ABSTRACT
OBJECTIVE: The main goal of our current study was to improve the growth curve of meat animals by decreasing the birth weight while achieving a finishing weight that is the same as that before selection but at younger age. METHODS: Random regression model was developed to derive various selection indices to achieve desired gains in body weight at target time points throughout the fattening process. We considered absolute and proportional gains at specific ages (in weeks) and for various stages (i.e., early, middle, late) during the fattening process. RESULTS: The point gain index was particularly easy to use because breeders can assign a specific age (in weeks) as a time point and model either the actual weight gain desired or a scaled percentage gain in body weight. CONCLUSION: The point gain index we developed can achieve the desired weight gain at any given postnatal week of the growing process and is an easy-to-use and practical option for improving the growth curve.
ABSTRACT
The breeding season was investigated in 174 female cats that were acclimated under a natural photoperiod, and determined the interval between birth and initial estrus (puberty) was determined in 125 cats. Although the breeding season differed noticeably among individual animals, the mean was 180.4 +/- 3.0 (SE) days between the end of January and the end of July. The interval between birth and first estrus ranged from 181 to 560 days, with a mean of 345.0 +/- 0.9 days. With respect to month of birth, the mean interval was 343.0 +/- 9.5 days in cats born between March and June. Among cats that were born between July and October, the mean intervals were 242.0 +/- 6.3 days in cats that exhibited estrus the year after birth and 519.2 +/- 5.8 days in those that exhibited estrus 2 years after birth.
