scholarly journals VARIATIONS IN AND RELATIONSHIPS BETWEEN REPRODUCTIVE PERFORMANCE AND GROWTH PARAMETERS IN YEARLING BEEF BULLS IN SINGLE-SIRE MATING AT PASTURE

1989 ◽  
Vol 69 (1) ◽  
pp. 39-46
Author(s):  
A. FARID ◽  
M. MAKARECHIAN ◽  
R. T. BERG ◽  
M. A. PRICE
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Pregnancy Rate ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Growth Parameters ◽  
Reproductive Traits ◽  
Phenotypic Variance ◽  
Breed Group ◽  
Beef Bulls

Yearling bull fertility, measured as pregnancy rate, percentage of calves born during the first 4 and 6 wk of calving and mean and median of calving date distribution, were studied in 109 single-sire breeding herds of two breed groups over a 10-yr period. The breed groups were Herefords bulls mated to purebred and crossbred Hereford cows, and Beef Synthetic bulls mated to Beef Synthetic cows. The bulls averaged 14 mo old at the start of breeding. The average bull-to-cow ratio was approximately 1:22, and the breeding season started on 1 July each year and extended for 60 d. Two out of 109 bulls (1.8%) were subfertile (less than 50% pregnancy of the herd). The Beef Synthetic, which had crossbred foundation, had significantly higher fertility, calved earlier, had smaller phenotypic variance, and lower year-to-year fluctuation in the reproductive traits than the Hereford. Variations in reproductive performances of bulls of the same breed group used in the same year were much larger than those among different years, the former comprised over 75% of phenotypic variance of the traits in the two breed groups. Relationships between fertility of bulls and their weight and growth parameters were negligible, but bull fertility tended (P < 0.10) to improve with age. Bulls that were heavy at weaning, end of feedlot test and breeding settled their mates earlier during the breeding season. Key words: Beef cattle, yearling bull, fertility

EFFECTS OF EXPOSURE TO BULLS AND BODY WEIGHT ON REPRODUCTIVE PERFORMANCE IN BEEF HEIFERS

1985 ◽  
Vol 65 (1) ◽  
pp. 31-36 ◽  
Author(s):  
M. MAKARECHIAN ◽  
A. FARID ◽  
R. T. BERG
Keyword(s):  
Body Weight ◽  
Pregnancy Rate ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Control Group ◽  
Group Effect ◽  
Beef Heifers ◽  
Heavy Body ◽  
Breed Group ◽  
Calving Season

Calving records of 174 2-yr-old heifers from four breed groups; Hereford (HE), Beef Synthetic (SY), Dairy Synthetic (SD) and Crossbred Hereford (HX) were used in this study. Half of the heifers were exposed to three epididymectomized bulls for 6 wk before the start of the breeding season. While exposure to bulls had little influence (P = 0.51) on pregnancy rate, it advanced the calving date by 5.5 days compared with the control group (P < 0.05). Calving season in the exposed heifers was 2 wk shorter than that in the control group. Effect of heifer body weight at the start of breeding season on pregnancy rate differed (P < 0.05) among the four breed groups. Low body weight at mating was associated with lowered fertility in SY, SD and HE while very heavy body weight resulted in lowered fertility in SY and SD breed groups. Increase in body weight advanced calving date in the HX breed group only. Key words: Beef cattle, heifer reproduction, bull exposure, body weight

Melengestrol acetate and estradiol-17β for synchronizing estrus and improving reproductive performance in beef cattle

1997 ◽  
Vol 77 (4) ◽  
pp. 683-688 ◽  
Author(s):  
J. P. Kastelic ◽  
D. H. McCartney ◽  
W. O. Olson ◽  
A. D. Barth ◽  
R. J. Mapletoft
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Pregnancy Rate ◽  
Reproductive Performance ◽  
Pregnancy Rates ◽  
Melengestrol Acetate ◽  
Estradiol 17Β

