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.

23 EFFECTS OF THE NUMBER OF SERVICES FERTILITY IN DAIRY COWS

2011 ◽  
Vol 23 (1) ◽  
pp. 118 ◽  
Author(s):  
M. Yamaguchi ◽  
M. Tanisawa ◽  
H. Koyama ◽  
S. Takahashi ◽  
O. Dochi
Keyword(s):  
Dairy Cows ◽  
Conception Rate ◽  
Low Fertility ◽  
Chi Square ◽  
The Third ◽  
Total Percentage ◽  
Conception Rates ◽  
Service Conception ◽  
Chi Square Test ◽  
Rectal Palpation

In recent years, reproductive performance of dairy cows has been declining worldwide, especially among cows of high genetic merit for milk production. The cause of the low fertility may considerably vary across countries and is probably multifactorial. This problem remains unsolved. Further, the first-service conception rate of dairy cows has remarkably decreased worldwide. The number of services required for conception has increased due to the low fertility in dairy cows. However, there are few reports about the relationship between conception rates and the number of services in the current dairy cows. The objective of this study was to investigate whether the number of services affects the conception rates of dairy cows. Data concerning the conception rates was obtained for 8386 Holstein cows from 40 commercial dairy herds in eastern Hokkaido, Japan, from 2006 to 2009. The diagnosis of pregnancy was confirmed by rectal palpation between 30 and 45 days after insemination. The average interval between calving and the first-service was 87.3 days. The average milk yield was 8500 kg. Number of conducting services was from the first to the seventh service. The conception rate was analysed using chi-square test. The results are presented in Table1. The conception rate from the first to the seventh service was 40.2 to 54.0%. The conception rate at the first service was significantly low (40.2%); however, the conception rates did not significantly differ after the second-service. A similar tendency was observed during each year. Moreover, the total percentage of conceptions from the first to the third service was 83.8%. The average number of services per conception was 2.2. The results of this study indicate that the first service yielded the lowest conception rates. The conception rates after the second service did not significantly differ. Moreover, ∼84% of the dairy cows became pregnant between the first service and the third service. However, this result shows that ∼16% of the dairy cows in the herds were repeat breeding. In order to improve fertility, it is necessary to study the factors that affect the first-service conception rates of dairy cows. Moreover, to improve the conception rate of dairy cows, it is important to elucidate the cause of these problems. Table 1.The number and percentage of dairy cows conceiving at each of the services for consecutive services

A comparison of once- and twice-yearly weaning of an extensive herd in northern Australia

1997 ◽  
Vol 37 (3) ◽  
pp. 287 ◽  
Author(s):  
R. M. Sullivan ◽  
P. K. O'Rourke ◽  
J. A. Neale
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Cost Effective ◽  
Conception Rate ◽  
First Year ◽  
Wet Season ◽  
Growth And Survival ◽  
Breeding Herd ◽  
Beef Herds ◽  
Native Pastures

Summary. Continuous mating is common in northern Australian beef herds. The resulting calves are born throughout the year making weaning and herd management difficult. Calves born late in the wet season do not reach suitable liveweight for weaning until late in the year. Low liveweight and poor feed conditions make management of these animals for subsequent turnoff or breeding more difficult. We recorded the growth and survival of all progeny and reproductive performance of heifers from 2 groups of 250 Bos indicus-Bos taurus-cross cows grazing native pastures at Kidman Springs, Northern Territory, for 5 years from July 1985. Calves were weaned in June only (W1) or June and October (W2). Unweaned calves remained with their dams until June the following year and heifers entered the breeding herd as 2 year olds. Calves weaned in June (WJ) were heaviest (157.1 kg; P<0.05) but gained least (84.6 kg; P<0.05) over the following year. Unweaned (UW) calves were lighter (51.1 kg; P<0.05) at branding time, in June, than those weaned in October (WO; 66.8 kg). However, they gained more weight (144.5 v. 112.4 kg; P<0.05) over the following year than WO calves because of a superior wet season growth rate, so that WO calves were lightest (P<0.05) at the yearling muster. Mortality rates of all calf groups were low (2.5%). Liveweight at branding and liveweight gain to yearling stage affected whether heifers subsequently joined the breeding herd. More (P<0.05) heifers from WJ joined the herd than from WO and UW groups. Overall, 63.6% of heifers were selected as replacement breeders (no difference between W1 and W2). Bull control was difficult and many heifers (48%) conceived before the planned start of mating. Cumulative conception rate was 91.3% by 30 months post-branding. In the first year, 60% of heifers mated were confirmed pregnant, but reproductive losses of 25.6% from pregnancy diagnosis to branding contributed to a branding rate of 44.9%. The conception rate of heifers when lactating was 18.6%. Mortality during the first year in the herd was 11.7%. In general, WJ heifers had lower mortalities, higher conception, calving and weaning rates, and higher conception rates when lactating than WO or UW heifers. Animals weaned in October were identified as the most difficult group to manage because of lower liveweight as 2 year olds compared with WJ and UW calves. This affected the numbers of heifers suitable for joining. Cost-effective management systems are needed to improve growth rates or delay onset of oestrus in these animals.

