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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Publications at this Location » Publication #412777
Research Project: Improving Sustainability of Dairy and Forage Production Systems for the Upper Midwest

Location: Environmentally Integrated Dairy Management Research

Title: Pasture-raising heifers reduced fat deposition compared to confinement heifers at similar bodyweights

Author
item CAMISA NOVA, CARLOS - University Of Wisconsin
item Jaramillo, David
item LIMA, LAIS - University Of Florida
item Akins, Matthew
item Kalscheur, Kenneth

Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/3/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Body composition of prepubertal dairy heifers can impact lactation performance and health. Information regarding body composition of heifers raised under different conditions is limited. Thus, this study evaluated the effects of rearing prepubertal dairy heifers on pasture or in confinement on body composition and growth. Holstein heifers (n=63; 5.2 ± 0.45 mo) were raised under two systems: 32 heifers (4 groups; 8 animals/pasture) raised on pasture (PAST), and 31 heifers (3 pens of 8 and 1 pen of 7) raised in a beddedpack barn (CONF) for 5 months. CONF was fed a high-forage diet with corn and grass silage, while PAST was supplemented with a ground corn and corn gluten mix (0.5% BW/d). Diets were targeted for an average daily gain (ADG) of 0.91 kg/d. Body weight (BW), condition score (BCS), hip height (HH), wither height (WH), hip width (HW), body length (BL), and heart girth (HG) were taken at the beginning and end of the grazing season. Backfat and rump fat ultrasounds were done to assess subcutaneous fat depth at the end of the season. Statistical analysis was performed based on a completely randomized design using PROC MIXED in SAS. BW, ADG and body measures were similar between the treatments (P=0.22). However, backfat was greater in CONF vs PAST (7.83 vs 6.97 mm, P=0.025, respectively), indicating different types of gain. Rump fat was similar in CONF vs PAST (10.7 vs 9.8 mm, P=0.23, respectively). Initial BCS diverged between CONF and PAST (3.21 vs 3.31, P=0.035), however final BCS was similar (3.43, P=0.90). Overall, PAST heifers performed similar to CONF heifers, but with less backfat accumulation. This may reduce the risk of metabolic disorders associated with high body fat content when animals begin lactation.