The relationships between liveweight, growth from weaning to mating and conception rate of Bos indicus cross heifers in the dry tropics of north Queensland

1991 ◽  
Vol 31 (2) ◽  
pp. 139 ◽  
Author(s):  
VJ Doogan ◽  
G Fordyce ◽  
RK Shepherd ◽  
TA James ◽  
RG Holroyd
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Cohort Effect ◽  
Dry Season ◽  
Conception Rate ◽  
Dry Tropics ◽  
Factors Influencing ◽  
Conception Rates

Factors influencing the conception rates of 1332 Bos indicus cross maiden heifers in the dry tropics of North Queensland were studied between 1973 and 1986. The heifers, which were 112 and 314 Bos indicus (Brahman or Sahiwal) crosses with Bos taurus, were mated at 24-27 months of age over a 3-month period commencing in mid to late January. The effects of liveweights and growth rates on conception rate were initially assessed in separate models which always included cohort (year of branding group) as an additional factor. Cohort and liveweight at weaning, 18 months of age or the start of mating significantly (P<0.05) affected conception rate in maiden heifers. Response to liveweight was curvilinear, being marked for liveweights up to 125-150 kg at weaning, 200-225 kg at 18 months of age and 225-250 kg at the start of mating, with reduced response for greater liveweights. Liveweights of about 270 kg were indicated as targets at the start of mating in a typical year to achieve an 80% conception rate. Average daily gains during the post-weaning dry season and the dry season prior to mating did not influence conception rates after adjusting for cohort. Further analyses using models incorporating both liveweight and growth rate with and without the cohort effect gave indications that the significant cohort effect on conception rate was partly related to post-weaning dry season growth rate. F2 et seq. maiden heifers with low liveweights at either 18 months of age or mating had appreciably higher conception rates if they had gained weight in the post-weaning dry season, rather than losing weight.

Effect of pasture type and supplementary feeding on the reproductive performance of cattle in the dry tropics of north Queensland

1977 ◽  
Vol 17 (85) ◽  
pp. 197 ◽  
Author(s):  
RG Holroyd ◽  
PJ Allan ◽  
PK O'Rourke
Keyword(s):  
Reproductive Performance ◽  
Dry Season ◽  
Conception Rate ◽  
Wet Season ◽  
Lactating Cows ◽  
Dry Tropics ◽  
Stylosanthes Humilis ◽  
Native Pasture ◽  
Conception Rates ◽  
Townsville Stylo

A study was made over a four year period ( 1970-1 973) on the reproductive performance of cows grazing either native pasture stocked at 1 breeder 4.9 ha-1 or native pasture oversown with Townsville stylo (Stylosanthes humilis) and fertilized with superphosphate, stocked at 1 breeder 2.4 ha-1. Animals were supplemented on each pasture type with combinations of molasses, urea and phosphorus at various times of the year. Mating from September 1 to January 31 resulted in animals lactating during the dry season. At double the stocking rate, lactating cows on fertilized pastures had similar conception rates to those on native pasture. During a prolonged dry season, lactating cows on fertilized pasture had twice the conception rate and fewer required survival feeding. Urea compared with non-urea based supplements produced significant increases in conception rates of cows grazing native pasture especially during a dry year. Calves were born earlier, had shorter intercalving intervals and fewer cows had to be fed a survival ration when urea was available. On fertilized pasture, urea based supplements caused only a marginal increase in conception rate except in a dry year, when there was a significant increase. Over the four years, there was a diminishing response in the conception rate of lactating cows grazing native pasture and supplemented with phosphorus during the wet season compared with the control. On fertilized pasture, there was a variable but non-significant response. The addition of phosphorus either as a wet or dry season supplement to urea caused variable responses on each pasture type, but none differed significantly from that of urea.

