USE OF HEAT LAMPS IN FARROWING PENS

The correlation coefficients between the various successive weight periods were obtained from data on the 3/4 Duroc x 1/4 English Large Black Landrace line of pigs of the University of Puerto Rico's Agricultural Experiment Station, Mayagüez Campus. These periods were at birth, at 21 days, at weaning time, and at 154 days of age. The data of 41 boars, 86 barrows, and 138 gilts covering the period from the fall of 1961 to the fall of 1965 were included. All the correlation coefficients found were positive and significant, with the exception of birth to weaning, and to 154 days, and 21 days to 154 days of age in the boars. Those between the weaning weight and at 154 days of age were on the order of over +0.60 for all sexes. This fact was further confirmed by the logistic equation used with the same data and included here. Even though the boars were heavier than the barrows in all the weight periods, and these, in order, to the gilts, only at birth and at 154 days of age, there was a significant difference in favor of boars and barrows as compared with gilts.

OPTIMUM WEIGHT TO WHICH PIGS SHOULD BE CARRIED FOR MAXIMUM PROFIT

An experiment was carried out using 80 pigs of the 3/4 Duroc x 1/4 English Large Black Landrace line to study the influence of slaughter weight on the carcass quality and the feed efficiency. These pigs were randomly assigned to one of four lots, from each one of which pigs were slaughtered when they reached 125, 150, 175, and 200 pounds of live weight respectively. As slaughter weight increased the percentage of the four primal cuts on a chilled-carcass basis, the percentage of ham and picnic on a chilled-carcass basis, and the feed efficiency decreased significantly, while the amount of fat in carcasses increased significantly.

Seventeen litters of pigs were divided into three groups and each group was weaned at a different age. Weaning ages were 21, 42, and 56 days. The pigs weaned at 21 days were started on a ration suited for small pigs; it consisted of about 20-percent crude protein 1 week before the weaning date. All the others were started on the same ration at 21 days. The feed consumption of each group was recorded. All of the pigs were weighed at 21, 42, and 56 days. The evaluation of each weaning method was based on these two characteristics. The results obtained indicated that there was a highly significant difference in favor of the pigs weaned at the customary 56-day age. They consumed less concentrate feed and weighed more at weaning time, favored, no doubt, by the additional milk obtained from theh dams. If weaning is to occur at all before 56 days, it apparently should occur at 21, rather than at 42 days. Since differences are not significant between these two groups, weaning at 21 days will save some time and extra labor.