Four experiments were conducted to investigate the use of melengesterol acetate (MGA) and estradiol-17β (E-17β) for synchronizing estrus and improving reproductive performance in beef cattle. Synchronized pregnancy rates were higher (P < 0.05) in heifers fed MGA after AI than controls (4 of 9 versus 0 of 7, respectively), but were not different for cows (20 of 37, 54% versus 23 of 40, 58%). Estrus rate (percentage of cows detected in estrus) was higher (P < 0.05) for cows treated with E-17β + MGA compared with those treated with cloprostenol alone (85.0 versus 65.9%). Synchronized pregnancy rates were not significantly affected by feeding MGA or grain only after detected estrus and AI (20 of 31, 64% versus 17 of 30, 57%). For 20 cows not detected in estrus and bred 100 h after cloprostenol treatment, pregnancy rate was higher (P < 0.05) for those fed MGA after AI than controls (6 of 11, 54% versus 1 of 9, 11%). Feeding MGA after breeding may help to improve pregnancy rates. Key words: Melengesterol acetate, estradiol-17β, estrus, reproductive performance, beef cattle

scholarly journals Additive genetic, non-additive genetic and permanent environmental effects for female reproductive performance in seasonal calving dairy females

2016 ◽  
Vol 55 (1) ◽  
pp. 10-23 ◽  
Author(s):  
M.M. Kelleher ◽  
F. Buckley ◽  
R.D. Evans ◽  
D.P. Berry
Keyword(s):  
Pregnancy Rate ◽  
Breeding Season ◽  
Environmental Effects ◽  
Reproductive Performance ◽  
Mixed Models ◽  
Reproductive Traits ◽  
Calving Interval ◽  
Environmental Correlations ◽  
Percentage Unit ◽  
Calving Rate

AbstractExcellent reproductive performance (i.e. 365-day calving interval) is paramount to herd profit in seasonal-calving dairy systems. Reproductive targets are currently not being achieved in Irish dairy herds. Furthermore, most research on the genetics of reproductive performance in dairy cattle has focused primarily on lactating cows and relatively few studies have attempted to quantify the genetic contribution to differences in reproductive performance in nulliparae. The objective of the present study was to estimate the contribution of both the additive and non-additive genetic components, as well as the permanent environmental component, to phenotypic variation in the reproductive traits in nulliparous, primiparous and multiparous seasonal-calving dairy females. Reproductive phenotypes were available on up to 202,525 dairy females. Variance components were estimated using (repeatability where appropriate) linear animal mixed models; fixed effects included in the mixed models were contemporary group, parity (where appropriate), breed proportion, inter-breed specific heterosis coefficients and inter-breed specific recombination loss coefficients. Heritability of the reproductive traits ranged from 0.004 (pregnancy rate to first service) to 0.17 (age at first service in nulliparae), while repeatability estimates for the reproductive traits in cows ranged from 0.01 (calving interval) to 0.11 (pregnant in the first 42 days of the breeding season). Breed-specific heterosis regression coefficients suggest that, relative to the parental mean, a first-cross Holstein–Jersey crossbred was almost 7 days younger at first calving, had a 9-day shorter calving interval, a 6 percentage unit greater pregnancy rate in the first 42 days of the breeding season and a 3 percentage unit greater survival rate to next lactation. Heifer calving rate traits were strongly genetically correlated with age at first calving (–0.97 to –0.66) and calving rate in the first 42 days of the calving season for first parity cows (0.77 to 0.56), but genetic correlations with other cow reproductive traits were weak and inconsistent. Calving interval was strongly genetically correlated with the majority of the cow traits; 56%, 40%, and 92% of the genetic variation in calving interval was explained by calving to the first service interval, number of services and pregnant in the first 42 days of the breeding season, respectively. Permanent environmental correlations between the reproductive performance traits were generally moderate to strong. The existence of contributions from non-additive genetic and permanent environmental effects to phenotypic differences among cows suggests the usefulness of such information to rank cows on future expected performance; this was evidenced by a stronger correlation with future reproductive performance for an individual cow index that combined additive genetic, non-additive genetic and permanent environmental effects compared to an index based solely on additive genetic effects (i.e. estimated breeding values).

scholarly journals AVALIAÇÃO DO DESEMPENHO REPRODUTIVO DE VACAS NA REGIÃO DO PANTANAL SUL-MATO-GROSSENSE SUBMETIDAS A IATF Com Aplicação De GnRH

