Physiological reasons for heterosis in growth of Bos indicus × Bos taurus

1987 ◽  
Vol 109 (2) ◽  
pp. 213-230 ◽  
Author(s):  
J. E. Frisch
Keyword(s):  
Sexual Maturity ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Live Weight ◽  
High Growth ◽  
Environmental Stresses ◽  
Growth Potential ◽  
Plasma Testosterone ◽  
Resistant Parent ◽  
Weight Gains

SummaryBy comparing growth rates of Brahman (B), Hereford × Shorthorn (HS), their reciprocal F1, hybrid (F1BX), their Fn hybrid (FnBX) and an F1 Charolais × Brahman hybrid (Fl CH x B) in environments that differed in their levels of stresses that affected growth, it was shown that heterosis for growth realized in any environment arose because of heterosis in its underlying determinants, namely growth potential and resistance to environmental stresses. Growth potential of the F1 BX was similar to that of the better parent (HS) whilst resistance to environmental stresses was similar to or approached that of the more resistant parent (B). This combination of high growth potential and high resistance to environmental stresses enabled the F1 BX to outgain both parents at all levels of environmental stress above zero. However, some or all of the heterosis in both growth potential and resistance to environmental stresses was lost in the Fn BX. Thus, although previous selection for increased live-weight gain should have favoured the Fn BX, they realized lower live-weight gains than the Fl BX in all environments and lower live-weight gains than the parental breeds in all but intermediate environments.Because the breeds differed in both determinants of growth, the magnitude of estimates of heterosis for realized growth was dependent on the environment in which it was measured. A figure depicting this interaction was constructed.Comparative estimates were also made of the rate of approach to sexual maturity of bulls of each breed. The F1 BX had similar values to the better parent (HS) for both scrotal circumference and plasma testosterone concentrations. However, the Fn BX had values that were intermediate to those of the parental breeds.Generally, gains of the -F, CH × B exceeded those of all other breeds in all environments but their rate of approach to sexual maturity was slower than that of the F1 BX.

The incidence and effect of poisoning with Lantana camara in different cattle breeds

1984 ◽  
Vol 102 (1) ◽  
pp. 191-195 ◽  
Author(s):  
J. E. Frisch ◽  
C. J. O'Neill ◽  
H. M. Burrow
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Live Weight ◽  
Environmental Stresses ◽  
Practical Significance ◽  
Detectable Effect ◽  
Parasite Control ◽  
Cattle Ticks ◽  
Breed Differences ◽  
Selection Of

SummaryThe incidence of lantana poisoning and its effect on mortality, growth rate and fertility were recorded from 1975 to 1982 in seven lines of Bos taurus and Bos indicus cattle and their crosses.Two Bos taurus Hereford × Shorthorn (HS) lines had higher incidences of poisoning and higher mortalities after poisoning than the Bos indicus based breeds.During the period of poisoning, live–weight gains of affected animals of all breeds were reduced but subsequent recovery was rapid. Lantana poisoning had no detectable effect on the fertility of animals affected at least 10 months prior to their first mating, irrespective of breed.Parasite control influenced the incidence of poisoning and mortality in genetically similar groups of HS cattle. This observation, when combined with the between-breed relationships between the incidence of lantana poisoning and susceptibility to environmental stresses suggests that the marked breed differences in susceptibility to lantana poisoning stem from differences in resistance to other environmental stresses, including cattle ticks. This offers little scope for selection of animals that are resistant to lantana poisoning per se but has practical significance in lantanainfested regions.

