Length-growth patterns with the prediction and adjustment equation for length of pigs from birth to 70 days of age

The purpose of this experiment was to determine the length-growth patterns in pigs from birth to weaning, to determine if length can be predicted during this period, and to determine if an effective adjustment factor for length can be calculated. The lengths of each pig were measured from the poll of the head along the spinal column to the tail head. The weights and measurements were taken within 24 hours after birth and again at 1, 2, 3, 4, 5, 6, 7, 9, 17, and 24 weeks of age. The data were analyzed by the Statistical Analysis System using the model: Ŷ = Ym̳ + b₁ (Agep̳-Agem̳) + b₂ (Agep̳²-Agem̳²) + b₃ (Agep̳̳³-Agem̳³) where: Ŷ = predicted length Ym̳ = measured length used to predict or adjust other lengths b₁ = .303 b₂ = -.003 b₃ = .00003 Agep̳ = age in days of length to be predicted Agem̳ = age in days of measured length It was found that the length-growth curve from birth to weaning was linear, that length could be predicted during this time period and the lengths of pigs of different ages could be adjusted to a common age. The equation for predicting and/or adjusting length would probably be of little value to the commercial pork producer as a selection criterion because length is not significantly correlated with carcass yield, performance of the pig, et cetera. However, longer carcasses are associated with faster rates of gain and more desirable backfat. Therefore, the adjustment factor would be valuable to the researchers because they could adjust the length of the pigs to a common length to get the most accurate research data.