The performance of Brahman-Shorthorn and Sahiwal-Shorthorn beef cattle in the dry tropics of northern Queensland. 3. Birth weights and growth to weaning

1993 ◽  
Vol 33 (2) ◽  
pp. 119 ◽  
Author(s):  
G Fordyce ◽  
TA James ◽  
RG Holroyd ◽  
NJ Beaman ◽  
RJ Mayer ◽  
...  
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Growth Rates ◽  
Bos Taurus ◽  
Growth Traits ◽  
Bos Indicus ◽  
Late Pregnancy ◽  
Growing Season ◽  
Late Generation ◽  
Calving Season

The birth weights and weaning weights of Bos indicus cross calves from 4 inter se mated herd groups in a dry tropical environment were studied. The calving season commenced in late October, about 2 weeks before the start of the pasture-growing season. Second and subsequent generations of 1/2 Brahman and 1/2 Sahiwal crosses and first backcross, and later generations of 3/4 Brahman and 3/4 Sahiwal crosses, were represented. The Bos taurus component of the crosses was primarily Beef Shorthorn. In general, Brahman crosses were heavier at birth and grew faster to weaning than Sahiwal crosses (P<0.05), with consequent advantages in weaning weights of 11 and 6 kg in first backcross and late generation crosses, respectively. There was a birth weight advantage (P<0.05) of 1/2 crosses over 3/4 crosses, which was eroded by the time of weaning. Superior growth rates of 3/4 crosses were primarily expressed in years with greater nutritional stress and appeared to be due to better adaptation to environmental stresses by the calf. The only difference between filial generations was the growth rate advantage (P<0.05) of F2 1/2 crosses over F3 1/2 crosses, apparently due to suckling of F1 and F2 dams, respectively. Males exhibited an 8% average advantage (P<0.05) over females for all weight and growth traits in late generation calves. Calves with mature dams were 1.8 kg heavier (P<0.05) at birth. This, along with their higher (P<0.05) preweaning growth rate (19-49 g/day), resulted in calves with mature dams being 4-10 kg heavier (P<0.05) at weaning than calves of young cows. Differences between years in birth weights and preweaning growth rates were <25% (P<0.05). Birth weight was affected by nutrition of the dam in late pregnancy (early calves were generally about 1 kg lighter than late calves), and growth of calves was higher in years when the pasture growing season commenced earlier.

Effects of different weaning strategies on postweaning growth rate, mortality and fertility of Bos indicus cross cattle

1990 ◽  
Vol 30 (1) ◽  
pp. 1 ◽  
Author(s):  
RG Holroyd ◽  
PK O'Rourke ◽  
R Tyler ◽  
HP Stephenson ◽  
GWJ Mason ◽  
...  
Keyword(s):  
Growth Rate ◽  
Bos Indicus ◽  
Dry Season ◽  
Subsequent Growth ◽  
Wet Season ◽  
Lower Growth ◽  
Treatment Groups ◽  
Pooled Data ◽  
Dry Tropics ◽  
Native Pastures

Three drafts of Brahman cross calves (phenotypically half to three-quarters Bos indicus) were either early weaned (EW) in April (mean age 5 months) or late weaned (LW) in July (mean age of 8 months). Their postweaning performance on native pastures in the dry tropics of North Queensland was monitored through to 2.5 years of age for females and 3.5 years for males. At late weaning, LW calves of both sexes were significantly (P<0.01) heavier than EW calves. Mean liveweight differences over the 3 drafts were 53.8 kg for males and 54.4 kg for females. From late weaning until final liveweight, EW animals partially compensated in growth and were on average 13.6 kg lighter at 3.5 years for males and 20.3 kg lighter at 2.5 years for females than LW animals. In draft 2, pregnancy rate at 2.5 years favoured LW heifers (P<0.05) by 38% units. Mortalities occurred only in the first dry season postweaning with 0, 5 (11.1%) and 5 (8.9%) deaths from poverty in the EW group in drafts 1 to '3 respectively but none in the LW group. Pooled data across treatment groups showed that older calves at weaning had lower growth rates during the first dry season but still had heavier final liveweights. Age at weaning did not influence subsequent growth rate in the first wet season or males in year 2 or year 3 postweaning.

