Angelina Bossi Fraga

Análise de fatores genéticos e ambientais que afetam a infestação de fêmeas bovinas da raça Caracu por carrapatos (Boophilus microplus)

The objective of this study was to evaluate environmental aspects that affect the infestation of the Caracu cattle breed by the cattle tick Boophilus microplus (Canestrini, 1887) and to estimate genetic parameters for the level of this infestation. Countings of the parasite were done on female cattle from two herds, during all four seasons of the year, in two consecutive years (from September 1998 through July 2000). The number of ticks (NC) on one side of the animal was counted, and the infestations were also evaluated by scores (EC), according to the estimated number of parasites on the animal. Each animal had from one to eight observations. A total of 4,079 and 3,994 observations were obtained for NC and EC, respectively. The data were analyzed by the least squares method with a model that included the effects of herd (H), color of the animal (C), H x C, animal within H x C as error a, year, season, thickness of the hair, and age of animal as a covariable (linear and quadratic effects). The variance and covariance components were estimated by the restricted maximum likelihood derivative free method, using a model that included the effects of contemporary group (herd - year - season), hair thickness and age of the animal as a covariable (linear and quadratic effects), and the random additive direct and permanent environmental effects. Before the analyses, NC was transformed to log10 (n + 1) and EC was transformed to (x + 0.5) 1/2, where n is the number of ticks counted on the animal and x is the score for EC (0 to 4). The incidence of ticks was higher during the summer, and the ticker the hair the higher the infestation. The heritability and repeatability estimates were equal to 0.22 and 0.29, and 0.15 and 0.21 for NC and EC, respectively, and the genetic correlation between NC and EC was 1.00. The results indicate that there is enough additive genetic variation on tick numbers to support a selection program to increase resistance.

Desempenho e composição da carcaça de cordeiros deslanados terminados em confinamento com diferentes dietas

This study was performed with the objective of assessing the effects of feed and genotype on the quantitative characteristics of carcasses of lambs finished in a feedlot and estimate gross margins. Eighteen lambs of each genotype were used: Morada Nova, Santa Ines and cross-breed Dorper × Santa Ines. Feeds with low and high energetic levels consisted of 2.5 Mcal ME/kg DM and 2.94 Mcal ME/kg DM, respectively. A randomized complete design was used, with a 3 × 2 factorial scheme. The diets influenced daily weight gain, empty body weight, body score, feed efficiency and feedlot days, whilst the genotype promoted differences in all the variables studied. The caloric density of the diets influenced the biological hot and cold carcass yields, and the latter two were influenced by genotype. The more energetic diet (2.94 Mcal EM/kgDM) resulted in higher absolute weights of neck, shoulder, rib, loin and leg, but, in relative values, lambs fed with different energetic levels did not differ for these characteristics, regardless of the energetic level of the diet. The percentage yield of the cuts was influenced by the genotypes, except for the neck. The weights of all the cuts were influenced by genotypes. The treatment with the highest energy level resulted in the largest gross margin.

Desempenho de cordeiros cruzados em Alagoas, Brasil

Resumen pt: O objetivo deste trabalho foi avaliar cordeiros provenientes de cruzamentos e estimar alguns efeitos de ambiente que afetam o desempenho desses animais e...

Effect of diet and genotype on carcass characteristics of feedlot hair sheep

Avaliaram-se as caracteristicas qualitativas da carcaca de cordeiros deslanados em confinamento submetidos a dietas com dois niveis de energia. Foram utilizados 18 cordeiros de cada genotipo: Morada Nova, Santa Ines e mesticos Dorper x Santa Ines. As racoes de menor e maior nivel energetico foram constituidas de 2,5 e 2,94 Mcal EM/kg MS, respectivamente. Foram avaliados a conformacao e acabamento da carcaca, alem da composicao tecidual da perna. O escore para conformacao foi significativamente maior nos animais mantidos com a dieta de maior nivel de energia e nos mesticos Dorper x Santa Ines. Animais dos grupos Santa Ines e Dorper x Santa Ines apresentaram escore para cor da carne proximo a classe de vermelho, enquanto no genotipo Morada Nova foi proximo ao vermelho levemente escuro. A relacao musculo:osso dos mesticos Dorper x Santa Ines e dos Morada Nova foi superior a observada no grupo Santa Ines. A relacao musculo:gordura foi maior nos animais mantidos com a dieta de menor concentracao energetica. A area de olho-de-lombo dos mesticos Dorper x Santa Ines foi semelhante a do grupo Morada Nova e superior a do grupo Santa Ines. O indice de compacidade da carcaca, a espessura de gordura subcutânea e a espessura de gordura de cobertura sobre a superficie da 12a costela foram maiores nos animais submetidos a dieta de maior nivel energetico. A gordura da perna foi o unico tecido influenciado pela densidade calorica das dietas, enquanto o tecido osseo sofreu influencia dos genotipos, uma vez que a raca Santa Ines apresentou o maior percentual desse tecido. O genotipo e o nivel de energia da dieta influenciam a conformacao de carcaca. Dietas com maior densidade energetica melhoram o indice de compacidade da carcaca e espessura de gordura subcutânea.