Nativa ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 281-285
Author(s):  
Gabriel Rodrigo Hass Perucchi ◽  
Gabriela de Souza Sartori ◽  
Richarlla Aparecida Buscariol Silva ◽  
Murilo da Silva Garcia ◽  
Rodrigo José Delgado Jardim ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Pregnancy Rate ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Body Condition Score ◽  
The Body ◽  
Mato Grosso ◽  
Condition Score ◽  
Timed Artificial Insemination ◽  
Mato Grosso Do Sul

A Inseminação artificial em tempo fixo (IATF) está se difundindo no Brasil, pois contribui para o aumento da produtividade. O objetivo neste trabalho foi avaliar o uso do GnRH em protocolos de IATF de vacas criadas no pantanal Sul-mato-grossense. Participaram da pesquisa 531 vacas paridas da raça Nelore, que foram avaliadas de acordo com o escore de condição corporal (ECC), submetidas a três tipos de protocolos de IATF (lote 1, 2 e 3). Após 40 dias da inseminação artificial foi realizado diagnóstico de gestação. As matrizes que não receberam GnRH no lote 1 (estro aparente), lote 2 (estro parcial) e lote 3 (sem apresentação de estro) apresentaram, respectivamente 55,4%, 19,2% e 25,9% de prenhez, enquanto as que receberam o fármaco apresentaram 48,6%, 37,2% e 38,8%. Relacionado ao ECC, pode-se observar que a maior taxa de prenhez ocorreu em animais com ECC 3. Primíparas apresentaram melhor taxa de prenhez quando receberam GnRH independente do ECC. Concluiu-se que o uso de GnRH mostrou-se eficiente para melhoria da taxa de prenhez principalmente em primíparas, assim como nos animais que não apresentaram estro ou apresentaram estro parcial, e que matrizes com ECC 3 apresentaram melhores taxas de prenhez que vacas com escore inferior. Palavras-chave: bovino de corte; inseminação artificial em tempo fixo; produtividade; GnRH; Nelore.   Evaluation of cow reproductive performance in the region of Mato Grosso do Sul swamp submitted to TAI with GnRH application   ABSTRACT: The technique of timed artificial insemination (TAI) is spreading in Brazil, as it contributes to the increase of productivity. The objective of this work was to evaluate the use of GnRH in TAI protocols of cows raised in the swamp of Mato Grosso do Sul. 531 Nelore breed calved cows participate in the survey, which were evaluated according to the body condition score (BCS), and then performed three types of TAI protocols (batch 1, 2 and 3). After 40 days of the insemination, a pregnancy diagnosis was made. The matrices that did not receive GnRH in batch 1 (apparent oestrus), batch 2 (partial oestrus) and batch 3 (no oestrus presentation) presented respectively 55.4%, 19.2% and 25.9% of pregnancy, while those receiving the drug showed 48.6%, 37.2% and 38.8%. Related to BCS, it can be observed that the highest pregnancy rate occurred in animals with BCS 3. Primiparous had a better pregnancy rate when receiving GnRH regardless of BCS. It was concluded that the use of GnRH was efficient to improve the pregnancy rate mainly in primiparous as well as animals that showed no oestrus or partial oestrus, and matrices with BCS 3 had better pregnancy rates than cows with lower scores. Keywords: beef cattle; timed artificial insemination; productivity; GnRH; Nelore.

The influence of purified porcine relaxin on the reproductive performance of sows following artificial insemination with fresh or frozen semen

1991 ◽  
Vol 71 (1) ◽  
pp. 237-239 ◽  
Author(s):  
P. A. Thacker ◽  
A. D. Gooneratne ◽  
R. N. Kirkwood
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Frozen Semen

Pregnancy rates and litter sizes following insemination of sows with fresh-extended and frozen-thawed semen averaged 71 vs. 53% and 10.6 vs. 4.4, respectively, and was not affected by the addition of 12.5 μg relaxin to semen. These results indicate no relaxin mediated effect on either pregnancy rate or litter size when sows are artificially inseminated with relaxin-supplemented semen. Key words: Artificial insemination, relaxin, sows