Factors affecting mature size and dry-season weight loss in Bos indicus cross cows in northern Queensland

1988 ◽  
Vol 39 (6) ◽  
pp. 1169 ◽  
Author(s):  
G Fordyce ◽  
S Saithanoo ◽  
ME Goddard
Keyword(s):  
Growth Rate ◽  
Weight Loss ◽  
Adult Height ◽  
Bos Indicus ◽  
Dry Season ◽  
Factors Affecting ◽  
Weight Growth ◽  
Dry Tropics ◽  
Condition Score ◽  
Mature Size

Mature size and dry season weight loss affect the feed requirements, mortality rate and fertility of cows in the dry tropics. The aim of the work reported here was to study the effects of genotype and selection for growth rate on these parameters. The data consisted of: growth rate to 18 months; weight, height and condition score of cows over 5 years old; the change in these parameters during the dry season; and the past fertility of these cows. The cows were + or + bred Brahman of Sahiwal crosses. The Brahman crosses had the same growth rate but a higher mature weight than the Sahiwal crosses. The +-breds lost less weight during the dry season than the +-breds, implying a lower maintenance requirement. Growth rate to 18 monthswas correlated with adult height (r = 0.54) and weight (r = 0.58-0.68). Growth rate was correlated with dry season weight loss (r = 0.36), but only because weight loss was correlated with weight at the start of the dry season. After correcting for this starting weight, growth rate was not correlated with weight loss, and in fact growth rate was positively correlated with condition score late in the dry season (r = 0.17). Adult height was weekly correlated with dry season weight loss (r = 0.13). Past fertility was correlated with current fertility and with ability to maintain condition during the dry season.

The effect of spraying for buffalo fly (Haematobia irritans exigua) on infestations, growth rate and lesion development on Bos indicus × B. taurus cattle in the dry tropics of north Queensland

1984 ◽  
Vol 35 (4) ◽  
pp. 595 ◽  
Author(s):  
RG Holroyd ◽  
DJ Hirst ◽  
AW Merrifield ◽  
MA Toleman
Keyword(s):  
Growth Rate ◽  
Bos Indicus ◽  
Coat Colour ◽  
Dry Season ◽  
Wet Season ◽  
Lesion Development ◽  
Haematobia Irritans ◽  
Dry Tropics ◽  
Positive Correlations ◽  
June July

The effect of spraying for buffalo fly (Haematobia irritans exigua) on infestations, growth rate and lesion development on Bos indicus x B. taurus steers (18 months old) and bullocks (30 months old) were studied in the dry tropics of North Queensland. There were four consecutive drafts commencing between July and September and terminating the following June-July. Half of the animals were sprayed with 200 g/l fenvalerate to control buffalo flies. Treated animals carried, at most, a few flies. The size of the fly populations on the untreated animals varied with the seasons, with the most flies being recorded during the wet season. Light coloured animals carried fewer flies than those with darker colours and bullocks carried more flies than steers. Except for steers in one dry season, repeatabilities of fly counts were significant (P < 0.01). In steers, treatment had no significant (P > 0.05) effect on growth over the four treatment periods, although there were significant effects of treatment on growth in some intermediate periods. Treatment significantly (P < 0.05) affected bullock growth in two of the four years. Significant (P < 0.05) positive correlations were found between fly counts and growth rate in two years. Few lesions were recorded on treated animals. Lesion prevalence and size on untreated animals were generally not associated with fly counts, coat colour or growth rate.

scholarly journals Factors Influencing the Chlorine Susceptibility of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum

2003 ◽  
Vol 69 (9) ◽  
pp. 5685-5689 ◽  
Author(s):  
Joseph O. Falkinham
Keyword(s):  
Growth Rate ◽  
Mycobacterium Avium ◽  
Growth Phase ◽  
Growth Rates ◽  
Growth Stage ◽  
Tween 80 ◽  
Culture Conditions ◽  
C Cells ◽  
Mycobacterium Intracellulare ◽  
Factors Influencing

