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.

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.

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.

17 THE EFFECT OF EXOGENOUS PROGESTERONE ON CONCEPTION RATE OF COOLED COWS DURING THE SUMMER AND AUTUMN

2009 ◽  
Vol 21 (1) ◽  
pp. 108 ◽  
Author(s):  
D. Wolfenson ◽  
E. Friedman ◽  
Y. Lavon ◽  
Z. Roth
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Visual Observation ◽  
Conception Rate ◽  
Uterine Disease ◽  
Variable Effect ◽  
Lactating Cows ◽  
Condition Score ◽  
Commercial Farms ◽  
Exogenous Progesterone

Dairy cows exhibit low concentrations of plasma progesterone during the summer. The effect of exogenous progesterone supplementation postinsemination (AI) in the summer on conception is equivocal. Moreover, the variability among studies in thermal stress severity contributes to the variable effect of exogenous progesterone on summer fertility. This study examined the effect of supplementing exogenous progesterone post-AI during the summer and autumn on conception rate of lactating cows that were efficiently cooled during the hot season. The study was conducted in Israel on 2 commercial farms of high-milk-producing cows, yielding, on average, 41.3 kg of milk day–1 around AI (124 days postpartum). These farms were equipped with efficient cooling systems along the feeding line and in the holding area. Mean body temperatures during the afternoon and evening hours in summer (air temperature and relative humidity of 30 to 32°C and 41 to 57%) were 39.1 ± 0.1°C, with a peak value of 39.5°C. Cows at first, second, or third AI that were inseminated after estrus (Day 0; detected by visual observation and computerized pedometric system; Afimilk, Israel) from July to August (summer) or September to October (fall) were included in the study (n = 377 cows). Treated cows (n = 181 cows) were fitted with an intravaginal device containing progesterone (CIDR) on Day 5 ± 1 after AI for 12 days; the device was removed on Day 17. Administration of the CIDR increased progesterone concentration by 2.3 ng mL–1 (P < 0.05). Conception rates were analyzed by a logistic regression procedure. Overall, the CIDR treatment increased conception rate by 6% compared with controls (39 v. 33%; NS). Day of CIDR insertion tended to affect conception rate (43, 39, and 34% for Days 4, 5, and 6, respectively; NS). The CIDR treatment significantly increased, compared with the control (+23%, P < 0.05), the conception rate of cows with a low body condition score at peak lactation (49.3 v. 26.6%). Similarly, the CIDR significantly increased (+22%, P < 0.05) the conception rate of cows that exhibited a uterine disorder at parturition (46.3 v. 24.6% in untreated control cows). The CIDR treatment also increased conception rate (NS) in the fall (+13%) in mature cows (+8%) and in the first AI (+12%). Similarly, cows treated with a CIDR before Day 120 postpartum, or cows yielding less than 40 kg of milk day–1 exhibited a numerically higher (+8%; NS) conception rate. Results indicated that exogenous progesterone administered post-AI increases conception during the summer and autumn in efficiently cooled cows during the hot months. The most beneficial effect was documented in cows that had been diagnosed as having a uterine disease postpartum, and in those that exhibited a low body condition score.

Conception rates of beef cattle in Botswana following synchronization of oestrus with cloprostenol

1980 ◽  
Vol 30 (1) ◽  
pp. 61-67 ◽  
Author(s):  
N. G. Buck ◽  
D. Light ◽  
A. D. Makobo
Keyword(s):  
Beef Cattle ◽  
Conception Rate ◽  
Breeding Methods ◽  
Crossbred Cattle ◽  
Lactating Cows ◽  
Valuable Method ◽  
Conception Rates ◽  
Natural Service ◽  
Selection Of

ABSTRACTIn three trials conducted in 3 successive years, Africander, Brahman, Tswana, Tuli and crossbred cattle were injected intramuscularly with 500 jug of cloprostenol on two occasions 11 days apart to synchronize oestrus. The cattle were inseminated 72 and 96 h after the second injection. Controls of the same breeds were exposed to natural service for a period of 22 days. In all trials the conception rate to natural service was significantly higher (P < 0·01).Conception rates to both breeding methods were highest in Tuli and crossbred cattle and lowest in the Africander and Brahman. Non-lactating cows showed higher fertility than suckling cows and maiden heifers.Vasectomized bulls used in one trial were shown to be useful in the selection of breeding cows suitable for oestrus synchronization. Further studies are justified to maximize the benefits of a potentially valuable method of breeding beef cattle in ranching conditions.

