Brahman Cattle Research Articles

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. III.* Growth on previously unexposed animals

Length measurements were used to compare the growth of the parasitic stages of Boophilus microplus on previously unexposed Brahman (Bos indicus) and Shorthorn (B. taurus) cattle. Growth curves based on the length measurements were constructed. Growth was slower on Brahmans than on Shorthorns during the first 24 hr of larval and nymphal instars. After the first 24 hr, the growth rates of larvae, and of nymphs, during feeding to engorgement were the same on the rump and belly regions of both species of cattle. Larvae and nymphs engorged more slowly on the brisket than they did on the rump and belly regions of the Brahmans. The surface skin temperature was lower on the brisket of the Brahmans. On the basis of change in the length of the tick during development on Brahmans, 16 age categories were established, so that the length of the tick may be used to estimate the ages of ticks in populations on Brahman cattle. Age categories were also defined for ticks which had been processed in formalin and hot alkali. __________________ *Part II, Aust. J. Agric. Res., 29: 395 (1978).

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. II.* The dynamics of resistance in previously unexposed and exposed cattle

The dynamics of host resistance to Boophilus microplus was investigated in previously unexposed and exposed Brahmans, and in previously unexposed Shorthorn cattle. The animals were infested each day with 1000 larvae, and the development of resistance was monitored by counting the number of female ticks which engorged. The previously unexposed cattle showed an initial period of susceptibility (phase I) which was followed by a period in which most animals developed degrees of resistance (phase II), and which stabilized in some animals (phase III). The duration of phase I was shorter in Brahmans, and they developed higher levels of resistance (phase III). In contrast, previously cxposed Brahmans manifested phase III levels of resistance immediately on infestation. The results provide further evidence that resistance to B. microplus in Brahmans, as well as in European breeds, is acquired rather than innate. __________________ *Part I, Aust. J. Agric. Res., 26: 1073 (1975).

Reproductive Performance and Crossbreeding Angus, Brahman and Charolais Cattle

Reproductive Performance and Crossbreeding Angus, Brahman and Charolais Cattle

Difference between the Hb C variants in Brahman and in indigenous Southern African cattle breeds

SummaryHaemoglobin polymorphism in Brahman cattle and seven Southern African cattle breeds was investigated by means of starch gel electrophoresis. A difference was found between the migration rates of the Hb C of Brahman cattle and that of the indigenous Southern African cattle breeds, showing that these are actually two separate variants. We suggest that the faster migrating type, which occurs in Brahman cattle, should be called Hb C, while the slower migrating type of the Southern African breeds, should be called Hb I.A comparison of the migration of the α and β chains of all the variants we encountered, including foetal haemoglobin, was carried out by means of starch gel electrophoresis in urea at acid and alkaline pH levels. Evidence was found of a difference in mobility of the non‐a chains of haemoglobin A, B, C, I and F at different pH levels while no difference was detected in the migration rate of their respective α chains. These results confirm the theory that genetic variation is restricted to the non‐α chain of bovine haemoglobin.Progeny studies on 225 families confirm that the Hb I variant is allelic to Hb A and Hb B variants. The gene frequencies have been calculated on the basis that Hb I and Hb C are allelic at the β locus. The distribution of the different phenotypes is in accordance with this theory, assuming that the populations obey Hardy‐Weinberg equilibrium.

The performance of Santa Gertrudis, Sahiwal, Brahman and cross-bred animals in the intermediate savannahs of Guyana: 2. Birth weight and preweaning performance

SUMMARYData collected over a period of 11 years at the Ebini Livestock Station in the intermediate savannahs of Guyana were analysed to determine the effect of breed or cross, sire, sex, year and season of birth of calf, and age and length of calving interval of the dam on weights at birth and at 4, 8 and 12 months of age, in Santa Gertrudis, Sahiwal and Brahman cattle. The heritability of body weights at the different ages was estimated.

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. I. Responses of previously unexposed cattle to four infestations with 20,000 larvae

Four purebred Brahman and four beef Shorthorn cattle which had not previously been exposed to Boophilus microplus were infested four times with 20,000 B. microplus larvae. On first infestation, the yield of engorged female ticks on all animals was about 25% of the larvae applied. Aftcr three further infestations, the mean yield of engorged females on the Brahmans decreased to 7.5% whereas there was no decrease in the yield of ticks on the Shorthorns. On the Brahman cattle. development of larvae to engorged females took 1–2 days longer and the engorged females weighed less. However, there was no difference in the reproductive index of female ticks engorged on either Brahmans or Shorthorns. Increases in rectal temperatures occurred in all cattle 15–17 days after the first infestation and in some cattle on days 6–7 as well as on days 15–17 after reinfestation. It was concluded that resistance to B. microplus is an acquired phenomenon in Brahman cattle.