ABSTRACT The susceptibility of representative strains of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum (the MAIS group) to chlorine was studied to identify factors related to culture conditions and growth phase that influenced susceptibility. M. avium and M. intracellulare strains were more resistant to chlorine than were strains of M. scrofulaceum. Transparent and unpigmented colony variants were more resistant to chlorine than were their isogenic opaque and pigmented variants (respectively). Depending on growth stage and growth rate, MAIS strains differed in their chlorine susceptibilities. Cells from strains of all three species growing in early log phase at the highest growth rates were more susceptible than cells in log and stationary phase. Rapidly growing cells were more susceptible to chlorine than slowly growing cells. The chlorine susceptibility of M. avium cells grown at 30°C was increased when cells were exposed to chlorine at 40°C compared to susceptibility after exposure at 30°C. Cells of M. avium grown in 6% oxygen were significantly more chlorine susceptible than cells grown in air. Chlorine-resistant MAIS strains were more hydrophobic and resistant to Tween 80, para-nitrobenzoate, hydroxylamine, and nitrite than were the chlorine-sensitive strains.

Factors influencing growth of juvenile spruce grouse

1981 ◽  
Vol 59 (9) ◽  
pp. 1790-1795 ◽  
Author(s):  
Norman W. S. Quinn ◽  
Daniel M. Keppie
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
New Brunswick ◽  
Growth Rates ◽  
Egg Laying ◽  
Maternal Influence ◽  
Juvenile Growth ◽  
Factors Influencing ◽  
Differential Timing

The influences of date of hatch, and age and prelaying body weight of brood female on the growth rate of juvenile spruce grouse (Canachites canadensis) were studied in central New Brunswick in 1977 and 1978. Because of differential timing of hatch of broods of adult and yearling females, it was not clear whether a difference in juvenile growth rates during 5–14 days of age in 1977 was related to date of hatch, age of brood female, or both. Differences in juvenile growth rates within and between years apparently were not influenced by body weight of brood females prior to egg laying. Results suggest that posthatch factors are more important in determining growth rate than a prehatch or "maternal" influence.

Prediction of conception rate in extensive beef herds in north-western Australia. 2. Continuous mating and minimal management

1991 ◽  
Vol 31 (1) ◽  
pp. 9 ◽  
Author(s):  
PK O'Rourke ◽  
VJ Doogan ◽  
DJ Robertson ◽  
D Cooke
Keyword(s):  
Low Cost ◽  
Good Condition ◽  
Bos Indicus ◽  
Conception Rate ◽  
Low Fertility ◽  
Management Options ◽  
Conception Rates ◽  
Condition Score ◽  
Beef Herds ◽  
Survival Risk

Data from a continuously mated, unweaned and unsupplemented herd of 400 Bos indicus cross cows at 'Kidman Springs', from 1981-85, were used to develop statistical models for conception rate and pattern. At the annual muster in June, an average of 49% of cows were rearing a calf; 15% of these and 75% of those not rearing a calf were pregnant; and 54% conceived within the next 12 months. Cows non-pregnant in June had higher conception rates than pregnant ones (75 v. 33%), and among pregnant cows, those which had reared a calf had higher conception rates than those which had not (40 v. 26%). Cows that had not reared a calf were much heavier and in better condition in June than those that had, while pregnant cows were slightly heavier and better conditioned than non-pregnant ones. The effect of liveweight or condition score in June on subsequent conception rate was consistent across years, reproductive classes and cow ages. Conception rates responded linearly to increases in liveweight, in the range 250-400 kg, by 11 percentage points up to October and by 24 points up to June. Similar linear responses to condition score in the range poor-good condition were 8 points by October and 15 points by June. Reproductive wastage was high, with 20% of cows diagnosed pregnant in June failing to rear their calf to branding. Low-cost management options to improve reproductive efficiency should be aimed at reducing nutritional stress and improving seasonal nutrition. To improve on the norm of a calf every second year in this environment, the class of cows not rearing a calf but pregnant and expected to calve by December has the greatest potential to conceive in consecutive years and should be segregated for preferential management. Conversely, aged cows not rearing a calf have comparatively low fertility and non-pregnant younger cows not rearing a calf are likely to be a survival risk following an out-ofseason conception. Both groups should be culled.

