One hundred six female Holstein calves [body weight (BW) = 41.5 +/- 0.37 kg and 11.2 +/- 0.3 d old] were used to evaluate the effects of physical form of a starter on animal performance and starter intake. Calves were randomly allocated to 2 treatments consisting of either a multiparticle or a pelleted starter. Both starters had exactly the same ingredient and nutrient composition but differed in their physical form. Calves received 4 L/d of the same milk replacer at a 150 g/kg dilution rate in 2 offers of 2 L each until they consumed an average of 300 g/d of starter (as fed) for 2 consecutive days; then the dilution rate was decreased to 120 g/kg until the age of 49 d when milk replacer was limited to 1 daily dose of 2 L until 57 d of age. Calves were kept in individual hutches for at least 1 wk after weaning. Body weight was measured at the beginning of the study and at 49 and 64 d of age. The median perimeters for the multiparticle and pelleted starters were 0.61 +/- 0.016 and 2.71 +/- 0.082 cm, respectively. Overall starter consumption was greater in calves receiving the multiparticle starter (944.8 +/- 30.01 g/d) than in those receiving the pelleted starter (863.9 +/- 32.04 g/d). There were no differences in the total milk replacer intake between the 2 treatments. Calf BW when leaving the individual hutches at the end of the study was similar between both treatments. Consequently, feed conversion efficiency was greater in calves consuming the pelleted than the multiparticle starter up to 64 d of age, mainly due to the greater conversion efficiency obtained with the pelleted than with the multiparticle starter after the preweaning period. It is concluded that pelleted starters may result in lower dry feed consumption compared with multiparticle starters, but because final BW was similar in both treatments, feed efficiency of calves consuming pelleted starters may be greater than that of calves consuming multiparticle starters. Therefore, when feeding a starter with similar nutrient composition to the one used in this study, there seems to be an economic advantage associated with feeding the starter in a pelleted form compared with a multiparticle form.

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Two experiments were conducted to evaluate whether performance could be improved and incidence of respiratory problems decreased either by allocating 6 additional days of individual housing after weaning or by moving calves in groups before weaning at 2 different ages. The first experiment involved 320 female calves that received 2L of milk replacer (MR) twice daily until 49 d of age, and then 2L of MR once daily until weaning at 56 d of age. Half of the calves were allowed to remain individually housed for an additional 6d after weaning, and the other half were moved immediately after weaning to a different pen holding 8 calves. The second experiment involved 240 female calves that received 2L of MR twice daily until 49 d of age, and then 2L of MR once daily. Half of the calves were moved at 49 d of age to superhutches holding 8 calves with an elevated trough that was used to continue delivering MR; the other half remained individually housed until the age of 56d and were then moved to the superhutches, where they also continued to receive MR. Growth and incidence of respiratory problems were recorded in both experiments, and feed intake was recorded in experiment 2. Calves moved to groups immediately after weaning reached the target BW 6d earlier and experienced a lesser incidence of respiratory afflictions than those grouped 6d after weaning. From experiment 2, calves grouped at 49 d of age had a greater average daily gain and BW at 56 d of age as a result of a greater total solid feed consumption compared with those grouped at 56 d of age. Calves grouped at 56 d, however, had a greater average daily gain between 56 and 64 d of age (the week following grouping for the calves in the 56-d treatment) than those grouped at 49 d of age. Overall, the proportion of animals affected by a respiratory problem between 49 and 112 d of age did not differ between treatments. However, calves grouped at 49 d of age had a lower number of respiratory cases than those grouped at 56 d of age. It is concluded that moving calves from individual hutches to groups of calves in superhutches immediately after weaning is preferable to waiting an additional 6d. In addition, moving calves from individual hutches to groups of 8 in superhutches at 49 d of age and starting to reduce MR offering once grouped is preferable to starting to reduce MR while calves are individually housed.

A study consisting of 2 experiments was conducted with the aim of determining the effects of previous history of bovine respiratory disease (BRD) on animal performance and health status of transition calves housed in groups. In both experiments, calves were housed in individual hutches until weaning age at 58 d. Before weaning, BRD incidences were individually recorded on a daily basis. Following weaning, calves were moved into super hutches in groups of 8, based on their history of respiratory afflictions, and growth performance and BRD incidences were recorded for 57 d. In experiment 1, 144 female Holstein dairy calves (initial BW=72.6±1.2 kg; age=58.5±0.8 d) were distributed in 6 super hutches composed of 8 calves with no previous history of BRD (HHH), 6 super hutches composed of 6 calves without and 2 calves with a previous episode of BRD (HHR), and 6 super hutches housed 5 calves without a history of BRD and 3 calves with previous respiratory afflictions (HRR). In experiment 2, 144 Holstein female calves [58.0±0.9 d; 72.5±0.9 kg of body weight (BW)] were distributed in 2 treatments consisting of 9 super hutches housing integrally 8 calves with no previous BRD, and 9 super hutches housing integrally calves with a previous BRD case. The number of BRD cases after weaning progressively increased from HHH to HRR as the proportion of calves previously affected by BRD within super hutch increased, mainly due to the fact that both animals affected by BRD before weaning and those with no previous history of BRD had more relapses in HHR and HRR groups than in the HHH group. Odds of incurring BRD after grouping were 3.89 greater in calves that had a previous case of BRD than in those that did not. The average time elapsed between commingling the animals and the appearance of the first BRD case was shorter when calves that had at least one BRD episode prior to weaning were present in a group (10.8±3.3 d) than when the group was formed with calves that had never experienced BRD before weaning (22.5±3.3 d). Final BW (at 115 d of life) and average daily gain tended to decrease as the number of BRD cases incurred increased. In experiment 2, calves in the HHH group reached a greater BW at the end of the study than those in the RRR group and tended to have a greater average daily gain in the HHH group than in the RRR group. It is concluded that forming groups of animals with a previous BRD history should minimize the incidence of respiratory cases in those groups of calves formed by animals without a previous history of respiratory disease.

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