Abstract #T219

# T219
Increased stocking density at the feed bunk may affect the welfare and productivity of dairy cows and growth of their heifer calves.
Jessica A. Pempek*1, Maurice L. Eastridge1, Kathryn L. Proudfoot1, Gregory G. Habing1, Lohendy M. Muñoz Vargas1, Danielle N. Coleman1, 1The Ohio State University, Columbus, OH.

Overstocking the feed bunk during late-gestation has behavioral and physiological consequences, both of which negatively affect the welfare of the cow. However, it is unknown as to whether overstocking the dam may also affect the growth of the developing calf. The aim of the present study was to investigate the effect of increased stocking density at the feed bunk during different stages of the dry period on metabolic health and productivity of dairy cows, as well as the postnatal growth of their calves. One hundred twenty nonlactating Holstein dairy cows were blocked and assigned to 1 of 4 treatment groups with different stocking densities at the feed bunk (Overstocked (OS): 0.88 headlocks/cow; Understocked (US): 1.17 headlocks/cow). The 4 treatments were: OS from 60 to 1 d (OS), OS from 60 to 26 d and US from 25 to 1 d (OS-US), US from 60 to 26 d and OS from 25 to 1 d (US-OS), and US from 60 to 1 d (US) before calving. The heifer calves’ treatment reflected the treatment assignment of their dam (n = 13, 18, 16, and 11, respectively). Blood samples were obtained from the cow at −60, −30, −14, −7, and +7 d relative to calving to determine concentrations of nonesterified fatty acids (NEFA). Colostrum quantity and quality were recorded from the cow’s first milking. Calf body weight (BW) was measured once per wk through weaning at 5 wk of age. Data were analyzed using repeated measures and the Mixed model procedure of SAS (2012). NEFA concentrations were similar among treatment groups across periods (0.36, 0.42, 0.37, and 0.42 mEq/L, respectively; P > 0.05). There was a tendency for colostrum quantity to differ among treatments (7.52, 5.70, 7.03, and 8.76 kg, respectively; P = 0.11), primarily due to the difference between OS–US and US. However, there was no difference in colostrum quality (weighted Brix value of 7.24%). Using initial BW as a covariate, calf BW was similar among treatment groups (53.7, 51.9, 52.2, and 54.1 kg, respectively; P > 0.05), and there was no treatment by week interaction. In conclusion, moderate increases in stocking density at the feed bunk did not appear to compromise the metabolic status of dairy cows or the growth of their heifer calves.

Key Words: stocking density, feed bunk, dry period