Knowing the time of calving is of great importance in livestock farming, especially in dairy farming. Because production and reproduction, as well as animal welfare, workload and economic success are all closely related to it.

In this blog post, we’ll take a closer look at signs and phases of calving and tell you more about the importance of regular monitoring around the calving period. The detection of the onset of calving by the smaXtec system has many advantages, as we will explain in the following.

Signs and phases of calving

A cow is pregnant for about 280 days. Estrogen levels rise two to three weeks before calving. This already leads to various physiological changes:
• Loosening of the ligaments in the pelvic area
• Redness and swelling of the soft birth path
• Increased mucus secretion of the birth path and possibly leakage of a viscous mucus thread from the vagina
• Enlargement of the udder, especially in heifers [1]

Further signs occur within 48 hours before the onset of calving:
• Clearly felt, and visible collapse of the pelvic bands
• Swelling of the labia and cervical mucus
• Conversion of the aqueous, honey-like secretion of the mammary gland to colostrum (beestings)
• Milk letdown
• Restlessness
• Body temperature drops by 0.5 – 1 degree [1] (can only be evaluated after regular measurements, evaluation occurs automatically when using smaXtec Boluses)

Calving can basically be divided into five phases:

1. The preparation phase
In this stage of the calving the signs are not yet very strong, but suggestive in their entirety. Signs of birth include sunken pelvic ligaments, glossy teats, dripping milk and red vulva with tough mucus.

2. The opening phase (6 to 16 hours)
During this period, the inner cervix opens, and the water and mucous membranes enter the cervix. The first light contractions and disturbances can be observed. In this phase, it is important to leave the cow alone so as not to interrupt the natural process.

3. The expansion phase (1 to 6 hours)
In this phase, the birth canal expands. Calving is a continuous process that can take as long as 1 to 3 hours (from the point of bubble rupture of the membranes to the head breaking through) for cows and even 4 to 6 hours for heifers.

4. The expulsion phase (5 to 15 minutes)
This phase begins with the head or pelvis moving through the mother’s vulva, which takes approximately 5 to 10 minutes.

5. The afterbirth phase (6 to 12 hours)
In the afterbirth phase, the remaining amniotic fluid and the afterbirth come away. If this does not happen within 12 hours, one speaks of post-natal problems. [2] Post-natal problems can lead to inflammation and to fertility disorders.

Ideally, a cow can give birth to her calf without help. Unfortunately, an ideal case does not always occur. If complications occur during calving, both the suckler cow and the calf can suffer serious consequences – from post-natal problems and uterine infections to weak calves and death of cow and calf. Only a regulated and systematic birth process can lay the foundation for a good start for the mother cow as well as the calf, as well as the success of the business. [2]

Regular monitoring of the onset of calving – so much easier thanks to smaXtec

Continuous and regular monitoring of the calving process is of great importance in enabling the farmer to closely follow the stages of calving and quickly identify and correct any signs of complications.

If the farmer recognizes clear signs of the onset of calving, the cow should be placed in a separate calving box and be observed as inconspicuously as possible. Here it is important to look after the cow – checks should be performed every 30 minutes during the day and every 3 to 4 hours at night.

If several cows on a farm are due to calve around the same time, this means an enormous amount of work – both day and night.
In this critical phase, the smaXtec system is your ideal companion! Different sources, e.g. Streyl et al., 2011, Gasteiner et al., 2016, show that decreasing temperature in the near-to-birth period means that calving is going to start soon. smaXtec Boluses continuously measure the body temperature of the animals. The system sends a calving alert up to 36 hours before calving if the animal is in the so-called calving window (14 days before or after the expected calving date).

A study by the University of Göttingen has shown that most of the alerts are issued between 6 and 20 hours before calving. [4]
This allows farmers to take all necessary measures to ensure a problem-free birth at an early stage. They can take their animals to a separate calving box, administer calcium boli to prevent milk fever, and assist the cow as needed at the right moment.

By taking the right action at the right time, it is possible to reduce stillbirth rates, the number of post-natal problems and uterine infections, as well as shorten the time between calvings.
In addition, you are able to detect premature births because your animals are continuously monitored with smaXtec.

Preventing problems with calving

Only a calving without complications allows calves a trouble-free start in life and allows the cow to have a healthy and powerful start to lactation. [3] One calf per year and cow means a satisfactory business result. The calf loss rate should be less than 5 %.

To avoid such losses, attention needs to be paid to a few basic aspects.

Set up calving area / calving box
• Box should not also serve as a sick bay at the same time
• Minimum of four places per 100 cows
• Twelve square meters minimum size
• Visual contact with other animals of the herd should be ensured
• Soft, sure-footed and dry lying surface; daily refill of ten to twelve kilograms of straw per cow [3]

Optimal support for the cow
• Exact knowledge of birth process and phase
• Observation of the cow
• Do not intervene too early
• Pay attention to cleanliness [3]

• First the calf, then the cow!
• Massage the calf’s mucus out of the airways and stimulate breathing
• Drying with straw, take proper care of umbilicus stump
• “Energy drinks” and tasty food for the mother cow
• Fresh water supply, clean and ruminant-friendly feed trough
• Follow-up of the cow

How the smaXtec system detects calving

As shown in the example curve, calving detection is based on the significant temperature drop (blue curve) before calving. As mentioned above, the alarm is generated up to 36 hours before the actual calving.

In the example graph, you can see that a notification was sent to the farmer at 11:00 am on September 18th. Thanks to early detection, it was possible for the farmer to separate the mother cow and bring her into a calving box, take all necessary precautions and thus guarantee a trouble-free birth.

A few hours later the cow gave birth to a healthy calf. The continuous temperature measurement can quickly detect signs of paresis (milk fever). Reduced body temperature and decreased activity are typical signs of metabolic disease.


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[4] Bongardt, Judith: Validierung des smaXtec-Systems zur Brunsterkennung, Universität Göttingen