Poultry

Three experiments were conducted to evaluate methodologies and determine the digestibility of calcium (Ca) in ingredients of animal origin, using a completely randomized design. In the first experiment, the direct, regression, and substitution methods were compared to determine the true digestibility of calcium in fishmeal (FM). The true ileal digestibility coefficients (TIDCs) obtained were 0.7558 (substitution), 0.6856 (direct), and 0.6130 (regression). Compared with the regression method, the substitution method resulted in greater digestibility. In the second experiment, the TIDCs of three meat and bone meals (MBM) were evaluated by the direct method. The observed values were 0.6212 (MBM1), 0.5393 (MBM2), and 0.8181 (MBM3). The MBM3 resulted in greater digestibility, while there was no significant difference between MBM1 and MBM2. In the third experiment, the TIDC values of the calcium in three poultry byproduct meal (PBM) samples were determined by the direct method, with coefficients of 0.9440 (PBM1), 0.8673 (PBM2), and 0.9127 (PBM3). No significant differences were observed between the evaluated PBM. The substitution and direct methods were effective for FM. The TIDCs of the MBMs ranged from 0.5393 to 0.8181, whereas those of the offal meals ranged from 0.8673 to 0.9440, indicating the importance of considering the differences in calcium digestibility among the ingredients. The direct method is the most efficient and recommended method for estimating true Ca digestibility because of its simplicity and reduced need for analysis and animals. Individually evaluating each source of Ca in broiler feed formulations is essential because of the wide variation in digestibility between them.

In bird eggs, the theoretical expectation of a primary sex ratio (at conception) of 50:50 males/females often fails to materialize. Using PCR technology for sex verification in this pilot study, we evaluated the primary sex ratio of 128 fertilized domestic goose eggs (Anser anser) early in the laying season. Over 24 consecutive days of egg collection, 37% more males were found (58% males vs. 42% females). This male-biased trend gradually declined over the period, but an excess of males was still observed. Among the factors for predicting the male sex ratio bias in a particular goose was the egg weight, i.e., heavier eggs tended towards a male phenotype. The embryo sex of the first egg laid and the egg weight change dynamics over the laying period were also noted. The correlation between actual and predicted data was calculated, taking into account three parameters, and found to be 0.724. To explain the effect of an implicit random/non-random process more adequately, we introduced the concept of biased randomness. As well as being of academic interest, research on sex ratio bias is crucial for goose breeding/reproduction programs and important as a step towards understanding the physiological mechanisms that underly sex ratio bias in these animals.

The present study provides a socio-economic characterization of an endangered turkey population in Europe for the first time, using the example of a southern Spanish population. To this end, 10 Andalusian turkey breeders were subjected to a 102-item survey, which included the following sections: personal and educational profile, the role of women in breeding, availability and conditions of facilities, welfare conditions, other equipment, maintenance and hygiene, farm access, feeding management, reproductive and replacement management, mortality, market value, and motivations for breeding. The results exhibited a wide variety in the breeder and rearing system attributes. However, the respondents agreed that rearing local breeds was a non-professionalized hobby. Farmers have generally old facilities and makeshift equipment for breeding the animals, which show strong ancestral instincts and a low requirement for breeding. The main purpose of their rearing is for self-consumption; however, there is an established sale demand for meat associated with Christmas. Breeders show a strong emotional motivation for the preservation of this ancestral population, which shares the rearing system with other endangered breeds. Three different profiles of breeders, traditional, neo-rural, and new-peasant, are responsible for maintaining the population selflessly and without administrative support.