Characterization and valuing of hatchery waste from the broiler chicken productive chain.

Characterizing the waste generated from different agro-industrial segments enables the strategic management of residues, with the goal of maximizing recovery within the premises of a circular economy. This research aimed to determine the coefficient of waste generated in broiler chick hatcheries as well as to characterize the waste, taking into account the points of culling and the ages of the laying hens. Furthermore, the waste was used in composting with sheep manure (SM) at increasing inclusion rates (0:100, 10:90, 20:80, 30:70, 40:60, and 50:50). On average, 0.16 kg (DM) of hatchery waste is generated per kg of broiler chicks born. At the hatchery, at least 79% of the total disposal occurs at the hatcher stage. This value is impacted by chicken age (P < 0.05), with birds of a late laying age generating waste with higher contents of carbon (C), volatile solids (VS), ether extract (EE), and nitrogen (N). Culling during egg reception and the manual transfer process account for only 1.8% of the total waste generated on average and thus contribute little to the composition of the overall residues. However, the mechanical transfer process may represent up to 19.0% of the total waste generated by hens of an intermediate laying age. According to the average of all the composting stages, the maximum reduction in solids and C from the hatchery waste was reached when the waste accounted for 50% of the windrow composition. Such conditions resulted in organic fertilizer with the highest N content (2.8%), equivalent to 40.0% more than that in the treatment with no added hatchery waste. The compost resulting from 50% hatchery waste inclusion also had the highest humic acid to fulvic acid (HA:FA) ratio and the highest calcium content due to the higher proportion of eggshells. These findings lead to the recommendation for the inclusion of hatchery waste in composting with SM at a 50% rate by mass.

Population structure of Simmental beef cattle using pedigree analysis.

The purpose of this study was to estimate parameters related to the population structure and genetic diversity in the Simental breed based on the pedigree information of 77,553 animals. The individual coefficients of inbreeding and average relatedness, number of complete generations, coefficient of change of inbreeding, effective size, effective number of founders, number of ancestors and generation interval were calculated. Using the Simmental cattle information, the mean inbreeding and average relatedness coefficients were 1.49% and 0.99%, respectively. The effective number of founders and ancestors was 163 and 132, respectively, and the effective population size was 48.03. Despite the relatively small inbreeding coefficient, some of the estimated population parameters indicated the need to adopt measures to maintain the genetic variability of the population.

Multiple-trait random regression models for the estimation of genetic parameters for milk, fat, and protein yield in buffaloes.

In this study, genetic parameters for test-day milk, fat, and protein yield were estimated for the first lactation. The data analyzed consisted of 1,433 first lactations of Murrah buffaloes, daughters of 113 sires from 12 herds in the state of São Paulo, Brazil, with calvings from 1985 to 2007. Ten-month classes of lactation days were considered for the test-day yields. The (co)variance components for the 3 traits were estimated using the regression analyses by Bayesian inference applying an animal model by Gibbs sampling. The contemporary groups were defined as herd-year-month of the test day. In the model, the random effects were additive genetic, permanent environment, and residual. The fixed effects were contemporary group and number of milkings (1 or 2), the linear and quadratic effects of the covariable age of the buffalo at calving, as well as the mean lactation curve of the population, which was modeled by orthogonal Legendre polynomials of fourth order. The random effects for the traits studied were modeled by Legendre polynomials of third and fourth order for additive genetic and permanent environment, respectively, the residual variances were modeled considering 4 residual classes. The heritability estimates for the traits were moderate (from 0.21-0.38), with higher estimates in the intermediate lactation phase. The genetic correlation estimates within and among the traits varied from 0.05 to 0.99. The results indicate that the selection for any trait test day will result in an indirect genetic gain for milk, fat, and protein yield in all periods of the lactation curve. The accuracy associated with estimated breeding values obtained using multi-trait random regression was slightly higher (around 8%) compared with single-trait random regression. This difference may be because to the greater amount of information available per animal.

Effect of lactation length adjustment procedures on genetic parameter estimates for buffalo milk yield.

The objectives of this study were to estimate the genetic parameters for milk yield unadjusted and adjusted for days in milk and, subsequently, to assess the influence of adjusting for days in milk on sire rank. Complete lactations from 90 or 150 days of lactation to 270 or 350 days in milk were considered in these analyses. Milk yield was adjusted for days in milk by multiplicative correction factors, or by including lactation length as a covariable in the model. Milk yields adjusted by different procedures were considered as different traits. Heritability estimates varied from 0.17 to 0.28. Genetic correlation estimates between milk yields unadjusted and adjusted for days in milk were greater than 0.82. Adjusting for days in milk affected the parameter estimates. Multiplicative correction factors produced the highest heritability estimates. More reliable breeding value estimates can be expected by including short length lactation records in the analyses and adjusting the milk yields for days in milk, regardless of the method used for the adjustment. High selection intensity coupled to the inclusion of short length lactations and adjustment with multiplicative factors can change the sire rank..

Effect of lactation length adjustment procedures on genetic parameter estimates for buffalo milk yield

The objectives of this study were to estimate the genetic parameters for milk yield unadjusted and adjusted for days in milk and, subsequently, to assess the influence of adjusting for days in milk on sire rank. Complete lactations from 90 or 150 days of lactation to 270 or 350 days in milk were considered in these analyses. Milk yield was adjusted for days in milk by multiplicative correction factors, or by including lactation length as a covariable in the model. Milk yields adjusted by different procedures were considered as different traits. Heritability estimates varied from 0.17 to 0.28. Genetic correlation estimates between milk yields unadjusted and adjusted for days in milk were greater than 0.82. Adjusting for days in milk affected the parameter estimates. Multiplicative correction factors produced the highest heritability estimates. More reliable breeding value estimates can be expected by including short length lactation records in the analyses and adjusting the milk yields for days in milk, regardless of the method used for the adjustment. High selection intensity coupled to the inclusion of short length lactations and adjustment with multiplicative factors can change the sire rank..