Using blup to estimate responses est a sheep flock selected for litter size

1993 ◽  
Vol 1993 ◽  
pp. 105-105
Author(s):  
G.E. Pollott
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Phenotypic Variance ◽  
Sheep Flock ◽  
Sheep Population ◽  
Important Contributor ◽  
Selection Experiments ◽  
Genetic Trends

The reproductive performance of ewes is an important contributor to flock profitability in many different situations. Although the heritability of reproductive traits is low there is often enough phenotypic variance to make a consideration of selection a possibility for improvement in litter size. Genetic trends in selection experiments have traditionally been monitored using a control flock which should be kept as an unseletced group. The recent availability of user friedly BLUP programs have added an extra method for estimating genetic trends. This paper reports the use of BLUP to estimate the genetic trends in a sheep population selected for litter size.

Machine effects on accuracy of ultrasonic prediction of backfat and ribeye area in beef bulls, steers and heifers

2000 ◽  
Vol 80 (1) ◽  
pp. 19-24 ◽  
Author(s):  
P. K. Charagu ◽  
D. H. Crews Jr. ◽  
R. A. Kemp ◽  
P. B. Mwansa
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Standard Error ◽  
Important Relationship ◽  
Ribeye Area ◽  
Beef Bulls ◽  
The Difference

Pre-slaughter ultrasound and carcass measurements of ribeye area (REA) and backfat (FAT) were recorded on composite beef bulls (n = 60), heifers (n = 60) and steers (n = 60). Breed composition of the composite was: 0.44 British (Hereford, Angus and Shorthorn) 0.25 Charolais, 0.25 Simmental and 0.06 Limousin. The Aloka SSD-1100 (AL) and the Tokyo Keiki CS 3000 (TK) ultrasound machines were compared by evaluating the difference between ultrasound and carcass measurements (bias), and the standard error of prediction (SEP). AL under-predicted REA in all three sexes while TK overpredicted heifers and steers and underpredicted bulls. Both machines were similar in accuracy among bulls for REA. For FAT AL underpredicted all three sexes while TK underpredicted heifers and had very small bias for bulls and steers. SEP for FAT were similar for both machines. Both machines underpredicted REA in larger muscled cattle and overpredicted in smaller-muscled cattle. Both machines also underpredicted FAT in fatter animals and overpredicted FAT in leaner animals. Machines were similar in accuracy among cattle with larger REA but differed significantly (P < 0.05) among smaller-muscled cattle. Machines were comparable in accuracy among animals of all FAT sizes. This study demonstrates that there is an important relationship between machine and the size and depth of muscle and backfat, respectively, and consequently between machine and sex, in accuracy of ultrasound prediction. Key words: Beef cattle, ultrasound, accuracy, back fat, ribeye area

Selection for cow lifetime pregnancy rate using bull and heifer growth and reproductive traits in composite cattle

2000 ◽  
Vol 80 (3) ◽  
pp. 507-510 ◽  
Author(s):  
P. B. Mwansa ◽  
R. A. Kemp ◽  
D. H. Crews Jr ◽  
J. P. Kastelic ◽  
D. R. C. Bailey ◽  
...  
Keyword(s):  
Birth Weight ◽  
Key Words ◽  
Pregnancy Rate ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Genetic Change ◽  
Direct Selection ◽  
Scrotal Circumference ◽  
Selection For

Genetic correlations of lifetime pregnancy rate with bull and heifer growth and reproductive traits in a beef composite population were estimated. Yearling scrotal circumference had an unfavorable genetic correlation (rg = −0.25) while yearling tonometer score was favorably related (rg = 0.22) to lifetime pregnancy rate. Heifer pregnancy rate, birth weight, weaning weight, yearling weight and age at puberty in heifers had significant genetic correlations (rg = 0.97, 0.58, 0.57, 0.33 and −0.21, respectively) with lifetime pregnancy rate. Lifetime pregnancy rate may be successfully predicted by easy-to-measure heifer growth traits. Using indices including scrotal and heifer growth traits, annual genetic change in lifetime pregnancy rate may be increased 3.1 times compared with direct selection. Key words: Scrotal circumference, tonometer, pregnancy, reproduction, puberty

scholarly journals Genetic and Genomic Analyses of Service Sire Effect on Female Reproductive Traits in Holstein Cattle

