Floor eggs in goose breeders: patterns, genetic and environmental influences, and physiological indexes

A floor egg is an egg that is not laid in the nest, which is a prevalent issue in many fowl breeder farms, lowering egg collection efficiency, hatching performance, and economic benefits. Although the pattern and influencing factors of floor laying have been extensively reported in chickens and ducks, it is not clear in geese. Herein, the Yangzhou goose breeders were selected, and the time and location preferences, genetic and environmental influences, and physiological indexes in floor laying were investigated. The results revealed distinct time and location preferences existed. More floor eggs were laid from 2:00 to 5:00 and 8:00 to 12:00 am, with a concentration observed in the feed trough. Moreover, the proportion of floor eggs was higher at the early stage than at other stages of the laying cycle, and the fast-growing line laid more floor eggs than dual-purpose and high-yielding lines (P < 0.05). In addition to genetic factors, the effect of environmental influences on floor eggs was also surveyed. More floor eggs were observed in the family housing system than in large-group and small-population housing systems, and geese who reared in north-facing houses laid more floor eggs than in south-facing houses (P < 0.05). Physiological indexes were compared between floor-laying and nest-laying geese. Significantly decreased serum progesterone and prolactin levels were detected, alongside down-regulated gene expressions of progesterone receptor in ovaries, oxytocin receptor in both pituitary and ovaries, corticotropin-releasing hormone in ovaries, and dopamine receptor D2 in hypothalamus and ovaries in floor-laying geese compared to nest-laying geese (P < 0.05). In addition, a practical and inexpensive approach of adding a single decoy egg to the nest box effectively reduced the proportion of floor eggs (P < 0.05). Taken together, these data provide scientific information for patterns, genetic and environmental influences, and physiological indexes of floor eggs, thereby contributing to effective control of floor laying in goose breeders' production.