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.

scholarly journals Pocket MUSE: an affordable, versatile and high-performance fluorescence microscope using a smartphone

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yehe Liu ◽  
Andrew M. Rollins ◽  
Richard M. Levenson ◽  
Farzad Fereidouni ◽  
Michael W. Jenkins
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
Consumer Electronics ◽  
Practical Implementation ◽  
The Novel ◽  
Point Of Care Diagnostics ◽  
Optical Module ◽  
Optical Configuration ◽  
User Friendly

AbstractSmartphone microscopes can be useful tools for a broad range of imaging applications. This manuscript demonstrates the first practical implementation of Microscopy with Ultraviolet Surface Excitation (MUSE) in a compact smartphone microscope called Pocket MUSE, resulting in a remarkably effective design. Fabricated with parts from consumer electronics that are readily available at low cost, the small optical module attaches directly over the rear lens in a smartphone. It enables high-quality multichannel fluorescence microscopy with submicron resolution over a 10× equivalent field of view. In addition to the novel optical configuration, Pocket MUSE is compatible with a series of simple, portable, and user-friendly sample preparation strategies that can be directly implemented for various microscopy applications for point-of-care diagnostics, at-home health monitoring, plant biology, STEM education, environmental studies, etc.

Evaluation of intrauterine insemination of sheep with frozen semen: effects of time of insemination and semen dose on conception rates

1991 ◽  
Vol 53 (1) ◽  
pp. 89-96 ◽  
Author(s):  
R. C. F. Findlater ◽  
W. Haresign ◽  
R. M. Curnock ◽  
N. F. G. Beck
Keyword(s):  
Intrauterine Insemination ◽  
Field Application ◽  
Conception Rate ◽  
Laparoscopic Technique ◽  
Motile Sperm ◽  
Treatment Groups ◽  
Frozen Semen ◽  
Significant Difference ◽  
Conception Rates ◽  
Serum Gonadotropin

ABSTRACTThe field application of a laparoscopic technique to permit intra-uterine insemination of ewes with frozen-thawed semen was examined in two trials, conducted over successive years, to (i) determine the optimum time of insemination relative to sponge removal/pregnant mares's serum gonadotropin (PMSG) injection and (ii) establish the relationship between semen dose and conception rate. Pooled semen was used in both trials, and each involved > 900 ewes in a number of commercial flocks.Maximum conception rates were achieved when insemination was conducted between 54 h and 60 h after sponge removal/ PMSG injection. However, there was no significant difference in conception rate when motile sperm numbers were reduced from 52·2 × 106to 13·0 × 106 motile sperm per uterine horn.The overall conception rates (pooled over flocks and treatment groups) were 56% and 58% for the two trials, with a wide degree of variation between flocks in both cases (45% to 79% for trial 1 and 45% to 69% for trial 2). However, there was evidence for consistent differences in conception rates between the six flocks involved in both years of the trials.

scholarly journals Growth of Brahman cross heifers to 2 years of age in the dry tropics

2019 ◽  
Vol 59 (1) ◽  
pp. 148
Author(s):  
Geoffry Fordyce ◽  
Kerri Chandra
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Dry Season ◽  
Protein Supplementation ◽  
Negative Effects ◽  
Northern Forest ◽  
Forest Region ◽  
Supplementation Period ◽  
Condition Score ◽  
Height Gain

Growth of 1368 Brahman cross heifers from 6 year cohorts was monitored over the 2 years post-weaning in Australia’s northern forest, a low-animal-growth dry tropical environment. Heifers weighing 47–266 kg at weaning were managed in groups weighing &lt;100 kg, 100–149 kg, 150–199 kg, and &gt;199 kg during the post-weaning dry season. Weaner heifers were allocated to receive 300 g/day of a protein meal during the dry season or to basic nutritional management to sustain health. Heifers in three cohorts were allocated to first mating at 1 or 2 years of age, in four cohorts to vaccination against androstenedione, and in a small proportion of two cohorts to ovariectomy post-weaning. Growth was highly variable between seasons and years; average cohort liveweight by the start of 2-year-old mating was 256–319 kg. Heifer groups not receiving protein supplementation gained –16 to 21 kg (2 kg average) during 6-month dry seasons, and 49–131 kg (101 kg average) during wet seasons to reach an average of two-thirds of mature liveweight (445 kg) and 95% of mature hip height (1350 mm) by the start of mating at 2 years. Average body condition score (1–5) fluctuated by 1–2 units between seasons. Hip height gain continued, irrespective of season, commencing at ~0.60 mm/day at 6 months of age, and decelerating by ~0.00075 mm/day through to 2.5 years of age. Standard errors of predicted means across analyses were ~0.015 for average daily weight gains, 0.4 mm for average monthly height gain and 0.06 score units for average seasonal body condition score change. Post-weaning dry-season supplementation increased gains in liveweight, height and body condition score by an average of 0.1 kg/day, 0.1 mm/day and 0.5 units, respectively, during the supplementation period. Periods of poor nutrition or high nutritional demand secondary to reproduction suppressed daily gains in liveweight and hip height, at which times body condition score was also reduced. Subsequent to this, partial to full compensation occurred for all measures. Ovariectomy had negative effects on growth. Androstenedione vaccination had no effect on growth. The main conclusion is that heifer growth in Australia’s dry tropical northern forest region is highly variable between seasons and years, thus limiting significant proportions of some cohorts from reaching target weights for mating at 2 years of age, even after compensatory growth.