2021 ◽  
Vol 12 ◽  
Author(s):  
Ziwei Chen ◽  
Luiz F. Brito ◽  
Hanpeng Luo ◽  
Rui Shi ◽  
Yao Chang ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Genetic Effects ◽  
Holstein Cattle ◽  
Phenotypic Variance ◽  
Breeding Values ◽  
Female Reproductive Traits ◽  
Success Traits ◽  
Calving Traits

Fertility and reproductive performance are key drivers of dairy farm profitability. Hence, reproduction traits have been included in a large majority of worldwide dairy cattle selection indexes. The reproductive traits are lowly heritable but can be improved through direct genetic selection. However, most scientific studies and dairy cattle breeding programs have focused solely on the genetic effects of the dam (GED) on reproductive performance and, therefore, ignored the contribution of the service sire in the phenotypic outcomes. This study aimed to investigate the service sire effects on female reproductive traits in Holstein cattle from a genomic perspective. Genetic parameter estimation and genome-wide association studies (GWAS) were performed for the genetic effect of service sire (GESS) on conception rate (CR), 56-day non-return rate (NRR56), calving ease (CE), stillbirth (SB), and gestation length (GL). Our findings indicate that the additive genetic effects of both sire and dam contribute to the phenotypic variance of reproductive traits measured in females (0.0196 vs. 0.0109, 0.0237 vs. 0.0133, 0.0040 vs. 0.0289, 0.0782 vs. 0.0083, and 0.1024 vs. 0.1020 for GESS and GED heritability estimates for CR, NRR56, CE, SB, and GL, respectively), and these two genetic effects are positively correlated for SB (0.1394) and GL (0.7871). Interestingly, the breeding values for GESS on insemination success traits (CR and NRR56) are unfavorably and significantly correlated with some production, health, and type breeding values (ranging from −0.449 to 0.274), while the GESS values on calving traits (CE, SB, and GL) are usually favorably associated with those traits (ranging from −0.493 to 0.313). One hundred sixty-two significant single-nucleotide polymorphisms (SNPs) and their surrounding protein-coding genes were identified as significantly associated with GESS and GED, respectively. Six genes overlapped between GESS and GED for calving traits and 10 genes overlapped between GESS for success traits and calving traits. Our findings indicate the importance of considering the GESS when genetically evaluating the female reproductive traits in Holstein cattle.

INFLUENCE OF BREED ON THE REPRODUCTIVE PERFORMANCE OF EWES TREATED WITH FLUOROGESTONE-ACETATE-IMPREGNATED INTRAVAGINAL SPONGE AND PREGNANT MARE'S SERUM GONADOTROPHIN DURING THE BREEDING SEASON

1983 ◽  
Vol 63 (1) ◽  
pp. 1-6
Author(s):  
J. N. B. SHRESTHA ◽  
L. AINSWORTH ◽  
D. P. HEANEY
Keyword(s):  
Key Words ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Field Conditions ◽  
Reproductive Outcome ◽  
The North ◽  
Single Location ◽  
Significant Difference

The influence of breed on the reproductive performance of 454 mature ewes treated with fluorogestone acetate (FGA)-impregnated intravaginal sponges and pregnant mare's serum gonadotrophin (PMSG) to induce synchronized estrus during the breeding season was studied from 1978 to 1980 at a single location under field conditions. Fertility and fecundity after breeding at the synchronized estrus were, respectively, 79 and 145% for Polled Dorset, 51 and 94% for Suffolk, and 65 and 113% for North Country Cheviot breeds. The fertility and fecundity of the Polled Dorset were significantly higher than those of the Suffolk, but the North Country Cheviot was not significantly different from Polled Dorset and Suffolk breeds. There was no significant difference among the breeds with respect to prolificacy. Significant year-to-year variation in fertility and fecundity, but not in prolificacy, was observed among breeds with respect to FGA-PMSG treatment at the synchronized estrus. We conclude that the use of FGA-impregnated intravaginal sponge and PMSG treatment with appropriate breeds of sheep may further enhance the reproductive outcome of breeding at the synchronized estrus during the breeding season. Key words: Breeds, sheep, FGA sponge, PMSG, reproduction

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