Raising heifers is expensive! Evaluations from Mecklenburg-Western Pomerania show breeding costs of around 2.20 euros per animal per day. This means: The older the heifers calve the first time, the more expensive the breeding. Depending on the farm, there are large differences in the average age at first calving (EA) of heifers. With intensive breeding, an EKA of around 22 months is very possible and can thus save breeding costs.
But: If heifers start their first lactation very young, this can also have a negative impact on milk yield. Because the more energy they need during breastfeeding for their physical development, the less energy is left for milk production. Recording the weight and comparing young and old cows can help dairy farmers find the right EKA for their own herd.
1. Keep an eye on the physical development
To accurately monitor the development of young animals, it is important to record body weight. As a starting point, a body weight (BW) of 400 kg or an age of 15 months is a guideline value for the first insemination for Holsteins. However, it is better to set target values that match your own crew. The “adult cows” in a herd serve as the basis for this.
A mature cow means a fully grown, healthy cow in the 4th lactation on the 80th to 200th day of lactation. It is considered to be representative or the target weight for the majority of the herd. The weight of this cow can vary enormously depending on the herd. Tip: Weigh ten cows together on a trailer and calculate the average.
The target weights are based on the old cows:
- 55% of the adult cow’s body weight at the 1st insemination
- 82% of the adult cow’s body weight after the 1st calving
For example, if the adult cows in a herd weigh 700 kg on average, young cattle with a body weight of around 385 kg can be inseminated for the first time. For cows with a body weight of 750 kg, you should at least wait until a body weight of 413 kg (see table). The earlier young cattle reach their target weight, the shorter and correspondingly cheaper the rearing is. If they are inseminated before they reach their target weight, they will have to “grow back” later, which can be reflected in a lower milk yield.
2. Compare peak power
Whether the heifer invests a lot of energy in her own development during the first lactation is reflected not only in her body weight, but also in her peak performance (Table 2). The expected peak performance of a heifer is also based on the adult cows in a herd. The 80% mark is the rough target value. In maximum lactation, heifers should achieve about 80% of the milk yield of their older stablemates. The performance level of the crew is irrelevant.
The cows in a herd (3rd + 4th lactation) weigh an average of 700 kg and produce 45 kg of milk at peak. The heifers weigh 500 kg and produce 32 kg of milk at peak.
Body weight: 500 kg / 700 kg x 100 = 71%
Milk yield: 31 kg / 45 kg x 100 = 69%
To reach the target of 80%, the heifers would have to weigh around 560kg and produce 36kg of milk. Here are reserves that they invest in their growth.
Loss of milk price:
One kilogram of colostrum means approximately 200 kg of milk in 305 lactation days. In this example, 5 kg of peak output is missing, so the unrealized milk quantity is 1,000 kg (5 x 200 kg). With a milk price of 40 cents/kg ECM and feed costs of 20 cents/kg TS (1 kg TS = 2.2 kg ECM, ie 9 cents feed cost/kg ECM), the following milk price loss results: 40 cents minus 9 cents = 31 Cents /kg ECM or 310 euros per animals and lactation.
3. Find the right EKA
Conclusion: The EKA of heifers can be reflected in the breeding costs as well as in the milk price and should be adapted individually to the respective herd. If target weights are considered during breeding, the heifer is sufficiently developed at first calving to reach her performance potential. Otherwise, physical development can cost milk. Danger: For other dairy breeds, guideline values and the ratio may vary considerably. Nevertheless, it is advisable to question the development and EKA.
It is crucial to find the right path for your own business and to keep an eye on the numbers. Dairy farmers should
- Record weights (at least during breeding),
- know target weights (adult cow),
- Compare lactation curves (MLP report),
- regularly analyze the relationship between body mass and performance between young and old cows.
1. Holstein farm in Mecklenburg-Vorpommern; driving weight
| over 2,000 cows, 11,500 kg of milk
| Age at first calving: 21.4 months
| Heifers: 570 kg body weight, 36 kg maximum production
| Cows: 780 kg body weight, 50 kg maximum performance
| Ratio: 73% at BW and 70% at peak power
2. Holstein operation in Mecklenburg-Western Pomerania; driving weight
| 1,300 cows
| Age at first calving: 24 months
| Heifers: 530 kg body weight, 30 kg maximum performance
| Cows: 750 kg body weight, 45 kg maximum performance
| Ratio: 71% at BW and 67% at peak power
3. Holstein farm in Sauerland (NRW); Weight in the milking robot
| 270 cows, 11,374 kg of milk
| Age at first calving: 24.8 months
| Heifers: 9,845 kg lactation production, 35 kg peak production, 678 kg body weight
| Cows: 12,396 kg lactation production, 50 kg peak production, 775 kg body weight
| Ratio: 87% at BW and 70% at peak power
4. Fleckvieh farm, Upper Swabia (BW); Weight in the milking robot
| 91 cows, 8,896 kg of milk
| Age at first calving: 26.1 months
| Average weight of all cows: 728 kg bw
| Maximum weight: 954 kg
| Minimum weight: 550 kg KGW
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