Straight-run vs. sex separate rearing for 2 broiler genetic lines Part 1: Live production parameters, carcass yield, and feeding behavior

Abstract

The objective of this experiment was to evaluate the effects of raising broilers under sex separate and straight-run conditions for 2 broiler strains. Day-old Ross 308 and Ross 708 chicks (n = 1,344) were separated by sex and placed in 48 pens according to the rearing type: sex separate (28 males or 28 females) or straight-run (14 males + 14 females). There were 3 dietary phases: starter (zero to 17 d), grower (17 to 32 d), and finisher (32 to 48 d). Birds' individual BW and feed intakes were measured at 12, 17, 25, 32, 42, and 48 d to evaluate performance. At 33, 43, and 49 d, 4 birds per pen were sampled for carcass yield evaluation. Additionally, from 06:00 to 06:30, 13:00 to 13:30, and 22:00 to 22:30, video records were taken to assess behavior at 45 days. Data were analyzed as CRD with a 2 × 3 factorial arrangement of treatments over time. Throughout the experiment Ross 308 were heavier than the 708, and after 17 d, male pens had the heavier birds, followed by straight-run and then females. Straight-run pens had higher BW CV in comparison with sex separate pens. Sex separate male BW was negatively impacted from 17 to 32 days. On the other hand, females raised sex separate were heavier than females raised straight-run with lower CV from 25 to 41 days. Post 25 d, FCR was the lowest in male pens whereas feed intake was the highest for these pens after 17 days. Overall, males had total carcass cut-up weights higher than straight-run and females at the 3 processing times. The Ross 708 had higher white meat yields, whereas 308 had higher yields for dark meat. Feeding behavior results were not consistent over time. However, from 13:00 to 13:30, birds in female pens spent more time eating, followed by straight-run and then males. In conclusion, raising females in a straightrun system negatively impacted performance and CV, whereas males benefited from straight-run rearing, with the differences being possibly related to feeder space competition.

Performance, Growth Curves and Carcass Yield of Four Strains of Broiler Chicken

“…There was a significant interaction (p<.005) among the factors for the variables WG and FI, in which the French, Hubbard and Cobb showed greater homogeneity between males and females, differently from Ross in which the males presented greater weight gain in the first week when compared to the females. Similar result to Da Costa et al (2017) was found when evaluating the performance of the Ross strain in mixed or single sex, the males had higher WG than females. The results observed in the WG are justified by the increase in the FI of the birds, i.e., birds with higher FI showed higher WG, justifying the absence of significant results (p>.005) for the FC variable.…”

Multiple Amino Acid Supplementations to Low-Protein Diets: Effect on Performance, Carcass Yield, Meat Quality and Nitrogen Excretion of Finishing Broilers under Hot Climate Conditions

“…Wide variations in amino acid digestibility have been reported in animal source proteins, particularly in terms of batch-to-batch differences [ 34 ]. The differences in responses to Arg or Val addition may be due to the difference in dietary protein sources, inclusion levels and amino acid requirements for broiler males and females [ 35 , 36 , 37 , 38 ]. It has been suggested that the protein and/or amino acid levels of the diets, strain, and the age of the birds may affect the response to the level of amino acid addition [ 7 , 39 ].…”

Análise Econômica Da Produção Avícola De Corte Por Gênero Em Diferentes Estruturas De Governança

“…Por meio das médias apresentadas na Figura 1, verifica-se que o fator de produção obtido em aviários em que foram alojados somente machos (FP = 323,93) foi 18% superior ao apresentado em instalações exclusivas de fêmeas (FP = 274,61) e 6,7% maior que em galpões com aves não sexadas (FP = 303,71). Gottardi et al (2019), Api et al (2017), Da Costa et al (2017 e Martins et al (2012), em avaliações de produtividade associadas à separação das aves de acordo com seus gêneros, também constataram que lotes exclusivos de machos apresentaram melhores indicadores zootécnicos que lotes de aves não sexadas (mistas) e lotes de fêmeas.…”

“…Estudos sobre desempenho produtivo de frangos de corte, de acordo com a linhagem e o gênero, indicam que os resultados zootécnicos da criação exclusiva de machos são melhores que os obtidos em galpões de aves não sexadas e de fêmeas (GOTTARDI et al, 2019;API et al, 2017e MARTINS et al, 2012. Além destas constatações, Da Costa et al (2017) ainda observaram que a produção mista (sem separação das aves de acordo com o sexo) favoreceu machos e prejudicou fêmeas em comparação com criações exclusivas para cada um desses gêneros.…”