| Summary: | The effects of in ovo injected vitamin D3 source on eggshell temperature (ET) and performance of broilers through 14 D of age (doa) were investigated. Eggs from a 35-wk-old commercial Ross 708 broiler breeder flock were set in a single-stage incubator with 4 treatments representing each of 12 incubator tray levels (blocks). At 432 h of incubation (hoi), noninjected and diluent-injected (50 μL) groups were control treatment groups. Vitamin treatments in the commercial diluent were as follows: 2.4 μg of vitamin D3 (D3) or 25-hydroxylcholecalciferol (25OHD3). After injection, ET readings were recorded (435, 441, 453, 459, and 465 hoi) by infrared thermometry. Hatchability, hatchling BW, and percentage of male and female hatchlings were determined at 502 hoi. Equal numbers of male and female chicks were placed in each pen and grown out for 14 doa. On a per-pen basis, BW was recorded after hatching at day 7 and 14 doa, and BW gain, average daily BW gain, feed intake (FI), and feed conversion ratio (FCR) were calculated between 0 to 14 doa. The ET of eggs significantly fluctuated during the postinjection time period; however, the type of vitamin D3 source injected did not affect ET. Nevertheless, the injection of 25OHD3 resulted in a lower late embryo mortality than the diluent and D3 injection treatments. In addition, birds that received 25OHD3 had a lower FI and FCR than birds in all other treatments. In conclusion, the in ovo injection of 25OHD3 has the potential to improve early posthatch broiler performance without affecting ET.
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