Effects of group housing and incremental hay supplementation in calf starters at different ages on growth performance, behavior, and health

Abstract

The present study examined the effects of age at group housing and age at incremental hay supplementation in calf starters from 7.5 to 15% (dry matter, DM) and their interaction on growth performance, behavior, health of dairy calves, and development of heifers through first breeding. A total of 64 calves (n = 16 calves/treatment, 8 male and 8 female) were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement, with age at group housing (early = d 28 ± 2, EG vs. late = d 70 ± 2, LG; 4 calves per group) and age at incremental hay supplementation of calf starters from 7.5 to 15% of DM (early = d 42 ± 2 d, EH vs. late = d 77 ± 2, LH) as the main factors. All calves (female and male) were weaned at 63 days of age and observed until 90 days of age. Heifer calves were managed uniformly from 90 days of age until first calving to evaluate the long-term effects of treatment. No interactions were observed between age at group housing and age at incremental hay to calves on starter feed intake, performance, calf health and behavior, and heifer development through first breeding, which was contrary to our hypothesis. The age at which incremental hay supplementation was administered had no effect on starter feed intake, growth performance, or heifer development until first calving. When EG calves were compared with LG calves, nutrient intake (starter, total dry matter, metabolizable energy, neutral detergent fiber, starch, and crude protein), average daily gain, and final body weight increased. In addition, frequency of standing decreased and time and frequency of eating increased in EG calves compared to LG calves. Overall, early group housing leads to improved growth performance in dairy calves with no negative effects on calf health compared to late group housing.

Figure 1

Overview of the animal experiment. A total of 64 calves (n = 16 calves/treatment, 8 male and 8 female) were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement with age at group housing (early = d 28 ± 2, EG vs. late = d 70 ± 2, LG) and age at incremental hay supplementation in calf starters from 7.5 to 15% of DM (early = d 42 ± 2 d, EH vs. late = d 77 ± 2, LH) as main factors (marked with different colors). Treatments included late group housing-late hay increment (LG-LH), late group housing-early hay increment (LG-EH), early group housing-late hay increment (EG-LH), and early group housing-early hay increment (EG-EH). Calves received 4 L/d from day 4 to 9, 6 L/d from day 10 to 20, 8 L/d from day 21 to 49, 6 L/d from day 50 to 55, and 4 L/d from day 56 to 59. Weaning was initiated by limiting milk intake to morning feedings (2 L) from day 60 to 62 of life. Calves were fully weaned at 63 days of age. All calves (female and male) were observed until they were 90 days of age, and heifers were observed until the first calving. Figure created using a web-based program BioRender (https://app.biorender.com).

Figure 2

Starter feed intake of calves (n = 16 calves/treatment, 8 male and 8 female) with one of the following treatments: Late grouping-late hay increment (LG-LH; black filled square), late grouping-early hay increment (LG-EH; black filled diamond), early grouping-late hay increment (EG-LH; red filled triangle), and early grouping-early hay increment (EG-EH; red filled circle) during the total period of study (from 1 to 13 wk of age). Data are presented as means ± SEM. Asterisk indicate a significant difference (*P < 0.05) between groups at a given time point.

Figure 3

Total dry matter intake of calves (n = 16 calves/treatment, 8 male and 8 female) with one of the following treatments: Late grouping-late hay increment (LG-LH; black filled square), late grouping-early hay increment (LG-EH; black filled diamond), early grouping-late hay increment (EG-LH; red filled triangle), and early grouping-early hay increment (EG-EH; red filled circle) during the total period of study (from 1 to 13 wk of age). Data are presented as means ± SEM. Asterisk indicate a significant difference (*P < 0.05) between groups at a given time point.

Figure 4

Body weight of calves (n = 16 calves/treatment, 8 male and 8 female) with one of the following treatments: Late grouping-late incremental hay (LG-LH; black filled square), late grouping-early incremental hay (LG-EH; black filled diamond), early grouping-late incremental hay (EG-LH; red filled triangle), and early grouping-early incremental hay (EG-EH; red filled circle) during the total period of study (from 1 to 13 wk of age). Data are presented as means ± SEM.