Growth performance of Brahman and Charolais × Brahman cattle in a tropical environment

Weight per day of age at weaning (175 days) and at 553 days, and post-weaning gain were collected from 159 high grade Brahman and 35 Charolais x Brahman crossbreds on a commercial property in Central Queensland and analysed by the least squares method. The primary reason was to measure the effect of Charolais infusion on high grade Brahman cattle. CharolaisxBrahman cattle were 0.280 kg and 0.168 kg heavier per day of age at weaning and 553 days respectively, and gained 0.126 kg day-1 more during the post-weaning period than the Brahmans (all P < 0.005). Older dams weaned heavier calves than younger dams (P < 0.01), but the differences were non-significant at 553 days and for post-weaning gain. Males were significantly heavier per day of age at weaning and 553 days, and gained more during the post-weaning period. The regression on day of birth was highly significant (P < 0.005) for weight per day of age at 175 days, but not at 553 days.

Comparative reproductive performance of Brahman and Santa Gertrudis cattle in a hot humid environment 2. Factors affecting calving interval

SUMMARYOver a 15-year period 1011 calving intervals from 187 Brahman (B) cows and 687 calving intervals from 146 Santa Gertrudis (SG) were examined. Year of calving significantly affected intervals in both breeds. Season of calving and parity of dam were both important in SG. Longer intervals were seen in B than SG (437 v. 406 days). Repeatability of calving interval was low (< 0·02). The average life-time calving interval was significantly related to total calf production in that cows with shorter mean intervals had more calves in their lifetime.

Comparative reproductive performance of Brahman and Santa Gertrudis cattle in a hot humid environment 1. Fertility and descriptive statistics

SUMMARYIn a 15-year period (1956-1970) data were available from 192 Brahman cows exposed to bulls on 1409 occasions (1199 calvings) and from 155 Santa Gertrudis cows exposed 907 times (847 calvings). All were mated by natural service in the same herd in Cuba. Calving percentage and net calf crop significantly favoured the Santa Gertrudis with overall means of 92·7 and 85·3% for the two traits respectively. Parity, lactation status and year of calving significantly affected calving percentage with significant year × breed and status × parity interactions. Lactation status, year of calving, breed × year and status × parity interactions also affected net calf crop. Calf mortality was 6·41% in Brahmans and 5·64% in Santa Gertrudis but more of the latter breed were stillborn (41·7 v. 16·9% of all deaths). There were no breed effects on age at first or last calving, age at culling or calves per cow which were 38·5 months, 117·1 months, 130·1 months and 6·62 calves in Brahmans and 39·3, 111·5, 123·2 and 6·58 respectively in Santa Gertrudis. Twinning percentage was low (under 0·4%) and male births high (53·54%) in both breeds. Some 30% of cows lost at least one calf prior to weaning during their lifetime.

Boophilus microplus: Digestion of hemoglobins by the engorged female tick

When the cattle tick Boophilus microplus, after dropping from its host, was maintained at 27 C, the digestion of hemoglobins in the gut proceeded at a steady rate and was virtually complete by the 13th day. The rate was essentially the same whether the ticks were strains susceptible (Yeerongpilly) or resistant (Biarra) to organophosphorous compounds or whether the hosts were British breed, Brahman or banteng cattle, or buffalo. Ferrihemoglobin appeared in the gut contents and hematin was deposited. About 10% of the hematin released from the hemoglobin was transferred to the eggs and from them to the larvae. Translucent ticks, sometimes found on heavily infested hosts and referred to as “serum” ticks, had about half the normal hemoglobin content.

Ciodrin Spray and Dust Formulations for Horn Fly, Haematobia irritans, Control on Brahman and Crossbred Cattle

A study was conducted to determine the effectiveness of Ciodrin (alpha-methylbenzyl 3-hydroxycrotonate dimethyl phosphate) when applied as a 0.5% spray or as a 3% dust in a self-applicating dust bag for control of horn flies, Haematobia irritans (Linnaeus), on Brahman and crossbred cattle at Belle Glade, Florida. The 3% Ciodrin dust reduced horn fly populations 49% on Brahman and 43% on crossbred steers. A weekly application of 0.5% Ciodrin spray reduced horn fly populations 86% on Brahman and 88% on crossbred steers. Untreated Brahman cattle averaged 78% fewer horn flies per steer than untreated crossbred cattle. Brahman cattle treated with a 3% Ciodrin dust bag had 80% fewer flies per steer than crossbred cattle on the same treatment. Brahman cattle had 75% fewer flies than crossbred cattle when both were treated with 0.5% Ciodrin spray. Brahman and crossbred cattle on the same treatment were confined to the same pasture during the study. All treatment and breed differences were significant at the 1% level.