Prediction of conception rate in extensive beef herds in north-western Australia. 1. Seasonal mating and improved management

1991 ◽  
Vol 31 (1) ◽  
pp. 1 ◽  
Author(s):  
PK O'Rourke ◽  
VJ Doogan ◽  
TH McCosker ◽  
AR Eggington
Keyword(s):  
Low Cost ◽  
Good Condition ◽  
Dry Season ◽  
Conception Rate ◽  
Gravid Uterus ◽  
Practical Implementation ◽  
Lactating Cows ◽  
Conception Rates ◽  
Return On Capital ◽  
Condition Score

Statistical models for conception rate were developed using data collected at a mid dry season (August-September) muster from a controlled-mated and supplemented herd of 900 Brahman cross cows at Mt Bundey from 1980-84. Average conception rates were 74% for maidens, 25% for first-lactation cows, 51 % for 4-10-year-old lactating cows, 54% for >10-year-old lactating cows and 96% for non-lactating cows. Although year effects dominated, they were partially explained by severity of the dry season and were consistent across levels of the other factors. Pregnant maiden heifers weighed 13 kg more than non-pregnant ones at the end of mating, after allowing for the weight of the fetus and gravid uterus. Conception rate of first-lactation cows was not affected by month of calving, adjusted mid dry season weight or condition score, possibly because of narrow ranges in these factors based on selection. For mature lactating cows the main effects on conception rate were month of calving (+11% for September to -16% for December or later), previous lactation (+6% for having reared a calf), adjusted mid dry season weight (-16% for <300 kg to +9% for >350 kg) and condition score (-17% for backward and store to +16% for good condition). Corresponding effects for aged lactating cows were +14% for September to -19% for December or later calving, +8% for previously rearing a calf, and -24% for backward store and store to +23% for good condition cows. The high conception rates for non-lactating cows corresponded with high liveweights and condition scores. A low cost, practical implementation of these models is based on previous lactation status and condition score in the mid dry season, with pregnancy diagnosis added at the next stage. Reproductive classes could be segregated on this basis for improved management and nutrition and to gain an economic return on capital invested in cattle control.

Effects of weaning and supplementation on performance of Brahman cross cows and their progeny

1988 ◽  
Vol 28 (1) ◽  
pp. 11 ◽  
Author(s):  
RG Holroyd ◽  
GWJ Mason ◽  
ID Loxton ◽  
PT Knights ◽  
PK O'Rourke
Keyword(s):  
Birth Weight ◽  
Pregnancy Rate ◽  
Management Practices ◽  
Bos Indicus ◽  
Mortality Rates ◽  
Dry Season ◽  
Early Weaning ◽  
Monoammonium Phosphate ◽  
Dry Tropics ◽  
Native Pastures

In a 3-year study in the dry tropics, 2 management practices of dry season supplementation of cows and early weaning of calves were concurrently examined as possible techniques for improving reproductive, liveweight and survival performance of Brahman cross cows (phenotypically 1/2 - 3/4 Bos indicus) grazing native pastures. Cows were either supplemented with a drylick mixture of salt, urea and sulfur (DL) commencing in July for 4-6 months; supplemented with a crisis mixture of salt, urea, grain, molasses, meatmeal and monoammonium phosphate (CM) in the latter part of the dry season; or were not supplemented (C). Mating commenced in January, and calves were either early weaned (EW) at the end of mating in April (mean age of 5 months) or late weaned (LW) in July (mean age of 8 months). Supplements and weaning treatments had little effect on cow liveweight, except between early weaning and late weaning when EW cows gained more or lost less weight (mean advantage of 30.8 kg) than LW cows and were heavier (mean advantage of 44.8 kg) than LW cows at late weaning time. Across all years, 1.4, 2.1 and 4.2% of cows in DL, CM and C groups respectively died from malnutrition or required survival feeding; whereas, in the second and third years, mortality rates due to malnutrition were 0.7 and 2.1% in EW and LW groups respectively. Neither supplement nor weaning treatments had any significant effect on lactating cow pregnancy rates, although data pooled across treatments showed that liveweights at various stages pre-mating were correlated with pregnancy rate. Supplementation or weaning treatments did not influence calving date or birth weight, but LW calves grew significantly faster (mean advantage of 0.52 kg/day) between early weaning and late weaning and were significantly heavier (mean advantage of 57.4 kg) at late weaning than EW calves.

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