Exposure to androgenised steers did not improve the fertility obtained in progesterone-based fixed-timed artificial insemination programs in extensively managed cows and heifers

2010 ◽  
Vol 50 (1) ◽  
pp. 68 ◽  
Author(s):  
R. Ungerfeld
Keyword(s):  
Artificial Insemination ◽  
Present Experiment ◽  
Minimum Distance ◽  
Transrectal Ultrasound ◽  
Reproductive Activity ◽  
Early Summer ◽  
The Other ◽  
Previous Exposure ◽  
Timed Artificial Insemination ◽  
Stimulation Of

Biostimulation – the stimulation of females’ reproductive activity by the presence of males – has been used to stimulate postpartum rebreeding in cows, and to advance puberty in heifers. The objective of the present experiment was to determine whether previous exposure to androgenised steers improves conception rates after a progesterone-based fixed-timed artificial insemination program applied during spring. Three trials were carried out between October and January (spring–early summer) with a total of 903 Hereford and Hereford × Angus cows and heifers. All of the females were isolated from male contact (minimum distance = 4000 m) 3 months before the beginning of the experiments. While one group (EXP) in each trial was exposed to androgenised steers for 20 days, the other group (ISO) remained isolated from males (bulls, steers) during the experiment. In trial 1, 248 and 267 heifers were included in the EXP and ISO groups, respectively; in trial 2, 141 and 134 spring calving cows were used for the same treatments; and in trial 3, 53 and 60 autumn-calving cows were respectively included in the experimental groups. All animals were joined and a traditional progesterone-based fixed-timed artificial insemination program was applied to all of them. Pregnancy was determined 45–50 days after insemination with transrectal ultrasound. There were no differences between the EXP and ISO groups in any of the trials. The general conception rate was 54.6, 50.2 and 54.0% in trials 1, 2 and 3, respectively. Overall, it was concluded that exposition to androgenised steers does not improve the fertility obtained in progesterone-based fixed-timed artificial insemination programs in extensively managed cows and heifers.

scholarly journals Period of dominance of the ovulatory follicle influences embryo quality in lactating dairy cows

Reproduction ◽  
2009 ◽  
Vol 137 (5) ◽  
pp. 813-823 ◽  
Author(s):  
Ronaldo L A Cerri ◽  
Heloísa M Rutigliano ◽  
Ricardo C Chebel ◽  
José E P Santos
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Embryo Quality ◽  
Lower Proportion ◽  
Oestrous Cycle ◽  
The Other ◽  
Lactating Cows ◽  
Lactating Dairy Cows ◽  
Ovulatory Follicle ◽  
Timed Artificial Insemination

Length of dominance of the ovulatory follicle and exposure to oestradiol (OE2) during proestrus can affect fertility. Lactating cows had their oestrous cycle pre-synchronized and were subjected to one of the four synchronization treatments. Cows in the oestrus detection (OD) treatment received GnRH on day 6 of the oestrous cycle, PGF2α7 days later, and were inseminated at detected oestrus. The remaining cows were subjected to the Ovsynch (OVS) protocol (day 0 GnRH, day 7 PGF2α, day 9 GnRH, and timed artificial insemination (AI) 12 h later) starting on day 3 (OVS3) or day 6 (OVS6 and OVS6E) of the oestrous cycle. Cows in the OVS6E treatment received an injection of 0.5 mg oestradiol cypionate 36 h before AI. Ovaries were examined by ultrasonography and blood was sampled for progesterone and OE2concentrations. Uteri were flushed 6 days after AI and recovered embryos–oocytes evaluated. Diameter of the ovulatory follicle at AI differed (P<0.01) among treatments, and it was the largest for OVS3 cows, which also had extended (P<0.01) length of follicular dominance. During proestrus, OD and OVS6E cows had increased (P<0.01) OE2concentrations. Fertilization was not altered by treatments, and maximum fertilization was achieved when the number of accessory spermatozoa was >7. Proportions of viable embryos in relation to embryos and embryos–oocytes recovered were smaller for OVS3 cows (P<0.01) than the other treatments, and embryos from OVS3 cows also had fewer (P<0.01) blastomeres and tended (P=0.09) to have a lower proportion of live blastomeres. Extending the period of follicle dominance did not alter fertilization but reduced (P<0.001) embryo quality. Embryo quality was compromised even when the dominance of the ovulatory follicle was extended by only 1.5 days.

scholarly journals Artificial insemination system without estrous observation in suckled beef cows