Genetic parameters for tropical beef cattle in northern Australia: a review

1993 ◽  
Vol 44 (2) ◽  
pp. 179 ◽  
Author(s):  
GP Davis
Keyword(s):  
Genetic Parameters ◽  
Production Systems ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Genetic Correlations ◽  
Environmental Stresses ◽  
Northern Australia ◽  
Weighted Mean ◽  
Weaning Weight ◽  
Reproduction Traits

This paper reviews published estimates of genetic parameters for traits of growth, reproduction and resistance to environmental stresses for Bos indicus and Zebu derived breeds in northern Australia. Most published estimates of heritabilities for growth and reproduction traits were higher for tropically adapted breeds in northern Australia than for Bos taurus breeds in temperate Australia. Weighted mean estimates of heritabilities for the direct component of weaning weight were 39% for the Brahman breed and 30% for Zebu-derived breeds in northern Australia compared with 13% for Bos taurus breeds in temperate areas of Australia. Mean estimates for the maternal component of weaning weight were 5, 24 and 13% respectively. Mean heritabilities for yearling and 550 day weights for Zebu derived breeds in northern Australia (24 and 25%) were similar to those for Bos taurus breeds in temperate areas, though estimates for Brahmans were higher (39 and 39%). Published estimates of heritabilities of later weights (700 and 900 days), which are most relevant to northern Australian production systems, were rare but averaged between 32 and 45% for Zebu-derived breeds and Brahmans. Weighted mean heritability for female calving success was 14% and for realised bull fertility was 5%. Published estimates of heritabilities of scrota1 circumference averaged 31%, and testosterone response to GNRH stimulation was 52%. Heritabilities of resistance to various environmental stresses were all moderate with weighted means between 20 and 34%. Genetic correlations between growth, reproduction and resistance to environmental stresses are also reviewed. There appears to be predictable variation in estimates of parameters between breeds in different environments which is related to level of resistance to environmental stresses, and this is likely to affect the prediction of breeding values for cattle in northern Australia.

An analysis of growth of different cattle genotypes reared in different environments

1984 ◽  
Vol 103 (1) ◽  
pp. 137-153 ◽  
Author(s):  
J. E. Frisch ◽  
T. E. Vercoe
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Environmental Stresses ◽  
Growth Potential ◽  
Gastrointestinal Helminths ◽  
Treatment Groups ◽  
Survival And Growth ◽  
Different Levels ◽  
High Growth Potential

SummaryCalves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.

The effect of treadmill slope on the relationship between heart rate and energy expenditure in cattle walking on treadmills

1986 ◽  
Vol 106 (3) ◽  
pp. 433-436 ◽  
Author(s):  
Jennifer C. Sneddon
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Ambient Temperature ◽  
Bos Taurus ◽  
Regression Line ◽  
Bos Indicus ◽  
Live Weight ◽  
Percentage Increase ◽  
The Relationship ◽  
Working Heart

SummaryTwo steers (Bos indicus and Bos indicus x Bos taurus) were acclimatized to an ambient temperature of 30 °C before working at this temperature on two treadmills (gradients 0 and 6°) for 2 h (one on each treadmill) whilst carrying a load equivalent to 10% of body weight. The study was then repeated at an ambient temperature of 15 °C. The effect of variation between animals, ambient temperature and rate of energy expenditure were tested on the linear regression model EEw = A PHR + B (where EEw is the energy expenditure (w/kg0·75) and PHR is the percentage increase of working heart rate over resting heart rate).Animal and ambient temperature had no significant effect on the model. The gradient of the regression line was significantly greater (P < 0·01) when the animals were expending energy at the higher rate (about 30 W/kg live weight0·75) than when they were expending energy at the lower rate (about 14 W/kg live weight0·75).

Effect of undernutrition and refeeding on digestion in Bos taurus and Bos indicus in a tropical environment

1998 ◽  
Vol 67 (1) ◽  
pp. 49-58 ◽  
Author(s):  
P. Grimaud ◽  
D. Richard ◽  
A. Kanwé ◽  
C. Durier ◽  
M. Doreau
Keyword(s):  
Dry Matter ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Live Weight ◽  
Apparent Digestibility ◽  
Low Level ◽  
Particle Retention ◽  
Maintenance Requirements ◽  
Energy Maintenance

