Seasonal effect on growth of dairy calves in the southeastern United States.
Research output: Chapters, Conference Papers, Creative and Literary Works › RGC 32 - Refereed conference paper (with host publication) › peer-review
Author(s)
Related Research Unit(s)
Detail(s)
| Original language | English |
|---|---|
| Title of host publication | Abstracts of the 2024 American Dairy Science Association® Annual Meeting |
| Publisher | Elsevier Inc. |
| Publication status | Published - 2024 |
Publication series
| Name | Journal of Dairy Science |
|---|---|
| Number | Supplement 1 |
| Volume | 107 |
| ISSN (electronic) | 1525-3198 |
Conference
| Title | 2024 American Dairy Science Association® Annual Meeting |
|---|---|
| Location | Palm Beach County Convention Center |
| Place | United States |
| City | West Palm Beach |
| Period | 16 - 19 June 2024 |
Link(s)
| Permanent Link | https://scholars.cityu.edu.hk/en/publications/publication(c0b92e6e-0837-4e77-b269-ae45385859b4).html |
|---|
Abstract
Our aim was to evaluate seasonal effects on growth of dairy calves in Georgia. Holstein calves (n = 48/season) from UGA research dairy located in Tifton, Georgia, were enrolled at birth during summer (June to August, BW = 40 ± 4 kg) and winter (November to January, BW = 42 ± 4 kg). Similar general management and feeding practices were
applied to calves in both seasons. Calves were housed in individual polyethylene hutches with sand as bedding material. Starting at 2 d of age (DOA), calves were fed a 26:17 milk replacer (MR) and calf starter
(CS) was offered ad libitum. Weaning started at 43 DOA by reducing MR by 50% until 49 DOA when MR feeding ceased. Calves remained enrolled until 63 DOA. Calf starter intake was recorded daily. Ambient temperature (AT) and relative humidity (RH) were recorded hourly. Rectal temperature and respiration rate were assessed 3× per week, and BW was measured weekly. The mixed procedure of SAS was used to analyze repeated measures data. Season, time, and their interactions were included as the fixed effect. The coefficient of variation (CV) of
hourly AT within a day was calculated as a proxy of within-day AT variation. The CV of daily average AT within week was used as the proxy of day-to-day AT variation. The correlation analysis between ADG and environmental parameters was performed using GLM procedure. Summer months had greater AT (27 vs. 13°C) but similar RH (83% vs. 81%) compared with winter, respectively. Calves in summer had greater (P < 0.01) rectal temperature and respiration rate than winter calves. Seasons had no effect on CS intake before weaning, but summer calves had greater CS intake at 9 wk of age than winter calves (season × time: P < 0.01). No seasonal effect was observed for BW, but summer calves had greater ADG at wk 3, 5, and 9 of age (season × time: P < 0.01). Among environmental parameters, preweaning ADG is negatively correlated with within day AT variation during winter (P < 0.01, r2
= 0.11) and negatively correlated with day-to-day AT variation during summer (P < 0.01, r2 = 0.06). In conclusion, in Georgia, the within-day and day-to-day AT variations significantly affect preweaning calf growth.
applied to calves in both seasons. Calves were housed in individual polyethylene hutches with sand as bedding material. Starting at 2 d of age (DOA), calves were fed a 26:17 milk replacer (MR) and calf starter
(CS) was offered ad libitum. Weaning started at 43 DOA by reducing MR by 50% until 49 DOA when MR feeding ceased. Calves remained enrolled until 63 DOA. Calf starter intake was recorded daily. Ambient temperature (AT) and relative humidity (RH) were recorded hourly. Rectal temperature and respiration rate were assessed 3× per week, and BW was measured weekly. The mixed procedure of SAS was used to analyze repeated measures data. Season, time, and their interactions were included as the fixed effect. The coefficient of variation (CV) of
hourly AT within a day was calculated as a proxy of within-day AT variation. The CV of daily average AT within week was used as the proxy of day-to-day AT variation. The correlation analysis between ADG and environmental parameters was performed using GLM procedure. Summer months had greater AT (27 vs. 13°C) but similar RH (83% vs. 81%) compared with winter, respectively. Calves in summer had greater (P < 0.01) rectal temperature and respiration rate than winter calves. Seasons had no effect on CS intake before weaning, but summer calves had greater CS intake at 9 wk of age than winter calves (season × time: P < 0.01). No seasonal effect was observed for BW, but summer calves had greater ADG at wk 3, 5, and 9 of age (season × time: P < 0.01). Among environmental parameters, preweaning ADG is negatively correlated with within day AT variation during winter (P < 0.01, r2
= 0.11) and negatively correlated with day-to-day AT variation during summer (P < 0.01, r2 = 0.06). In conclusion, in Georgia, the within-day and day-to-day AT variations significantly affect preweaning calf growth.
Research Area(s)
- season, temperature variation, calf
Citation Format(s)
Seasonal effect on growth of dairy calves in the southeastern United States. / Roper, A. M.; Orellana Rivas, R. M.; Marins, T. N. et al.
Abstracts of the 2024 American Dairy Science Association® Annual Meeting. Elsevier Inc., 2024. (Journal of Dairy Science; Vol. 107, No. Supplement 1).
Abstracts of the 2024 American Dairy Science Association® Annual Meeting. Elsevier Inc., 2024. (Journal of Dairy Science; Vol. 107, No. Supplement 1).
Research output: Chapters, Conference Papers, Creative and Literary Works › RGC 32 - Refereed conference paper (with host publication) › peer-review
