FROM THE FARM REPORT: FUTURE IMPACTS OF PRE-WEANING NUTRITION

There appears to be an increasing focus on the pre-weaning period due to its association with subsequent milk production, and more recently, longevity within the herd. A 2025 Journal of Dairy Science article by Leal et al. focused on the long-term effects of pre-weaning nutrient supply on lactation performance and survival in the herd. Eighty-six Holstein heifer calves were enrolled on the second day of life and followed up to their fifth lactation. Calves were assigned to one of the two milk replacer (MR) feeding strategies, consisting of differing metabolizable energy (ME) levels and two volumes of MR fed daily. The elevated treatment provided 5.4 Mcal of ME per day at a feeding rate of 8 L of MR per day. Whereas the restricted treatment provided 2.7 Mcal of ME per day at a feeding rate of 4 liters of MR per day. From days 42 to 49 of age, MR allowance was decreased by 50% and calves were fully weaned on day 50. Following weaning all animals were managed under the same conditions.

During the pre-weaning phase, heifers on the elevated treatment exhibited a higher average daily gain (ADG; 0.79 vs. 0.49 kg/d; 1.74 vs. 1.08 lb/d) and an increased body weight at 70 days of age (94 vs. 85 kg; 207 vs. 187 lb).

In the first lactation the cows on the elevated treatment had an increased dry matter intake (DMI) compared to those on the restricted treatment. Although overall milk yield and protein content was the same regardless of treatment, milk fat yield and percentage increased for those on the elevated treatment. Furthermore, feed efficiency as the ratio of Fat and Protein Corrected Milk (FPCM) was lower in the elevated versus restricted treatments.

In contrast, during the second lactation the elevated treatment had an increased FPCM and greater feed efficiency. The authors suggested that these changes in productivity could be due to changes in metabolism early in life. Through a pathways enrichment analysis, they found several metabolic pathways were affected by nutrient intake. These pathways included the TCA cycle, fatty acid metabolism, purine metabolism, guanidino and acetamido metabolism, and sphingosine and pyrimidine metabolism.

Moving beyond productivity of the animal, there were differences in longevity between treatments. Compared to the restricted treatment cows on the elevated treatment during pre-weaning had a lower risk of leaving the herd across lactations. By the third, fourth and fifth lactation, the risk of culling was reduced by half for the cows on the elevated treatment. These results suggest that early-life nutritional programming impact the future productivity and longevity of the animal.

— Victoria Blaney

vblaney@whminer.com