Caracterização Morfométrica de Ovinos Deslanados Cabugi e Morada Nova

Foram avaliadas caracteristicas morfometricas e indices zootecnicos em 71 ovinos deslanados dos grupos locais Cabugi e Morada Nova nos municipios de Major Izidoro, Mata Grande e Piranhas, localizados na regiao semi-arida do Estado de Alagoas, no periodo de agosto de 2006 a janeiro de 2007. As caracteristicas estudadas foram peso, comprimento do animal, altura do posterior, altura do anterior, perimetro toracico, perimetro escrotal, comprimento da cabeca, largura da cabeca, indice corporal, indice corporal relativo, indice de relacao cernelha:garupa e indice de relacao perimetro toracico-cernelha. Foram obtidas estatiticas descritivas das caracteristicas morfometricas e dos indices zootecnicos de acordo com a estimativa de idade, sexo e grupos geneticos em estudo. Os animais Cabugi foram classificados como indice corporal medio e pernas curtas. Os ovinos Morada Nova apresentaram indice corporal curto.

Genetic analysis of the infestation of females of the Caracu cattle breed by Horn Fly (Haematobia irritans irritans) (L.) (Diptera, Muscidae)

The objective of this study was to evaluate environmental factors that affect infestation of Caracu cattle breed by horn fly (Haematobia irritans) and to estimate genetic parameters for level of infestation. Infestation was evaluated on females from two herds in two consecutive years. Total number of flies on animals (FC) was counted, an infestation score (FS: 1 to 5) was recorded according to the estimated number of flies on animals, and number of parasites in photographs (FF) taken when the animals were evaluated was also counted. On each animal from one to eight observations were taken. A total of 3,836, 2,751 and 3,754 records from 718 animals were obtained for FC, FF and FS, respectively. The incidence of flies was lower during winter and higher during summer, and the thicker the hair coat of the animal the greater the infestation. Heritabilities and repeatabilities were equal to 0.10 and 0.10, 0.08 and 0.12, and 0.06 and 0.08, for FC, FF and FS, respectively. Findings indicate that selection for FC will result in low genetic progress and that animals should be evaluated more than once for selection purposes.

Desempenho de Bezerros Nelore e Cruzados no Estado de Alagoas

Este trabalho foi realizado com o objetivo de avaliar o desempenho de bezerros Nelore e cruzados e estudar efeitos fenotipicos que afetam o desempenho desses animais no Estado de Alagoas. As caracteristicas estudadas foram peso ao nascer (PN), peso aos 210 dias de idade (P210) e ganho de peso do nascimento ao desmame (GD). Foram incluidos no modelo matematico os efeitos fi xos de fazenda, genotipo (Nelore, ½Blonde d’Aquitaine + ½Nelore, ½Red Angus + ½Nelore e ½Senepol + ¼Red Angus + ¼Nelore) e grupo contemporâneo (sexo, mes e ano de nascimento). O efeito de grupo contemporâneo nao foi signi fi cativo (P>0,05) para PN, mas foi signi fi cativo (P<0,05) para P210 e GD. Os efeitos de genotipos e fazenda foram signi fi cativos (P<0,01) para todas as caracteristicas em estudo. Os bezerros cruzados ½Senepol + ¼Red Angus + ¼Nelore foram superiores para PN e, juntamente com ½Red Angus + ½ Nelore, foram superiores para P210 e GD. Animais puros Nelore apresentaram as menores medias para P210 e GD, comparado aos demais grupos geneticos.

Body morphometric measurements in Murrah crossbred buffaloes (Bubalus bubalis)

ABSTRACT The morphometry study contributes to the comprehension of the animal conformation. The objective of this research was to study the morphometric measurements of crossbred female Murrah buffaloes, aiming to give subsidies to the study of the relations between their body structures and productive or reproductive performances. The morphometric body measurements studied were: the breast width (BW), thigh width (THW), hip width (HW), rump width (RW), rump length (RL), animal depth (AD), body length (BL), front height (FH), hind height (HH), shoulder width (SW), thorax width (TW), loin width (LW), distance from the head to the ischium (DHI) and thoracic perimeter (TP). Descriptive and Pearson correlation analysis were performed. The average values were 43.72 (BW), 51.42 (TW), 39.99 (HIW), 25.38 (RW), 39.78 (RL), 71.72 (AD), 143.07 (BL), 130.05 (FH), 130.80 (HH), 33.00 (SW), 35.25 (CHW), 3.79 (LW), 180.15 (LHI) and 201.30 (TP). The highest correlations were 0.74 for the SW/CHW, 0.69 for the HIW/TW, 0.68 for the TP/RH, 0.66 for the CW/HIW, 0.65 for the HW/RH and 0.64 for the TW/CW. These correlation coefficients between the body morphometric measurements themselves can be used in the selections programmes.

Agregação de Valor em Carcaça de Cordeiros Deslanados por Meio de Cortes Especiais

Objetivou-se avaliar as porcentagens dos cortes em relacao ao peso de carcaca fria, estimar as correlacoes e o valor agregado entre os diferentes cortes. Foram utilizados 44 cordeiros deslanados e as variaveis em estudo foram: peso da carcaca quente, peso da carcaca fria, rendimento da carcaca quente, rendimento carcaca fria e os cortes comerciais: pescoco, paleta, perna, file, contra-file, picanha e carre. O peso medio ao abate foi 28,26 kg. As correlacoes entre a perna e os cortes, carre e picanha, foram respectivamente, 0,99 e 0,98. Foi observado aumento linear entre o peso de carcaca fria e os cortes especiais estudados. O fracionamento da carcaca em cortes especiais proporcionou elevacao, em ate 201,98%, no valor da comercializacao da carne de cordeiro. Quanto maior o peso da perna, maiores os pesos dos cortes carre e picanha.