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 Effects of delaying the removal of the intravaginal progesterone device by 24 h in the 5d Co-synch protocol in heifers

2021 ◽  
Author(s):  
Aitor Fernandez-Novo ◽  
Sergio Santos-Lopez ◽  
Jose Luis Pesantez-Pacheco ◽  
Natividad Pérez Villalobos ◽  
Ana Heras-Molina ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Fixed Time ◽  
Conception Rate ◽  
Reproductive Efficiency ◽  
Beef Heifers ◽  
Serum Progesterone ◽  
Dairy Heifers ◽  
Condition Score ◽  
Commercial Farms ◽  
Beef Herds

Abstract Background In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. This study explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72 h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In Experiment 1, we examined whether such a modified protocol would provide an acceptable, total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56 h protocol (5dCo56; n = 10), the standard 5d Co-synch 72 h protocol (5dCo72; n = 17), or the modified 5d Co-synch 72 h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). Heifers were considered synchronized (TSR) if serum progesterone value > 1.0 ng/mL and the corpus luteus (CL) was detectable by ultrasonography on Day 5, if progesterone < 1.0 ng/mL and at least one follicle had a diameter > 8 mm on Day 7.5, and if progesterone > 1.0 ng/mL and CL was detectable on Day 15. In Experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72 h or 6d Co-synch 48 h protocol and conception rate (CR) studied. Results In experiment 1, the three protocols in dairy heifers led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72) and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (P = 0.907). Heifer age, body condition score or stress score did not significantly affect conception rate. Conclusions These results suggest that delaying removal of the intravaginal progesterone device by 24 h during the standard 5d Co-synch 72 h protocol provides satisfactory results without reducing reproductive efficiency of heifers.

An investigation into the relationship between the metabolism of pyruvate in bull spermatozoa and fertility

1956 ◽  
Vol 48 (2) ◽  
pp. 153-159 ◽  
Author(s):  
G. Glew
Keyword(s):  
Metabolic Response ◽  
Conception Rate ◽  
Low Fertility ◽  
High Fertility ◽  
Practical Application ◽  
Experimental Conditions ◽  
Conception Rates ◽  
The Mean ◽  
Dairy Bulls ◽  
The Relationship

1. Two hundred and ninety-one samples of semen from seventy-four dairy bulls in use at seven artificial insemination centres and one bull-rearing centre were tested and graded according to the type of metabolic response under the experimental conditions described by Melrose & Terner (1953).2. Conception rates of bulls were obtained from the breeding records based on not less than 150 first inseminations. Since the mean conception rates of centres varied, the fertility of each bull was assessed in relation to the mean conception rate of the centre at which the bull was standing. Bulls were considered of ‘high’ fertility when their conception rates were above, and of ‘low’ fertility when their conception rates were below a dividing line 5% below the mean conception rate of the centre.3. A highly significant relationship (P < 0·001) was found between the groups of the metabolic responses and the fertility levels of the bulls. The practical application of the test in the assessment of the potential fertility of individual bulls is discussed.

7 ARTIFICIAL INSEMINATION IN BOS INDICUS WITH SEMEN IN SIMULTANEOUS POOL OF MULTIPLE BULLS

2010 ◽  
Vol 22 (1) ◽  
pp. 161
Author(s):  
J. R. S. Torres-Júnior ◽  
J. A. T. Souza ◽  
M. I. S. Silva ◽  
J. S. Costa ◽  
G. S. Lima ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Sao Paulo ◽  
Conception Rate ◽  
São Paulo ◽  
Conventional Dose ◽  
Conception Rates ◽  
Time Required

