Stage of goose embryo development at oviposition depending on genotype, flock age, and period of laying

Effect of parent flock age on hatching, growth rate, and features of both sexes goose carcasses

The study aimed to assess the hatchability of goslings from parent flocks of geese in 4 laying seasons and to analyze the growth, carcass, and muscles characteristics. The hatching eggs from the White Kołuda geese from the 1st to 4th laying season were incubated by the waterfowl hatching technology. Hatchability rates were calculated. 40 goslings were selected from each group. The geese were reared and fattened for 16 wk, (sex ratio of 1:1). From the 1-day-old goslings and at the end of the fattening period, the pectoral muscles were sampled to evaluate the muscle fibers. The body weight of the geese and the growth rate were analyzed. Body measurements were taken on the day of slaughter (6 birds/each group). The dissection was performed and the tissue composition of the carcasses was analyzed, including the percentage of carcass elements. The results were analyzed in terms of the age of the parent flock and the sex of oat geese. Hatchability performance was similar in all groups. Lower body weight of geese from group I was demonstrated at 0, 1, 7, 10 to 12 wk compared to birds from older geese. The growth rate in this group was higher than in groups III (2nd wk) and IV (1st wk). From 4 wkof age, the males had a higher body weight. In 1-day-old male goslings, a higher diameter of muscle fibers was demonstrated than in females. The body measurements of ganders were significantly higher compared to females, except for the length of the jump. Males were characterized by a higher weight of carcass parts. However, the share of abdominal fat was higher in females. No significant differences were found in the remaining features. Geese from different ages’ parent flocks don't differ in the carcass features (the compensation phenomenon). The sex of the geese was influenced. It is reasonable to hatch goslings for fattening from parent flocks during 4 years of reproductive use.

Hissing of geese: caller identity encoded in a non-vocal acoustic signal

Non-vocal, or unvoiced, signals surprisingly have received very little attention until recently especially when compared to other acoustic signals. Some sounds made by terrestrial vertebrates are produced not only by the larynx but also by the syrinx. Furthermore, some birds are known to produce several types of non-syrinx sounds. Besides mechanical sounds produced by feathers, bills and/or wings, sounds can be also produced by constriction, anywhere along the pathway from the lungs to the lips or nostrils (in mammals), or to the bill (in birds), resulting in turbulent, aerodynamic sounds. These noises often emulate whispering, snorting or hissing. Even though hissing sounds have been studied in mammals and reptiles, only a few studies have analyzed hissing sounds in birds. Presently, only the hissing of small, nesting passerines as a defense against their respective predators have been studied. We studied hissing in domestic goose. This bird represents a ground nesting non-passerine bird which frequently produces hissing out of the nest in comparison to passerines producing hissing during nesting in holes e.g., parids. Compared to vocally produced alarm calls, almost nothing is known about how non-vocal hissing sounds potentially encode information about a caller's identity. Therefore, we aimed to test whether non-vocal air expirations can encode an individual's identity similar to those sounds generated by the syrinx or the larynx. We analyzed 217 hissing sounds from 22 individual geese. We calculated the Potential for Individual Coding (PIC) comparing the coefficient of variation both within and among individuals. In addition, we conducted a series of 15 a stepwise discriminant function analysis (DFA) models. All 16 acoustic variables showed a higher coefficient of variation among individuals. Twelve DFA models revealed 51.2-54.4% classification result (cross-validated output) and all 15 models showed 60.8-68.2% classification output based on conventional DFA in comparison to a 4.5% success rate when classification by chance. This indicates the stability of the DFA results even when using different combinations of variables. Our findings showed that an individual's identity could be encoded with respect to the energy distribution at the beginning of a signal and the lowest frequencies. Body weight did not influence an individual's sound expression. Recognition of hissing mates in dangerous situations could increase the probability of their surviving via a more efficient anti-predator response.