2008 ◽  
Vol 39 (2) ◽  
pp. 496-501 ◽  
Author(s):  
Luiz Felipe Kruel Borges ◽  
Rogério Ferreira ◽  
Lucas Carvalho Siqueira ◽  
Rodrigo Camponogara Bohrer ◽  
Jacson William Borstmann ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Transrectal Ultrasound ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Timed Artificial Insemination ◽  
Average Size ◽  
Vaginal Device ◽  
Estrous Behavior ◽  
Follicular Dynamics

The aim was to develop a timed artificial insemination (TAI) system in suckled beef cows. Cows (n=227), 60-80 days postpartum, received estradiol benzoate (5mg) and a vaginal device containing 250µg of medroxyprogesterone acetate (MPA; day 0). On day six, cloprostenol (125µg) and eCG (400IU) were administrated and calves were weaned for 88h. The devices were removed on day seven (BioRep group) or on day eight (TAI group). All cows of TAI group and cows of BioRep group that did not exhibit standing estrus received GnRH (100µg) on day 9. In experiment I, the follicular growth was monitored daily by transrectal ultrasound exams, from day 6 to day 9. The average size of the dominant follicle on day nine was 11.1±0.99mm (BioRep, n=7) and 11.5±0.65mm (TAI, n=7) and all animals ovulated. In experiment II, the BioRep group cows (n=106) were observed for estrous behavior after withdrawal of the device, twice a day for 48h, and inseminated 12h after detection. In the TAI group (n=107), the devices were withdrawn on day eight and after 24h these cows and those from the BioRep group, which were not stand in estrus, received 100µg of GnRH and TAI 16h later. The pregnancy rates were 57.6% (BioRep) and 52.3% (TAI). In conclusion, an increase on MPA exposure time did not affect the follicular dynamics and pregnancy rates and allow TAI without estrous observation. Furthermore, the treatment for eight days provides an efficient TAI system in suckled beef cows.

scholarly journals Influence of Days after Calving and Thermal Stress on the Efficacy of a Progesterone-Based Treatment in Acyclic Italian Mediterranean Buffalo

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3166
Author(s):  
Roberta Matera ◽  
Alessio Cotticelli ◽  
Angela Salzano ◽  
Nadia Piscopo ◽  
Anna Balestrieri ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Odds Ratio ◽  
Body Condition Score ◽  
Class Ii ◽  
The Other ◽  
Class Iii ◽  
Condition Score ◽  
Pregnancy Status ◽  
Humidity Index ◽  
Timed Artificial Insemination

The aim of this study was to evaluate the efficacy of a progesterone-based treatment on anoestrus in buffaloes. Primiparous acyclic buffaloes (n = 276), were divided into three classes according to their days in milk (DIM): from 50 to 90 (Class I; n = 86), from 91 to 150 (Class II; n = 102) and from 150 to 200 (Class III; n = 88). Animals were synchronized using P4 vaginal implants, followed by timed artificial insemination (TAI). They were then allowed to enter into a larger group of buffaloes for natural mating 15 days after AI was performed, and pregnancy status was monitored from then on at 15-day intervals. Finally, the temperature–humidity index (THI) was calculated. Statistical analysis was performed by ANOVA by means and both multiple and linear regression. The total pregnancy rate (PR) was 87.7%, with no differences among DIM classes (88.0, 92.4, and 80.0% in Classes I, II, and III, respectively). However, the PR at TAI tended to be higher (p = 0.07) in buffaloes in Class II. The follicle (FL) area in Class II buffaloes was larger (p < 0.01) than that of the other classes. No influence of the THI on the total PR was recorded. The pregnancy outcome at TAI was affected by the FL area (odds ratio = 2.237; p < 0.05) and body condition score (BCS) (odds ratio = 1.256; p < 0.05). In conclusion, treatment with vaginal P4 optimizes pregnancy rates in anoestrus buffaloes, particularly when the animals are in mid-lactation and show an optimal BCS. Furthermore, the THI does not seem to affect the efficiency of the progesterone treatment.

