Summary of research # 870-1536-09 presented by Gaby Adin to the Milk Israeli Council.

"Effect of weaning age (8 vs. 4 weeks) on dairy calf growth and health"

G. Adin, Extension Service, Ministry of Agriculture, Israel.

 

Introduction:

 The sharp rise in the prices of milk powders in the world during 2008 was a result of the increase in the consumption of the milk mainly in Southeast Asia. An extensive review in United States situated 60% of dairy farms using milk replacers in the wide variety of qualities. The age at which you decide to wean a dairy calf will have a definite impact on the cost of raising that calf. Often the actual total cost for raising a calf will not completely determine the growth and resulting age and weight at calving. Weaning age can have a large impact on calf raising costs. It has been a topic of recent research at Penn State that studied the impact of weaning calves at 3, 4, 5, or 6 weeks of age. Calves were monitored until 8 weeks of age for health and growth impacts through the post weaning period, and they found that calves weaned at 4, 5, or 6 weeks of age were exactly the same through 8 weeks of age in terms of health, growth (weight and height), and feed efficiency. The primary difference between groups was in the rearing cost. Calves weaned earlier had lower rearing costs due to reduced labor and slightly lower feed costs.
The main purpose of this work was to test if there are physiological differences in the development of calves weaned at 4 or 8 weeks, and if there are differences in the raising costs.

Materials and methods:

The experiment took care in "Hanegev" dairy farm Kibbutz Gvulot, on two groups of 53 calves each (all females) divided according to BW at birth. The control group was feed with a milk supplement protocol based on 33 kg dm in 60 days, 2 feeding/day until 21 days and one until weaning. The milk replacer contained 23.7% CP and 15.5% Fat (DM basis). All calves had free access to starter (19.5% CP DM basis). The experimental group was fed milk replacement until free starter consumption was 900 grams/day (following: the day when the experiment begins). The parameters examined were: BW at birth, when the experiment begins and at 60 days, DMI (starter) when the experiments begin and at 60 days, and health index.

Results:

 In both groups calves started eating at least 900 grams of concentrate at 38 day. There was no difference in BW at birth, when the experiment begin and at 60 days (37.6 vs. 38.1 kg; 51.3 vs. 51.7 kg; 73.7 vs. 73.0 kg in the control and experimental group accordingly), also the weight daily increase 334 vs. 336 gram and 946 vs. 930 gram from calving until experiment begins and from when the experiment begins until days 60 days between control and experimental group accordingly.
No difference in DMI when the experiment begins (979 vs. 1036 grams/day), but the average DMI from concentrate between then until 60 days was significantly higher in the experimental group (1915 vs. 1176 grams).

Conclusions:

Weaning calves at 38 or 60 days hade similar average daily gains or any health parameter. In both treatments calves nearly doubled their birth weight by 8 weeks of age, and this is a good parameter in any calf feeding system. Early weaned calf's starter intake compensated the protein and energy demands.
Early weaned calves can therefore require less feed costs (32$) and less farm labor (14$).
In the future we analyze data according to days to first AI, conception rate, weight increase until first calving and milk yield on first lactation.