a 95% pregnancy rate. About 90% will get pregnant within a couple of cycles and 95% within three cycles. More so, a bull ratio of 2–2.5% is recommended. Bulls should pass a Bull Breeding and Soundness Examination or BBSE. This is very important especially if only one single male is being used.
#4. Nutritional management
Nutritional management is important so that heifers can reach the desired critical mating weight, to ensure their bodies are in optimal shape for calving, and to maintain adequate body condition and growth during their first lactation.
Weaner nutrition is critical as poor growth in this period can increase weight at puberty, thus reducing early lifetime fertility. A good simple approach is to manage nutrition to keep heifers well above maintenance so the skeleton keeps growing. For more information see Weaning – a critical component of herd management and Weaner supplements.
Heifers must have access to adequate pasture, water, and supplementation to keep them in the best possible condition. Spike feeding has been shown to increase the rate of conception following calving by an average of 15%. Feeding should be for a minimum of 50 days, starting 6-8 weeks before calving is due to commence. For more information see Spike feeding. Wet season supplements may be necessary to correct major mineral deficiencies, which can impact significantly on feed intake, growth rates, and fertility.
#5. Management of weaning
Weaning removes the stress of lactation and may reduce further loss of body weight for lactating first calf heifers as it significantly alters the nutritional requirements of a heifer (or breeder). The extra energy and protein requirements needed for lactation are removed. The major benefits of good weaning management are better cow condition next season, more conceptions during the next lactation, more calves the year after, and higher steer sales in the future. It makes sense then that weaning is a critical component of a heifer (and breeder) management program.
Calves from heifers should be weaned first and all calves should be weaned in the first round. Weaning calves earlier than normal should increase the chances of heifers cycling and conceiving following calving. However, in certain situations, heifers may require supplementation to commence cycling again as discussed above. Depending upon better nutrition the well-grown and well-developed heifer of Taurus, crossbred, and zebu cattle calving age would be 2, 2.5, and 3 to 3.5 years age respectively
#6. Selection and Culling of Heifers.
Many producers over-mate heifers and then remove/cull surplus heifers based on a pregnancy test. Empty heifers that have had ample opportunity to conceive are sub-fertile or infertile and should be removed as they are not profitable themselves, and their genetics are removed from the herd.
Depending on the overall results and replacement numbers required those heifers that will calve late (as a result of late puberty) can be culled as well (or identified or segregated for future reference). Other traits that should be considered when culling include temperament, growth rate, ability to hold condition, and physical defects.
Heifer having anatomical defects, bad disposition, and poor growth and late-maturing should be culled. Calves from the parentage of low productivity, longer calving period, and maturing late must be removed.
#7. Disease control
Parasites need to be effectively controlled by deworming heifers since Worms interfere with the absorption of food nutrients, feed on body tissues, suck blood and consequently interfere with the hosts, growth, reduce vitality and resistance. This makes it very important for these animals to be dewormed every 4 to 6 months. Drugs such as Anthelmintics can be used against Gastrointestinal Worms, Lung Worms, Tape Worms, and Flukes of Cattle
For ectoparasites such as lice and ticks which are picked up easily by the cattle or heifer when grazing outdoors, spraying with insecticides like 1 percent marathon spray is very effective. Grounds nearby and around sheds should be sprayed with DDT. Also, regular grooming of heifers is helpful not only in the detection of such problems but also in making animals docile.
8. Genetic improvement
Both age of puberty and weight at puberty is highly heritable. This means genetic progress can be made in these traits. Sire-effects alone can account for variations of at least 100kg in weight of puberty of female puberty. Additionally, heifers that conceive early in the joining period can be identified and recorded for future reference.
It has been discovered that there is a genetic relationship between the scrotal size in bulls and the age of puberty in their daughters. Bulls of above-average scrotal sizes should be selected and this will assist in making genetic progress.
For heifers that are reared under the grazing system, no extra exercise is needed, but for those who are kept in-door, they need little open area (run-out) with the shed where they will have freedom of movement to get sufficient exercise. Exercise will remove stiffness in their limbs, keep them thrifty, growing, and maintain a normal appetite.
10. Vaccination of Heifers
The primary recommendation for vibriosis control is to use vaccinated bulls. Where the disease is rampant consider vaccinating heifers prior to mating but be careful to weigh up the cost-benefit given the cost of vibriosis vaccinations. With pestivirus, existing levels of herd immunity can substantially influence control strategies. It is suggested that producers take advice from their cattle vet when considering whether vaccinations should be used prior to mating
At 6 months of age, heifers should be vaccinated for foot and mouth, T.B. and rinderpest using polyvalent tissue culture vaccine, B.C.G. tissue culture vaccine respectively. Older heifers should be vaccinated for Anthrax, Black Quarter (BQ), and Hemorrhagic septicemia using spore vaccine, formally killed vaccine, and oil adjuvant vaccine respectively with a few days interval in between prior to commencement of rainy season every year. Proper sanitation and hygiene measures will help in the prevention of most of the infections.