Francisco Alberto de Moura Duarte

Is the American Zebu really Bos indicus

The American continent was colonized in the 16th century by Europeans who first introduced cattle of Bos taurus origin. Accounts register introduction of Bos indicus cattle into South America in the 19th and continuing through the 20th century, and most reported imports were males derived from the Indian subcontinent. In the present study we show, by using mitochondrial DNA (mtDNA) polymorphism, major participation of matrilineages of taurus origin in the American Zebu purebred origin, i.e., 79, 73 and 100% for the Nellore, Gyr and Brahman breeds, respectively. Moreover, we have created a restriction map identifying polymorphism among B. taurus and B. indicus mtDNA using three restriction enzymes. Results are discussed concerning American Zebu origins and potential use of this information for investigating the contribution of cytoplasmic genes in cattle production traits.

Responses of cattle to humans in open spaces: breed comparisons and approach-avoidance relationships.

Domestic cattle have paradoxical tendencies both to approach and to avoid humans. Approach (investigating a person lying on the ground) and avoidance (flight distance) were studied in 21 herds of 12Bos taurus, B. indicus, andB. taurus x B. indicus breeds located in a homogeneous, Brazilian environment. Seven herds were compared in their investigatory responses to a human and a ball. Breed differences were evident for approach and avoidance behavior, which had little relationship with one another. When reactions to the person and ball were compared, the responses were also breed specific but negatively correlated. Age took precedence over breed affiliation in investigating the human. The results were interpreted in a predator-prey context.

COMMUNAL SUCKLING IN WATER BUFFALO (Bubalus bubalis)

Abstract Communal nursing (an adult female allowing the offspring of another conspecific female to suckle) is a relatively frequent behavior in water buffalo (Bubalus bubalis). Fourteen lactating water buffalo cows and their nursing calves were observed at a Brazilian dairy after the cows had been milked. The two variables of greatest interest were solicitations of their own mothers and other cows by the calves, and acceptances of their own offspring and non-filial calves by the cows. Correlational analyses suggested three easily discriminable clusters of variables. Calves solicited and succeeded in suckling from their own mothers more often than they did from any other individual cow, but they solicited all other cows slightly more often than they did their own mothers. They were more likely to try to suckle other cows if they were rejected by their own mothers. Cows that had a high probability of accepting their own offspring tended to accept non-filial calves as well. Calves tended to maximize the total number rather than the probability of successful solicitations. Communal suckling was not reciprocal. Communal and filial suckling results from encounters between cows and calves performing under different motivational states.

Maternal recognition in Gyr (Bos indicus) calves

Abstract Gyr ( Bos indicus ) calves were studied in a milking shed where they were given the task of finding their biological mother among 46 cows tethered in two rows. Nearly all of the calves committed numerous errors. Younger calves were more likely than older ones to make incorrect discriminations. Errors tended to be in the direction of going to cows whose color was similar to that of the calfs mother. The calves color-matched their mothers phenotypes rather than their own. Responses interpreted as “errors” by human observers may be adaptive behavior for calves. Calves appear to employ elements of their mothers phenotypes in discriminating among individuals, regardless of their kinship.

Description and comparison of growth parameters in Chianina and Nelore cattle breeds

Weight data from birth to 18 months of age of Nelore and Chianina, both meat-producing cattle breeds, were analyzed. Data were corrected for significant effects of environment and utilized to estimate genetic parameters through the non-linear von Bertalanffy model. Average values found for growth parameters in Nelore were: mature weight (A), 312.87 kg; integration constant (B), 0.49; maturity rate (k), 0.13; age at inflection point (T(I)), 3.29 months; weight at inflection point (P(I)), 92.70 kg, and maturity interval (1/k), 8.04 months. For the Chianina animals, the values were 751.38 kg, 0.59, 0.10, 6.64 months, 222.63 kg, and 10.98 months, respectively. Nelore animals exhibited higher maturity rate, smaller maturity intervals, reaching mature weights younger than Chianina animals, although lighter than these at maturity. Heritability estimates presented low values, mainly for mature weight (0.093 and 0.212), age at inflection point (0.062 and 0.202), weight at inflection point (0.093 and 0.212) and maturity interval (0.057 and 0.309) (for Nelore and Chianina, respectively). The parameters mature weight and weight at inflection point presented positive genetic correlations with weights at different ages and with similar trends, increasing as age increased, in both breeds. Considering the development period analyzed, from birth to 18 months of age, the parameter maturity rate and the weights at different ages showed genetic correlations which increased until the weight at 150 and 205 days in Nelore and Chianina, respectively, and decreased from these ages on, and the genetic correlations among the parameter maturity interval and the weights at different ages were negative. They decreased until the weights at 150 and 205 days, respectively, in Nelore and Chianina, and increased from these ages on.

