1.8 Management Heat Stress

1.9 Reproductive Management of Dairy Cows

1.10 Guide to Good Dairy Farming Practice

By: Mohammed Sabah2014

Ch.1 Dairy cows management

Temperature Humidity Index (THI)

Misters

Fans

Sprinkling

1.9 Reproductive Management of Dairy Cows

The main points in this chapter:

•Understanding the fertility timetable for the milking cow assists with managing reproductive procedures.

•100 day-in-calf rate and 200 day-not-in-calf rate are two good measures of reproductive performance. Submission rate and conception rate are the other two important measures.

•Nutrition is just one of many factors affecting reproduction. These factors can be categorised into their degree of difficulty for the farmer to influence.

•The key nutrition factors are feed intake, body condition and heifer live weight.

•Heat detection, length of the voluntary

Improved reproductive performance provides many benefits to farmers such as:•higher average milk yields each day – cows with poor reproductive performance will spend more of their time in late lactation, when daily milk yields are lower.•less culling of cows failing to become pregnant•fewer cows with long dry periods•reduced insemination and semen costs•heifers calving at a younger age•increased number of calves produced each year, thus providing more animals for sale or as replacements for the milking herd•more efficient feed utilisation as a result of the above benefits•more profits, less work and less worry.

Reproductive Targets

Low Culling Rate for infertility: < 5%.

Calving Interval: 365 day calving-to-calving.

Compact Calving: 90% calved in < 80 days

The main fertility management goal for dairy farmers, is to have cows and heifers conceiving at the time the farmers intends them to, so that calvings will occur according to a projected production schedule.

Reproductive Management of Dairy Cows

1. Voluntary Waiting Period

2. Pregnancy Rate on First Cycle

4. Culling Rate

Factors Driving Reproductive Performance of the Dairy Herd

Improved reproductive performance provides many benefits to farmers such as:

1- higher average milk yields each day – cows with poor reproductive performance will spend more of their time in late lactation, when daily milk yields are lower.3- less culling of cows failing to become pregnant.4- fewer cows with long dry periods.5- reduced insemination and semen costs.6- heifers calving at a younger age.7- increased number of calves produced each year, thus providing more animals for sale or as replacements for the milking herd.8- more efficient feed utilisation as a result of the above benefits.9- more profits, less work and less worry.

The ‘fertility for life’ cycle involves calf and heifer rearing, first mating, pregnancy and calving. Then for subsequent lactations, it involves matings and pregnancies, calvings and, eventually, culling. Success will require attention throughout the cycle. Basically, any management plan should answer an important question: today has everything been done to ensure high reproductive performance? From the day a calf is born, farmers control the factors influencing her future fertility, hence whether she gets in calf on time, every time. There is no simple recipe because every farm is different and will require its own plan. In Calf focuses on the key drivers of:

•calf and heifer rearing•body condition and nutrition•voluntary waiting periods of no more than 50 days•heat detection•artificial insemination (AI) technique and sire selection•bull management•cow health•heat stress management.

The optimum calving interval has been 12 to 13 months. This means that cows should get pregnant between 3 and 4 months after calving.

The voluntary waiting period (VWP) is defined as the time from calving to the start of the breeding period.

The fertility cycle can be best understood by following the recommended reproductive timetable:

•calving, with minimum difficulty•involution of uterus takes 21 days•follicular development commences 14–21 days after calving, in a well-managed cow•voluntary waiting period, or days after calving with no insemination, should not exceed 50 days•cycling occurs every 18–24 days•first insemination should be 50–80 days post-calving•pregnancy takes 282 days•dry off cow 50–60 days pre-calving•transition period to calving for 14–21 days.

For year-round calving herds, the two useful measures of reproductive performance are:

•100 day-in-calf rate. This calculates the percentage of the cows in the herd that become pregnant by 100 days after calving. It also describes how many cows will calve within about 13 months of their previous calving.

•200 day-not-in-calf rate. This calculates the percentage of cows not pregnant by 200 days after calving. Farmers want as many cows as possible to calve no more than 15–16 months after their previous calving.

Introducing 100 day-in-calf and 200 day-not-in-calf rates

There is an old saying ‘If you can’t measure it you can’t manage it’. Benchmarks make it is possible to respond when measures indicate reproductive performance can be improved and to assess whether it has improved as a result of management changes.

Voluntary waiting period (VWP)The interval that must elapse from calving until a cow is eligible to receive her first AIservice is termed the Voluntary Waiting Period (VWP). As the name implies, the duration of this interval is voluntary (i.e., a management decision) and traditionally

varies from 40 to 70 days.

For each cow in the herd, the calving interval can be subdivided into the following four intervals:

1) The voluntary waiting period (VWP), or the interval from calving until a cow is eligible to receive her first AI service;

2) The interval from the end of the VWP to first AI service;

3) The interval from first AI service until conception; and

4) The gestation period.

The time of the calving interval that is possible to influence by management is the open days. These days are determined by the voluntary waiting period (VWP) and the breeding window (BW). Missed heats are a common reason for undesirably long calving intervals. With improved heat detection rate (HDR) and conception rate (CR) via better management and improved timing of inseminations, it is possible to obtain a significantly shorter calving interval.

Effect of AI timing on Conception Rate

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Guide to good dairy farming practice

(good agricultural practice – GAP and good manufacturing practice – GMP)

Good Agricultural Practices (GAP)

The suggested GAP for animal health are set out under the following headings:1.1. Prevent entry of disease onto the farm.1.2. Have an effective herd health/disease management programme in place.1.3. Use veterinary drugs as prescribed by veterinarians or as specified on the label 1.4. Train all people appropriately.

The suggested GAP for milking hygiene are set out under the following headings:• Ensure milking routines do not injure cows or introduce contaminants in milk• Ensure milking is carried out under hygienic conditions• Ensure milk is handled properly after milking

The suggested GAPs are set out under the following headings:• Ensure animal feed and water are of adequate quality.• Control storage conditions of feed• Ensure the traceability of feedstuffs bought off farm

Good Agricultural Practices (GAP) for animal welfare. They are set out to reflect the five basic freedoms:• Ensure animals are free from thirst, hunger and malnutrition • Ensure animals are free from discomfort• Ensure animals are free from pain, injury and disease• Ensure animals are free from fear• Ensure animals can engage in relatively normal patterns of animal behaviour

The suggested Good Agricultural Practices for the Environment are set out under the following headings:• Have an appropriate waste management system.• Ensure dairy farming practices do not have an adverse impact on the local environment