Comparison of thyroid hormone levels in Hereford and Brahman cattle.

Blood samples were collected at 28-day intervals over a period of 10 months from March through December from six Hereford and six Brahman cattle, three of each breed and sex. The blood serum was analyzed for level of circulating thyroid hormones by Sephadex column chromatography employing 131I-labelled T3. Significant differences were found for breed and sex effects. The Herefords had a significantly higher percent uptake than Brahmans, indicating that the Herefords had a lower level of circulating thyroid hormones. The heifers had a significantly lower percent uptake than the bulls, indicating that heifers had a higher level of circulating thyroid hormones.

Environmental physiology in the sub-tropics. I. Effect of continuous environmental stress on some hematological values of beef cattle.

Hematological values were determined in 24 beef cattle under two different sets of environmental conditions. Three bulls and three heifers of each of the Hereford and Brahman breeds were used in each treatment. Twelve animals were housed at 11 months of age in a chamber at an ambient temperature of 21 C and with a relative humidity of 65%. Another 12 animals of the same age were housed at 32 C, 95% R.H. All animals remained under these conditions for a period of 1 year. Blood was collected every 28 days and analyzed for erythrocyte number, leukocyte number, hemoglobin, packed cell volume, mean corpuscular hemoglobin and mean corpuscular volume. Brahman cattle when compared with Hereford cattle had significantly higher values for erythrocyte numbers and packed cell volume. High temperature-high humidity treatment significantly reduced mean corpuscular volume and mean corpuscular hemoglobin. No significant effects due to the temperature treatment were found in erythrocyte numbers, leukocyte numbers, packed cell volume or blood hemoglobin concentration. However, a slight reduction in hemoglobin concentration was found in animals under a temperature and humidity stress. Significant interactions, found in some parameters, indicated the need to consider the sex as well as the breed of the animals when experiments of this nature are carried out with beef cattle of Asiatic and European origin.

Brahman cattle in a temperate environment:I. Live-weight gains and carcass characteristics

SUMMARYA study was made of the live-weight gains of four ¾-bred Brahman and four purebred Hereford steers over a 12-month period. At 950 lb live weight each animal was slaughtered, after which the carcass characteristics of the two breed types were compared.The Herefords showed the highest live-weight gains over the whole year but during autumn, when nutritional levels were poor, the Brahmans had an advantage in average daily gain.Although both breed types varied greatly in body conformation, there was little appreciable difference in weight distribution of joints on the carcass. A higher dressing percentage was observed in the Brahmans, this being attributed to their smaller alimentary tracts. The Brahmans had a greater carcass muscle and smaller carcass fat content than the Herefords. The necessity for fat trimming of the Hereford carcasses reduced their calculated retail value index to a level below that of the Brahmans in a market which discriminated against excess fat.Thus it was concluded that even in a temperate climate, Brahman cattle can have a place in improving productive efficiency. Apart from the heterosis developed in crossbreeding, benefits should flow from the Brahmans superiority on poor pastures and the improved production of lean meat on their carcasses.

Brahman cattle in a temperate environment:II. Adaptability and grazing behaviour

SUMMARYOn seven separate occasions during a year, 24-h studies were made on the grazing behaviour of four ¾-bred Brahman and four purebred Hereford steers in the cool temperate New England region of northern N.S.W.Although both breeds spent approximately the same time grazing, the Brahmans ruminated for shorter periods and thus had a lower ruminating time to grazing time ratio than the Herefords. No signs of cold stress were observed in either breed even though the dry bulb temperature frequently fell below freezing point. However, the Herefords sought shade more than the Brahmans when the black body temperature exceeded 32°C.It is concluded that a climate such as that of New England, where winters are cold, should in no way adversely affect the performance of Brahman-type cattle, as judged by their behaviour.

Lung fibrinolytic activity and bovine high mountain disease.

SummaryThe concentrations of plasminogen activator, trypsin inhibitor, and tissue thromboplastin in lungs of different breeds of cattle have been determined. Brahman cattle (Bos indicus) has a higher average concentration of plasminogen activator than breeds of normal cattle (Bos taurus). There are large individual variations in concentrations of trypsin inhibitor. It is suggested that these variations could explain differences in susceptibility to high mountain disease.