The duration of spermatic viability in the female reproductive system in cattle is 18 to 24 hours. Therefore, the time required for sperm capacitation in different bulls demonstrated to be highly variable and may affect the adequate amount of capacitated sperm within an optimal window of time for fertilization. The aim of this study was to evaluate the conception rate in Nelore cows inseminated with semen from a single bull compared with semen from a pool of 3 bulls (Fertility Plus®, ABS Pecplan, Minas Gerais, Brazil). On a random day of the estrous cycle (Day 0), 400 Nelore multiparous cows received a progesterone intravaginal device (1 g of P4, DIB®, Intervet/Schering-Plough, Cotia, Brazil) plus 2mg of estradiol benzoate (i.m. Estrogin®, Farmavet, São Paulo, Brazil). At the time of P4 device withdrawal (Day 8), 150 (ig of d-cloprostenol (i.m. Preloban®, Intervet/Schering-Plough), 1 mg of estradiol cypionate (i.m. ECP®, Pfizer, Brazil), and 300IU of eCG (i.m. Folligon®, Intervet/Schering-Plough) were administered. At 48 to 52 h after implant removal, all cows were fixed-time inseminated (FTAI). Then, cows were homogeneously distributed based on the semen used for FTAI in 4 groups: CONV1 (conventional dose of semen from bull 1), CONV2 (conventional dose of semen from bull 2), CONV3 (conventional dose of semen from bull 3), FERT (pool of semen from bulls 1, 2 and 3 homogeneously mixed in a single dose). Both conventional and Fertility Plus batches of semen contained a total dose of 30 × 106 spermatozoa. For pregnancy diagnosis, an ultrasonographic (CHISON 500VET, USP Brasil Eletromedicina, São Paulo, Brazil) examination was performed 30 days after the FTAI. Data were analyzed using the GENMOD procedure of SAS (SAS Institute, Cary, NC, USA). There was no interaction between treatment and body condition score [using a 1 (very thin) to 5 (very fat) point scale] or AI technician. The conception rates for CONV1, CONV2, CONV3, and FERT were, respectively, 40/101 (39.6%)b, 50/99 (50.5%)ab, 46/99 (46.5%)ab, 54/101 (53.5%)a; P < 0.05. In addition, the mean of conventional v. Fertility Plus treatments presented conception rates of 136/299 (45.5%) v. 54/101 (53.5%), respectively (P = 0.14). No significant statistical differences were observed between treatments. However, this trial showed that the utilization of the new Fertility Plus technology increased the overall conception rate by 8.0%. This probably implicates a complementary effect among semen samples and provides a greater time of sperm viability in oviduct. Also it provides evidence of the individual variation in capacitation time of bulls used for composition of the pool. Pooled semen of multiple sires may improve the reproductive performance at AI in cattle and increase the potential of the beef industry to produce pregnancies and born calves.

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 AUTUMN AND WINTER LAMBING STRATEGIES IN NORTHLAND

1986 ◽  
pp. 81-87
Author(s):  
W.G.K. Andrewes ◽  
A.O. Taylor
Keyword(s):  
Low Cost ◽  
Breeding Programme ◽  
Management Options ◽  
Mating Ability ◽  
Ewe Lambs ◽  
Sheep Production ◽  
Autumn And Winter

Progress in the development of autumn and winter lambing systems in Northland is described. Both involve split flock lambing in which 30 or 15% of ewes lamb in autumn or winter respectivelv, the remainder in spring. Using progesterone priming, a high ram to ewe ratio (10%) and ram management, 80.90% of ewes joined lamb over 2 cycles. Winter lambing using cull ewes is simple and does not require a breeding programme. Ewes and their lambs can be sent to the meat works from September. For low cost lamb production with present breeds, autumn lambing requires a breeding programme to develop spring mating ability. Heavyweight(18kg)carcasses can be produced early in the killing season. Autumn born replacement ewe lambs consistently averaged 40kg before their first summer. Both systems offer more flexibility in sheep production on farms and in processing and marketing. Keywords: Autumn lambing, winter lambing, split lambing, management options, extending killing season, heavyweight lambs production

scholarly journals Design and construction of low-cost respiration chambers for ruminal methane measurements in ruminants

2017 ◽  
Vol 8 (2) ◽  
pp. 185 ◽  
Author(s):  
Jorge Rodolfo Canul Solis ◽  
Angel Trinidad Piñeiro Vázquez ◽  
Jeyderl Israe Arceo Castillo ◽  
José Alayón Alayón Gamboa ◽  
Armín Javier Ayala Burgos ◽  
...  
Keyword(s):  
Methane Production ◽  
Low Cost ◽  
Bos Indicus ◽  
Mass Action ◽  
Pennisetum Purpureum ◽  
Air Conditioner ◽  
Tropical Regions ◽  
In Vivo Measurement ◽  
Design Construction

ABSTRACTRuminant animals contribute significantly to methane emissions in tropical regions. Nonetheless, there are few facilities available in those regions of the world for in vivo measurement of methane production in cattle. The aim of the present work was to describe the design, construction and operation of respiration chambers for in vivo measurement of methane production in cattle in Mexico. Locally available materials were used in the construction. Walls, roof and doors were constructed of thermic panels with two windows of acrylic at the front so the animal can be observed at all times. Chambers have an air volume of 9.97 m3. Air is drawn from the chamber at a rate of 500 L/min by the effect of mass action flow generators. Methane was measured in air samples with an infrared analyzer. Chambers operate under a slight negative pressure of around -500 Pa. Air temperature inside the chambers is kept at 23 °C with an air conditioner, while relative humidity is maintained at 55 % with a dehumidifier. Functioning of the chambers was evaluated in Bos indicus, Nelore cattle fed Taiwan grass (Pennisetum purpureum) and a concentrate (18 % crude protein), and measurements were made during runs of 23 h duration. Methane production was on average 173.2 L per day, while the emission factor was 17.48 L methane per kilogram o dry matter consumed. It concludes that this respiration facility is capable of measuring methane production accurately in cattle fed tropical rations.

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