Guidelines for the Management of Calves in Intensive Systems, from Birth to Weaning

In recent years, adjustments to the production costs in the dairy industry becomes crucial in light of current circumstances. There has been a continuous reduction in profit margins and increasing instability in this industry. Each stage in the production process requires maximum efficiency from both professional and economic points of view. The calf rearing stage is an integral part of the dairy business, and takes large part in determining the future quality of a dairy herd.

A simple analysis of growth rates of replacement heifers shows that the animal must double its weight within a specified period and achieve growth (in terms of shoulder’s height) of approximately 25% of a heifer’s total growth from birth to first calving. The positive correlation between shoulders’ height, skeletal growth, and milk production was already demonstrated (Shamay et al, 2005, Moalem et al, 2010) and should be taken into account.

The birth to weaning phase is crucial, because at that stage many important processes that are involved in the productive capacity of the replacement heifer occurs. For example, during this stage the calf’s digestive system is functioning as monogastric, and then it undergoes a transition to ruminant digestive tract. (It is important to emphasize that the process begins during this period but  is completed after weaning)

It should be indicated that calves are very sensitive to diseases, and up to 90% of culled replacement heifers occurs at the first 4 weeks of life. In Israel, the average mortality rate from calving up to the first 24 hours of life is about 8% and until weaning another 4% died.

In summary, this stage of growth has three main objectives; 1- Low rate of morbidity and mortality; 2- Early rumen development’ and 3- A steady growth rate. Hence, the producer must seriously consider implementing proper practices to achieve efficiently these three objectives.

The objective of this article is to review the factors that directly influence the calf growth until weaning. It is important to clarify that the present “checklist” was generated for replacement heifers reared in intensive systems, in which the calves are housed, weaned at approximately 60 days, and later on, each group (according to their age) is fed with TMR according to professional recommendations.   

The main goal of raising replacement heifers is to get the heifers to first calving, where they will be able to fully fulfill their genetic potential at low economic and environmental expenses, at proper calving weight, height, and body condition score.

 

It should be taken into account that the nutritional requirements of the dam (energy and protein) during the pre-calving stage will be increased. On the other hand, dry matter intake of the dam during the last 21 days prior to delivery, may be decreased by 30%.

In most of the cows, the energy balance will be negative at the end of gestation and during the first weeks after delivery,  which is directly connected to possible postpartum diseases, and the interval from calving until first insemination.

In reference to nutrition, the daily expected consumption during the dry period will be on average 15-16 Mcal and 1200 g of metabolizable protein. The diet density will be 1.55 Mcal/ kg DM and 14- 15% crude protein.  It should also be noted that the pre-calving diet should provide a balanced vitamin nutrition (A: 100,000 to 125,000 IU per cow per day, D: 35,000 to 40,000 IU per cow/day and vitamin E: 1200 to 2000 IU cow/day).

Other important factors:

 

Colostrum management should take into account three important factors:

 

Immediately after birth, the umbilical cord must be cleaned and disinfected

Poor sanitation and mismanagement of the calving area/pen cannot replace the umbilical cord dipping for disinfection. Both measures must be carried out.

 

Calves should be fed at least twice a day (during the first three weeks), at the same time each day, preferably in the early morning and a second time preferably in the afternoon or evening hours, regardless of times scheduled  of the milk or the replacement milk supply. In the case of supplying a third time, it is recommended to do so at night.

The third daytime supply may be necessary to provide nutrients and energy during cold weather, or for small or weak calves.

Milk consumption is calculated based on approximately 10% of the animal's live weight. Animal of 40 Kg should consume approximately 4 liters of milk/day.

The following factors should be taken into consideration:

 

Calves should be fed twice a day during the first three weeks, at the same time, each day, preferably in the early morning and a second time, preferably in the afternoon or evening hours, regardless of times scheduled of the milk or the replacement milk supply. In the case of supplying a third time, it is recommended to do it at night.

A feeding program based on the average consumption of 450-500 g of milk replacer per day should be established.

It should be taken into account that the selection of the milk replacers can directly determine the results of the calf’s growth program.

Analysis of nutritional content:

For the use of milk replacers, it is necessary to consider

Water supply to calves must be carried out, taking into account the requirements of the animals (physiological needs), without counting the water provided by the milk or milk replacer.

 

Different possibilities for dry food supply:

In extensive management systems, there is the possibility of using pastures (grazing pastures) or cut grass as a nutritional alternative. This paper does not evaluate this alternative.

It is important to note that ruminal development will occur mainly between 4-8 weeks of life and will depend on the supply of solid food. The way in which solid food is supplied must consider its influence on rumen development (promotion of the papillae growth).

Should one choose to administer starter, it should be noted, that its supply must be from the first day. If this is the chosen practice, the supply of hay will be provided only after weaning, ensuring the use of excellent quality hay.

The choice of the TMR that includes hay as one of its ingredients may:

We may consider that hay intake may limit the concentrate intake, and consequently, reduces the amount of total energy consumed (limits growth). Therefore, it is recommended to limit the amount of hay in the TMR to10-12% of the total DM.

 

Other factors to take into consideration before considering a feeding method:

To stimulate feed intake, it is recommended:

 

It is advisable to perform the removing of horns at an early age.

Objectives: Prevent injury and minimize social interference

Methods: Dehorning methods vary by age of animal and stage of horn development. 

 Can only be used in calves under two months of age:

Mechanical dehorning methods: Some of the available methods are: knife dehorning, tube, cup or spoon dehorning, Barnes or Gouger dehorning, etc.

The mechanical dehorning methods can be used on horns at any stage of development.  The dehorning system must be selected taking into account that the intervention does not cause pain or any kind of damage to the animals. For this reason, to select the optimal method for the existing conditions with your animals, we recommend consulting a veterinarian.