Effects of Protein Level Sequence and Kind of Starter on Rate and Efficiency of Gain of Growing Swine, and on Carcass Characteristics

Ninety litters of pigs weaned at 5 weeks of age were used in an experiment conducted at four locations to determine the effects of protein level sequence and kind of starter (simplified vs. complex) on performance of pigs to 63 days, and particularly on rate and efficiency of gain subsequent to 63 days and on carcass characteristics. Protein level sequence prior to 63 days did not significantly affect 63-day weights or gain/feed. Pigs fed the complex starter consumed more feed and were significantly (P<.01) heavier at 63 days, but were no more efficient in conversion of feed to gain. There were significant differences between stations in feed intake/pig, 63-day weights and gain/feed. Within stations, pigs were significantly heavier at 63 days at three of four locations due to feeding the complex starter, but gain/feed was not improved. Protein level sequence did not significantly affect rate and efficiency of gain subsequent to 63 days, nor were there any significant effects on the measures of carcass leanness. Likewise, feeding the more complex starter during the period from 21 to 63 days with resultant heavier 63-day weights did not influence rate and efficiency of gain, or carcass characteristics. There were significant differences between stations in daily gains, gain/feed and carcass characteristics, but there were no significant station x treatment interactions for these response criteria. It appears that more severe nutritional restrictions than applied in this study, or in other studies cited, must be imposed during the early development of the young pig to cause significant effects on rate and efficiency of gain during the final growing period, and on carcass leanness.