CALF CONTROL BY VOICE COMMAND IN A BRAZILIAN DAIRY

Abstract Brazilian dairymen present calves to their mothers at milking time as a stimulus for milk let-down. The calves fetched by calling them individually by name. Two crops of Gyr (Bos indicus) calves were observed experimentally. Their responses to the calls were consistent and statistically positive over both observations. Having strangers call the calves resulted in performance decrements, but positive responses still remained well above chance. Randomizing the calling orders had no deleterious effect. Positive responses and the number of calls necessary to elicit a positive response were independent, the latter being related to time of day and level of food deprivation. Calling the calves outside the milking context reduced positive responses dramatically, suggesting that the behavior was, in part, situation-specific. Cows solicit their calves through auditory signals “in nature”, and the husbandrymens successful vocal control was probably derived from that preexisting ethological system.

Behavioral observations in a capybara colony (Hydrochoerus hydrochaeris)

Abstract Capybaras ( Hydrochoerus hydrochaeris ), the largest living rodents, are receiving increasing interest as an economically attractive source of meat and hides in tropical America. An unmanaged capybara colony was studied in a setting adjacent to agricultural activities in Brazil. Preliminary notes were made on alarm responses to intruders, various aspects of flight behavior, and investigatory activity. The findings were mostly consistent with studies carried out by other investigators, suggesting that capybara behavior is similar from one region to another. The animals have potential for habituation to humans and are probably good candidates for domestication. Expanded commercial exploitation of capybaras could benefit their survival and welfare as well as contributing to the preservation of neotropical ecology in general.

Localization of genes modulating the predisposition to schizophrenia: a revision

The genetics of schizophrenia or bipolar affective disorder has advanced greatly at the molecular level since the introduction of probes for the localization of specific genes. Research on gene candidates for susceptibility to schizophrenia can broadly be divided into two types, i.e., linkage studies, where a gene is found near a specific DNA marker on a specific chromosome, and association studies, when a condition is associated with a specific allele of a specific gene. This review covers a decade of publications in this area, from the 1988 works of Bassett et al. and Sherrington et al. on a gene localized on the long arm of chromosome 5 at the 5q11-13 loci, to the 1997 work of Lin et al. pointing to the 13q14.1-q32 loci of chromosome 13 and to the 1998 work of Wright et al. on an HLA DRB1 gene locus on chromosome 6 at 6p21-3. The most replicated loci were those in the long arm of chromosome 22 (22q12-q13.1) and on the short arm of chromosome 6 (6p24-22). In this critical review of the molecular genetic studies involved in the localization of genes which modulate the predisposition to schizophrenia the high variability in the results obtained by different workers suggests that multiple loci are involved in the predisposition to this illness.

Efeito do pai do feto sobre as características produtivas e reprodutivas de vacas da raça pitangueiras

To estimate the magnitude of sire of fetus (SOF) effects on productive and reproductive traits in females of Pitangueiras breed, 2287 lactations of 618 cows, daughters of 82 bulls, mated with 68 sires were analyzed. The statistical analyses were made using LSMLMW program (Mixed Model Least Squares and Maximum Likelihood Computer Program). Sire of fetus (SOF) did not affect the milk production in the subsequent lactation, however its effect was significant for the percent fat and production, days open, gestation length and calving intervals. The estimates of SOF effects, expressed as a percentage of total variance, were .81, 1.67 and 6.43% for milk and percent fat and yield, respectively. This contribution on the reproductive traits was estimated in 7.76% for days open, 1.23% for gestation length and 7.57% for calving intervals. The genetic implications of the effect of SOF on the productive traits had small economic importance, however, on the reproductive performance, this effect was significant and measurable.

Genetic component in learning ability in bees.

Twenty-five bees, five from each of five hives, were trained to collect food at a table. When the bee reached the table, time was recorded for 12 visits. Then a blue and yellow pan was substituted for the original metal pan, and time and correct responses were recorded for 30 trips (discrimination phase). Finally, food was taken from the pan and extinction was recorded as incorrect responses for 20 visits. Variance analysis was carried out, and genetic variance was undetected for discrimination, but was detected for extinction. It is concluded that learning is very important for bees, so that any impairment in such ability affects colony survival.