Effect of treatment with melatonin implants in conjunction with teaser rams on the reproductive performances of Poll Dorset x Merino ewes joined in early summer in the south-west of Western Australia

1992 ◽  
Vol 32 (8) ◽  
pp. 1045 ◽  
Author(s):  
KP Croker ◽  
MA Johns ◽  
AH Williams ◽  
SR McPhee ◽  
LD Staples
Keyword(s):  
Reproductive Performance ◽  
Reproductive Activity ◽  
Early Summer ◽  
The Other ◽  
Control Group ◽  
Melatonin Treatment ◽  
South West ◽  
Effect Of Treatment ◽  
First Time ◽  
Teaser Rams

Melatonin pretreatment to improve the reproductive performance of first-cross Poll Dorset x Merino ewes joined in early summer was investigated in 2 experiments conducted in consecutive years. In experiment 1, melatonin pellets were administered subcutaneously to 1 of 3 groups of ewes; 14 days later they were joined with testosterone-primed wethers ('teasers'), followed after 15 days by entire rams (melatonin-teased group). The other groups were untreated and teased only. Experiment 2 consisted only of teased and melatonin-teased groups, with the ewes from experiment 1 being reallocated, as well as maiden ewes being joined for the first time. In this experiment melatonin pellets were inserted 38 days before the start of joining. Treatment with melatonin resulted in increased reproductive performances. The responses were characterised by an earlier (P<0.05) conception pattern in both experiments and higher (P<0.001) lambing percentages than controls in experiment 1. Up to 22% more lambs were born to melatonin-teased ewes than to teased ewes, and stimulatory effects were similar for ewes of different ages. In experiment 2, ewes that had received melatonin in both experiments tended (P>0.05) to have higher lambing percentages than teased ewes (up to 17% more lambs born), while ewes that had received melatonin in only experiment 1 tended (P>0.05) to have lower lambing percentages than ewes that were not treated with melatonin in either experiment (4-11%). The higher lambing performances of the melatonin-treated ewes were independent of ewe liveweights. Reproductive activity was also stimulated by the use of teasers alone in experiment 1. Conception patterns were advanced (P<0.01) and there was a trend for more (P>0.05) lambs to be born in the teased group than in the control group. The results show that both teasers and melatonin treatment will advance the conception patterns of first-cross Poll Dorset x Merino ewes joined in early summer, but the melatonin treatment also stimulated fecundity.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.

scholarly journals Receptor-operated Ca2+ channels in gastric parietal cells: gastrin and carbachol induce Ca2+ influx in depleting intracellular Ca2+ stores

1993 ◽  
Vol 289 (1) ◽  
pp. 117-124 ◽  
Author(s):  
S Roche ◽  
J P Bali ◽  
R Magous
Keyword(s):  
Steady State ◽  
Receptor Activation ◽  
Parietal Cells ◽  
The Other ◽  
Bivalent Cation ◽  
Gtp Binding ◽  
Gastric Parietal Cells ◽  
Type Receptor ◽  
Ca2 Channels ◽  
Stimulation Of

The mechanism whereby gastrin-type receptor and muscarinic M3-type receptor regulate free intracellular Ca2+ concentration ([Ca2+]i) was studied in rabbit gastric parietal cells stimulated by either gastrin or carbachol. Both agonists induced a biphasic [Ca2+]i response: a transient [Ca2+]i rise, followed by a sustained steady state depending on extracellular Ca2+. Gastrin and carbachol also caused a rapid and transient increase in Mn2+ influx (a tracer for bivalent-cation entry). Pre-stimulation of cells with one agonist drastically decreased both [Ca2+]i increase and Mn2+ influx induced by the other. Neither diltiazem nor pertussistoxin treatment had any effect on agonist-stimulated Mn2+ entry. Thapsigargin, a Ca(2+)-pump inhibitor, induced a biphasic [Ca2+]i increase, and enhanced the rate of Mn2+ entry. Preincubation of cells with thapsigargin inhibits the [Ca2+]i increase as well as Mn2+ entry stimulated by gastrin or by carbachol. Thapsigargin induced a weak but significant increase in Ins(1,4,5)P3 content, but this agent had no effect on the agonist-evoked Ins(1,4,5)P3 response. In permeabilized parietal cells, Ins(1,4,5)P3 and caffeine caused an immediate Ca2+ release from intracellular pools, followed by a reloading of Ca2+ pools which can be prevented in the presence of thapsigargin. We conclude that (i) gastrin and carbachol mobilize common Ca2+ intracellular stores, (ii) Ca2+ permeability secondary to receptor activation involves neither a voltage-sensitive Ca2+ channel nor a GTP-binding protein from the G1 family, and (iii) agonists regulate common Ca2+ channels in depleting intracellular Ca2+ stores.

LRH‐A3 and HCG increase pregnancy rate during timed artificial insemination in dairy cows

2021 ◽  
Vol 92 (1) ◽  
Author(s):  
Peng Zheng ◽  
He Huang ◽  
Xiaoyu Li ◽  
Fushuo Huang ◽  
Samson Olugbenga Adeniran ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Timed Artificial Insemination
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