AbstractThe effect of underfeeding and ref eeding on digestion was studied in Bos taurus and Bos indicus cows. Eight nonlactating cows, four B. taurus and four B. indicus (live weight 156 kg and 207 kg respectively) were first given a forage-based diet at a level above energy maintenance requirements for 4 weeks (3·65 and 4·66 kg dry matter (DM) per day respectively for B. taurus and B. indicus). They were then restricted at a low level of intake for 2 months (1·83 and 2·33 kg DM per day respectively for B. taurus and B. indicus) and finally refed at the first level for 2 months. Digestion measurements were made before the underfeeding period, at 3 and 8 weeks of underfeeding and at 3 and 8 weeks ofref eeding. Organic matter apparent digestibility decreased with underfeeding and increased with refeeding (0·637, 0·591, 0·652, 0·692 and 0·669 in B. taurus and 0·674, 0·560, 0·580, 0·698 and 0·692 in B. indicus, respectively 1 week before, 3 and 8 weeks after underfeeding, and 3 and 8 weeks after refeeding). This lower apparent digestibility at low level of intake was not expected either by ruminal particle retention time, which increased when intake decreased, or by measurements ofmicrobial activity: DM degradability measured in situ and ruminal particle size did not vary with level of intake. An effect of the length of underfeeding and refeeding was seen: the apparent digestibility tended to increase after several weeks of undernutrition and was higher after refeeding than before underfeeding. No difference was observed between the two genotypes.

Food intake and live-weight gain comparisons of Bos indicus and Bos taurus steers on a high plane of nutrition

1968 ◽  
Vol 10 (4) ◽  
pp. 373-380 ◽  
Author(s):  
A. Rogerson ◽  
H. P. Ledger ◽  
G. H. Freeman
Keyword(s):  
Weight Gain ◽  
Feed Intake ◽  
Dry Matter ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Live Weight ◽  
Indigenous Cattle ◽  
Live Weight Gain ◽  
Maintenance Requirements ◽  
Maturity Degree

1. The voluntary dry-matter and water intakes of indigenous and exotic cattle on high plane rations have been compared under similar conditions of management.2. At similar live weights, exotic cattle have a much higher feed intake relative to maintenance than indigenous cattle.3. Water intake was closely related to dry-matter intake, irrespective of live weight, and varied only very slightly between the two types of cattle.4. Exotic cattle were more than twice as efficient as indigenous cattle in converting feed into live-weight gain. It is suggested that this is largely a reflection of the increased feed intake, relative to maintenance requirements.5. Stage of maturity, degree of fatness and their relation to conversion efficiency are discussed.

The effect of supplementation with Leucaena leucocephala and maize bran on voluntary food intake, digestibility, live weight and milk yield of Bos indicus × Bos taurus dairy cows and rumen fermentation in steers offered Pennisetum purpureum ad libitum in the semi-humid tropics

1995 ◽  
Vol 60 (1) ◽  
pp. 13-23 ◽  
Author(s):  
R. W. Muinga ◽  
J. H. Topps ◽  
J. A. Rooke ◽  
W. Thorpe
Keyword(s):  
Food Intake ◽  
Milk Yield ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Live Weight ◽  
Rumen Fermentation ◽  
Napier Grass ◽  
Pennisetum Purpureum ◽  
Rumen Degradation ◽  
Maize Bran

