Feeding Kelp to Organic Dairy Calves

Brad Heins, Assistant Professor of Dairy

Numerous organic dairy producers use kelp in rations to feed organic dairy calves, heifers, and milking cows, and it is widely used and thought to improve animal health.  Organic dairy producers have reported that kelp may lower somatic cell count, reduce pasture-fly pressure, and improve body condition of dairy cattle. Kelp encompasses a variety of seaweed or genera that grow in the shallow areas of oceans, and most kelp has been harvested from the North Atlantic Ocean.

Kelp is a rich source of various vitamins as well as iodine, calcium, copper, and other trace minerals. There is very little research that has evaluated the use of kelp in organic dairy rations for calves, and we wanted to evaluate the effect of feeding kelp on growth and profitability of group-fed calves fed once per day in an organic production system.

Data was collected for 115 organic Holstein and crossbred dairy heifer calves from 2 calving seasons (fall 2012 or spring 2013).  Heifer calves were assigned to 1 of 3 treatment groups of 10 calves per super hutch based on birth order. Treatment groups were (1) control calf starter (NoKelp), (2) calf starter plus 2 oz of kelp per calf daily (K2), or (3) calf starter plus 4 oz of kelp per calf daily (K4).  All calves were weaned at 60 days of age. 

Results for pre-weaning and early post-weaning body measurements for the calf starter ration groups are in Table .  The calf groups were not different from each other for birth weight, weaning weight, and average daily gain during the pre-weaning phase of growth. However, the NoKelp calf groups had greater weaning hip height compared with kelp starter groups. The NoKelp calves had greater 90-d body weight and average daily gain compared with the kelp-starter-ration calves. 


Table 1: Results for group-fed organic dairy calves by starter group
No Kelp2 oz. Kelp/day4 oz. Kelp/day
Birth weight (lb)85.983.180.2
Weaning weight (lb)181.2173.7177.9
Weaning hip weight (inches)37.135.7*35.9*
Average daily gain to weaning (lb/d)1.481.371.39
90-d weight (lb)251.5238.5*233.7*
Average daily gain, birth to 90 days (lb/d)1.721.61*1.57*
Average cost $/gain (lb)1.671.81*1.89*

n=number calves.  *P<0.05 for contrast of difference from calves fed no kelp.  Heins and Chester-Jones, 2015, Professional Animal Scientist 31:368-374

When all calves were compared at 90 days of age, the NoKelp calves had significant advantages for cost per pound of gain. The average cost per pound of gain for the NoKelp ($1.67/lb) calves tended to be lower than the K2 ($1.81/lb) and K4 ($1.89/lb) calves combined.

Although kelp is promoted in the organic dairy industry to improve animal health, there were no differences in calf groups. Overall health was good and health costs were low for all groups. It is not known if calves that are subject to more sickness than the calves in this study would possibly respond more favorably to supplementation with kelp. 

Quite possibly, calves fed kelp did not consume enough calf starter because of their dislike of the taste of kelp in the rations. Based on the results of this study, including kelp in dairy calf starter rations may not be economically justified because of the high cost of kelp and reduced performance of calves.