Reproductive performance of Shorthorn and Brahman crossbred cows in the dry tropics of north Queensland

1979 ◽  
Vol 19 (98) ◽  
pp. 276 ◽  
Author(s):  
RG Holroyd ◽  
PK O'Rourke ◽  
PJ Allan
Keyword(s):  
Reproductive Performance ◽  
Experimental Period ◽  
Ovarian Activity ◽  
Gestation Length ◽  
Variable Effect ◽  
Crossbred Cows ◽  
Lactating Cows ◽  
Dry Tropics ◽  
Significant Difference ◽  
Conception Rates

A study was made (1 970 to 1973) of the reproductive performance of Shorthorn and Brahman crossbred cows grazing pasture in the dry tropics of north Queensland. Breed had a variable effect on the conception rates of lactating cows, with Brahman crossbreds having significantly higher (P < 0.05) conception rates in the first year. The two breeds had similar conception rates in the following year. In the third year, overall conception rates of both breeds were reduced due to a prolonged dry season, with Shorthorn cows having significantly higher (P < 0.01) conception rates than Brahman cows. However, during this dry period, twice as many Shorthorn cows required survival feeding as did Brahman cows. Calving rates followed conception rates closely, prenatal loss in each breed being low. In all years, Shorthorns had significantly earlier (P < 0.05) calving dates than Brahmans. The interval from calving to first recorded ovarian activity was significantly longer (P < 0.05) in Brahman cross than in Shorthorn cows in only one of the three years. There was no significant difference between breeds for the interval from first recorded ovarian activity to conception, but this interval decreased with increasing age of the cow. Breed had a variable effect on gestation length. Brahman cows were generally heavier each year in April and in better condition throughout the experimental period than Shorthorn cows.

scholarly journals Prevalence and risk factors of mastitis in dairy cows

1970 ◽  
Vol 26 (2) ◽  
pp. 54-60 ◽  
Author(s):  
MA Rahman ◽  
MMU Bhuiyan ◽  
MM Kamal ◽  
M Shamsuddin
Keyword(s):  
Risk Factors ◽  
Dairy Cows ◽  
Dairy Farms ◽  
Clinical Mastitis ◽  
Dry Season ◽  
The Other ◽  
Wet Season ◽  
Lactating Cows ◽  
California Mastitis Test ◽  
Control Programmes

Identification of risk factors is important for the design of control programmes for mastitis in cows. Information about farms and management was collected at a farm visit. California Mastitis Test (CMT) was performed to assess sub-clinical mastitis, and cows, udder and milk were examined for clinical mastitis. A total of 347 lactating cows from 83 farms in the dry season (November - February) and 388 lactating cows from 89 farms in the wet season (June - October) were studied. The overall prevalence of mastitis was 19.9% and 44.8% in dry and wet seasons, respectively. The prevalence of mild mastitis was 17.3% and 40.7%, whereas that of moderate mastitis was 2.6% and 4.1% in dry and wet seasons, respectively. The prevalence of mastitis was higher (P<0.01) in wet than in dry season. On average, 18.7% quarters had mastitis during the wet season and 6.9% in the dry season. In the dry and wet seasons, respectively, 63.9% and 11.2% had completely dry floors, and the prevalence of mastitis was 22.6% and 30.0%. On the other hand, 88.8% and 36.1% of 83 farms had partly or completely wet and soiled floor and the prevalence of mastitis was 40.0% and 59.5% in the dry and wet seasons, respectively. Udder cleanliness, milk yield and peri-parturient diseases significantly (P<0.01) increased the risk of mastitis. The prevalence of mastitis is regarded as quite high. Dry and clean floor to keep cow's udder and teat clean would help control mastitis in the dairy farms of Bangladesh. DOI: 10.3329/bvet.v26i2.4951 Bangl. vet. 2009. Vol. 26, No. 2, 54-60

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