AbstractAn experiment was carried out to evaluate dairy performance and rumen fermentation from a forage-based diet supplemented with Lucaena leococephala (leucaena) and maize bran. Bos indicus (Ayrshire/Brown Swiss) х Bos taurus (Sahiwal) cattle were offered Pennisetum purpureum (napier grass) ad libitum either unsupplemented (N) or supplemented on a dry-matter (DM) basis with 1 kg (LL) or 2 kg leucaena (LH) or 2 kg leucaena together with 1 kg DM maize bran (LHM). Food intake, milk yield, diet apparent digestibility and nitrogen balance were measured using eight cows (mean live weight 384 (s.d. 41) kg in two 4х4 Latin squares. Rumen fermentation was measured using four rumen fistulated steers (mean live weight 352 (s.d. 12) kg in a 4 х 4 Latin square. Performance was recorded during the last 7 days of each 21-day experimental period. Supplementation increased food intake (6·3, 7·6, 7·9 and 8·7 kg DM per day; P < 0·01; s.e.d. 0·24) and milk yield (5·1, 5·4, 5·5 and 6·5 kg/day; P < 0·01; s.e.d. 0·28) for N, LL, LH and LHM respectively. Supplemented diets tended to be more digestible compared with napier grass as the sole food (organic matter apparent digestibility coefficients 0·54, 0·55, 0·57 and 0·57; s.e.d. 0·020; N, LL, LH and LHM, respectively) and N balance increased progressively with supplementation.Supplementation progressively increased rumen ammonia-nitrogen concentrations in steers and the rate of rumen degradation of napier grass increased when leucaena (diets LL and LH) was offered. The results suggest that supplementation of napier grass with leucaena increased DM intake owing to increased ammonia concentrations and rates of napier degradation in the rumen. Supplementation of the forage diet with 1 kg DM maize bran did not significantly reduce the rumen degradation of napier grass and increased the molar proportions of propionate which may have increased the efficiency of utilization of metabolizable energy and therefore milk production.

The effects of supplementation with Gliricidia sepium or Leucaena leucocephala forage on intake, digestion and live-weight gains of Bos taurus × Bos indicus steers offered napier grass

1996 ◽  
Vol 63 (3) ◽  
pp. 381-388 ◽  
Author(s):  
S. A. Abdulrazak ◽  
R. W. Muinga ◽  
W. Thorpe ◽  
E. R. Ørskov
Keyword(s):  
Leucaena Leucocephala ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Live Weight ◽  
Basal Diet ◽  
Gliricidia Sepium ◽  
Napier Grass ◽  
Apparent Digestibility ◽  
Weight Changes ◽  
Microbial Nitrogen

AbstractTwo experiments were carried out to evaluate the effect of incremental levels of Gliricidia sepium (gliricidia) and Leucaena leucocephala (leucaena) on forage intake, diet apparent digestibility, microbial nitrogen supply and live-weight changes in cattle. In each experiment, 20 intact and five fistulated crossbred steers (Bos taurus × Bos indicus) were used. Napier grass basal diet was offered ad libitum alone or supplemented with 7·5, 15, 22·5, or 30 g dry matter (DM) per kg metabolic body weight (M075) gliricidia (experiment 1) or leucaena (experiment 2). In experiment 1, total DM intake increased but not significantly with gliricidia supplementation (5·2, 5·1, 5·2, 5·4, 5·7 (s.e.d. 0·21) kg/day) while intake of napier grass was depressed linearly (5·2, 4·7, 4·5, 4·3, 4·2 (s.e.d. 0·21) kg/day; P < 0·05). In experiment 2, supplementation with leucaena increased the total DM intake linearly without depressing the intake of napier grass (5·2, 5·8, 6·2, 6·6, 6·7 (s.e.d. 0·31) kg/day; P < 0001 and 5·2, 5·3, 5·3, 5·3, 5·0 (s.e.d. 0·21) kg/day respectively). Neither gliricidia nor leucaena supplementation affected the apparent digestibility of the diet or in sacco DM degradation characteristics of the forages. Rumen ammonia and live-weight gain were increased linearly (P < 0·05) by supplementation from 130 to 215mg/l (experiment 1) and 75 to 113mg/l (experiment 2), from 306 to 478 g/day (experiment 1) and from 538 to 850 g/day (experiment 2), respectively. However, since the responses were linear, further experiments are required to quantify the responses to higher levels of these legume supplements.