Reproductive behavior of Bos inducus females in a subtropical environment. II. Gestation length in Brahman cattle.

Dates of breeding and birth dates of Brahman calves were obtained from two ranches in south Florida. The length of 1323 gestation periods was calculated. Errors due to the nature of this field study are discussed. The mean gestation length of 1048 gestation periods which were between 271 and 310 days was 292.8 days. The frequency distribution for the length of gestation periods is reported as well as the results of a variance analysis for location, sire and sex effects. While there was no difference between locations, sex and sire differences contributed significantly to the total variance, showing that the genotype of the calf affects the length of time it is carried in utero. The results are discussed in relation to the literature for Bos indicus and Bos taurus cattle.

Heritability of fertility in Brahman and crossbred cattle.

The calving records of a purebred Brahman herd and a crossbred foundation herd of Brahman-Shorthorn breeding were evaluated for genetic influences on cow fertility. Observations were coded one (1) and zero (0), respectively, for cows which calved and those which failed to calve. Heritability estimates for birth rate by paternal half-sib correlations based on single records of 3-year-old first record cows and 4-year-old second record cows were 0.31 and 0.21, respectively, in the Brahman herd and 0.63 and 0.56 in the crossbred herd, for an average of 0.42 for the four estimates obtained from single records. Estimates from the paternal half-sib correlation of average lifetime records were 0.39 for both herds. The regression of lifetime average of the daughter on the lifetime average of her dam yielded heritability estimates of 0.54 and 0.25 for the two herds, respectively.

Avaliação do consumo de forragens e determinação de excreção de fezes, em zebu (Bos Indicus), através dos indicadores: óxido crômico e cromogênios

An experiment was conducted in order to study the applicability of marker techniques - chromic oxide and chromogens - for the purpose of determining the fecal output and measurement of feed intake by Brahman cattle (Bos indicus). The chromic oxide was administered once daily in gelatine capsules. Fecal samples were taken at 6 A.M., noon and 6 P. M. and were totally collected during days, as well. Chromogens expressed in units per gram of roughages or feces (dry basis) and chromium oxide per cent of fecal dry matter, were determined on all the samples. The chromic oxide concentration of feces taken at 6 A.M., noon, 6 P.M. and bulked on seven consecutive days, as well as the mixed feces representing the total amount voided during 7 days period provided no accurate estimates of the total fecal output when the SMITH and REID (’55) equation was applied. The coefficients of correlation between the fecal output values determined conventionally and the estimates secured according SMITH and REID ('55) equation, were + 0.75 and + 0.89 for the total collection and the pooled 6 A.M. and 6 P.M. collection, respectively. Then, after using the SMTHI and REID ('55) equation, were proposed two other regression equations in order to correct the values and to obtain accurate estimates of the total fecal output in Brahman cattle. After correcting the total fecal excretion values it was possible to compute accurate levels of the dry matter intake employing the REID et al ( '50 - '52) equations. The modified procedure suggested by REID et al ('52) for calibrating the method of measuring the chromogens concentration, in the roughages, presented, for the Coleman Universal, model 14, the equation as follows: Y = 54.99-26.92 log X, where: Y = concentration of chromogens in the roughages, expressed in units per 100 ml of extract, X = per cent of transmitted light. In relation with the excretion pattern of feces, as small as + 3.2 g of chromic oxide administered daily, in capsule form showed reduced variation - 8% - among animals. The data suggested also that since the concentrate feeds contain very small quantities of chromogen absorving light at 405 mμ, large error was encountered when the chromogen content was determined on the whole ration. Then, more accurate results may be obtained if the chromogens are determined only on the roughage.

Comparative Gas Carrying Capacities of Blood from Brahman and Hereford Cattle

The carbon dioxide and oxygen contents, oxygen capacity and percent oxygen saturation of venous blood are presented for 36 Hereford (Bos taurus) and 36 Brahman (Bos indicus) female bovines. The animals were divided according to two breeds, three ages (calves, heifers and mature cows) and two levels of dietary protein (100% and 50% of the N.R.C. recommended allowances). Venous blood from Hereford cattle had significantly more carbon dioxide than that from Brahmans. Calf blood had less oxygen than blood from heifers or cows. Oxygen capacity expressed on both the total volume and body weight basis decreased while the percent oxygen saturation of blood increased with age. A 50% reduction in dietary protein did not affect the blood gases studied when expressed in volumes percent. However, when oxygen capacity was expressed on a body weight basis, animals receiving the recommended protein allowance had a significantly lower oxygen capacity. This effect was probably the result of differences in body weight and composition.