Worsaae H, Schmidt M
Acta Vet Scand. 1980;21(4):640-57. doi: 10.1186/BF03546852.
Comparisons were made of Cortisol concentration and behavioural activity between piglets weaned at 3 weeks of age (early weaned piglets), and piglets weaned at 8 weeks of age (control piglets). Early weaned littermates were placed in cages with a floor area of either 0.20 m per piglet or 0.15 m per piglet. At 8 weeks of age, the piglets in the control litters were moved from the sow and early weaned piglets were moved from the cages. All litters were placed in pens, 1 pen for each litter. Radioimmunoassay was used for plasma Cortisol determination. Behavioural activity included determination of play, aggressive behaviour and non-nutritive oral activity. Statistical analysis for possible association between plasma Cortisol concentration and age, housing conditions, litter and sequence of capture of littermates for blood collection revealed a complex pattern. Generally, higher plasma Cortisol concentrations and more aggressive and non-nutritive oral activity, but less playing activity, were associated with early weaning. Plasma Cortisol concentration in individual piglets was positively correlated to both aggressive and non-nutritive oral behaviour, but was negatively correlated to playing behaviour. It is concluded that early weaning is a stressor.
对3周龄断奶仔猪（早期断奶仔猪）和8周龄断奶仔猪（对照仔猪）的皮质醇浓度和行为活动进行了比较。早期断奶的同窝仔猪被放置在每头仔猪占地面积为0.20平方米或0.15平方米的笼子里。在8周龄时，对照窝的仔猪从母猪身边转移，早期断奶仔猪从笼子里转移出来。所有窝仔猪都被安置在猪栏里，每窝一栏。采用放射免疫分析法测定血浆皮质醇。行为活动包括对玩耍、攻击行为和非营养性口腔活动的测定。对血浆皮质醇浓度与年龄、饲养条件、窝别以及采血时同窝仔猪的捕获顺序之间可能存在的关联进行的统计分析显示出一种复杂的模式。一般来说，较高的血浆皮质醇浓度、更多的攻击行为和非营养性口腔活动，但玩耍活动较少，与早期断奶有关。个体仔猪的血浆皮质醇浓度与攻击行为和非营养性口腔行为均呈正相关，但与玩耍行为呈负相关。得出的结论是，早期断奶是一种应激源。