Effects of the ratio of silage to concentrates in the diet on the performance and carcass composition of continental bulls

2000 ◽  
Vol 70 (1) ◽  
pp. 171-179 ◽  
Author(s):  
D. C. Patterson ◽  
R. W. J. Steen ◽  
C. A. Moore ◽  
B. W. Moss
Keyword(s):  
Live Weight ◽  
High Growth ◽  
Basal Diet ◽  
Ammonia Nitrogen ◽  
Carcass Composition ◽  
Growth Potential ◽  
Lean Tissue ◽  
Important Conclusion ◽  
Grass Silage ◽  
Carcass Parameters

AbstractA total of 45 continental bulls (1/2 Blonde d'Aquitaine/3/8 Charolais) were used in a continuous design randomized-block experiment, to examine the effects of the ratio of silage to concentrates in the diet on growth and carcass parameters. The proportions of concentrates in the five diets were 0·26, 0·40, 0·55, 0·68 and 0·75 (DM basis). The basal diet was grass silage with D value 730 g/kg and ammonia nitrogen per unit total nitrogen 86 g/kg. The mean initial and final live weights were 467 and 651 kg respectively, with a mean carcass weight of 384 kg. The digestibility of energy was not affected by the proportion of concentrates in the diet. The rates of live weight, carcass and separable lean tissue gain tended to reach a plateau at the higher concentrate proportions, while the rate of separable fat tissue gain increased linearly with increase in concentrate proportion. The separable lean content of the carcass was linearly and negatively related to the proportion of concentrates, with a predicted decrease of’10 g/kg for an increase in concentrate proportion of 0·16. Separable fat content was also linearly related to the proportion of concentrates, with a predicted increase of 10 g/kg for each 0·196 increase in proportion of concentrates. The absence of any effect of concentrate proportion on the content of saleable meat in the carcass was considered to reflect the high growth potential of the animals. An important conclusion was that 0·99 of the asymptote value for lean tissue gain was attained at a concentrate proportion of 0·52 and that 0·95 of the maximum rate of gain was obtained at the relatively low concentrate proportion of 0·39, therefore indicating that finishing bulls of this type can perform to a high level on diets which are predominately based on grass silage.

The utilization of dietary energy by steers during periods of restricted food intake and subsequent realimentaion

1977 ◽  
Vol 88 (1) ◽  
pp. 11-26 ◽  
Author(s):  
H. P. Ledger ◽  
A. R. Sayers
Keyword(s):  
Food Intake ◽  
Digestive Tract ◽  
Bos Taurus ◽  
Weight Maintenance ◽  
Bos Indicus ◽  
Live Weight ◽  
Progressive Increase ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Energy Concentration

SUMMARYGroups of Bos indicus (Boran) and Bos taurus (Hereford) × Bos indicus steers were kept at constant live weights of 185, 275 and 450 kg for periods of up to 24 weeks. Maintenance of these live weights was achieved by control of the daily ration of a diet having an energy concentration of 10·477 MJ metabolizable energy (ME)/kg d.m. AS time progressed it was noted that less of the diet had to be fed daily to maintain constant live weight. Body composition of steers slaughtered at 0, 12 and 24 weeks showed that the live weights had been maintained by the compensating effect of empty body weight gains and digestive tract content-weight losses.No significant differences were found between slaughter groups for the energy values of the boneless carcass meat nor the internal deposits of empty digestive tract, omental and mesenteric fat. It was therefore concluded that there had been a progressive increase in the efficiency of energy utilization for the production of edible meat.The percentage reduction of daily food intake from 3 to 24 weeks necessary to maintain the prescribed live weights ranged from 51·8% for the 185 kg Borans to 17·9% for the 450 kg ¾ Boran × Hereford cross-breds.Comparison with published estimates for maintenance of live weight showed that after 24 weeks at constant live weight the 185 and 275 kg Borans and the 450 kg ¾ Borans needed 50·5, 37·9 and 34·2% less and the 275 kg Hereford × Boran cross-breds and 450 kg ¾ Herefords 40·8 and 37·9% respectively less food than estimated.Correction for age effects on the fasting metabolic rates of the 185 and 275 kg weight groups reduced the difference between theoretical and actual maintenance requirements from 50·5, 37·9 and 40·8% to 37·3, 29·3 and 33·8% respectively.Attention is drawn to the need to differentiate between the live-weight maintenance needs of fast and slow growing animals which may be of similar live weights but differing ages.

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