D. O’Callaghan

1.9k citations

52 papers · 1.6k · h-index 20

Impact in

Agronomy and Crop Science top 0.5%
- Reproductive Physiology in Livestock
- Ruminant Nutrition and Digestive Physiology
Reproductive Medicine top 2%
- Ovarian function and disorders
- Sperm and Testicular Function

Papers in

Agronomy and Crop Science 39
- Reproductive Physiology in Livestock 39
- Ruminant Nutrition and Digestive Physiology 12
Genetics 26
- Genetic and phenotypic traits in livestock 24

Co-authors: M.P. Boland (10 shared papers)P. Lonergan (6 shared papers)M.P. Boland (21 shared papers)J Roche (8 shared papers)S. Snijders (6 shared papers)P. Dillon (1 shared paper)H. Yaakub (4 shared papers)Fred J. Karsch (5 shared papers)
Journals: Theriogenology (12 papers)Reproduction (7 papers)Animal Science (5 papers)Biology of Reproduction (4 papers)Animal Reproduction Science (4 papers)
Partner nations: Ireland United States United Kingdom

In The Last Decade

D. O’Callaghan

51 papers receiving 1.4k citations

Peers

Replace R. P. Aitken with:

R. P. Aitken United Kingdom

A. S. McNeilly United Kingdom

N.C. Rawlings Canada

Flávia L. Lopes Brazil

G. Kann France

C. Viñoles Uruguay

J. Saumande France

A. Meikle Uruguay

A.P. Beard United Kingdom

I. Cumming Australia

D. O’Callaghan relative to R. P. Aitken United Kingdom R. P. Aitken's profile →

Citations per field

00.5×1.5×1.9×

R. P. Aitken · 1×

×1.4 1k/804

ACS

×1.4 230/163

RM

×1.6 718/461

GENET

×1.9 238/123

ASZ

×1.4 588/433

PHEOH

Citations per year

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Countries citing papers authored by D. O’Callaghan

Since Specialization

Citations

This map shows the geographic impact of D. O’Callaghan's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by D. O’Callaghan with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites D. O’Callaghan more than expected).

Fields of papers citing papers by D. O’Callaghan

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by D. O’Callaghan. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by D. O’Callaghan. The network helps show where D. O’Callaghan may publish in the future.

Co-authors

The 25 scholars most cited alongside D. O’Callaghan, linked wherever they have co-authored with each other. Click a name or a connecting line to browse the papers they share.

Border = papers with D. O’Callaghan Line = papers co-authored together D. O’Callaghan links everyone, so they are left out of the graph.

All Works

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20 of 20 papers shown

Showing the 20 most-cited of 52 papers — load more, or switch the sort, to bring in the rest.

#	Work
1	Effect of nutrition on endocrine parameters, ovarian physiology, and oocyte and embryo development Theriogenology ·M.P. Boland, P. Lonergan, D. O’Callaghan	2001	216
2	Nutritional effects on ovulation, embryo development and the establishment of pregnancy in ruminants Animal Science ·D. O’Callaghan, M.P. Boland	1999	139
3	Effect of genetic merit, milk yield, body condition and lactation number on in vitro oocyte development in dairy cows Theriogenology ·S. Snijders, P. Dillon, D. O’Callaghan, M.P. Boland	2000	137
4	Influence of nutrition on the effectiveness of superovulation programmes in ewes: effect on oocyte quality and post-fertilization development Reproduction ·JM Lozano, P. Lonergan, M.P. Boland, D. O’Callaghan	2003	92
5	Manipulation of Growth in Farm Animals J. F. Roche, D. O’Callaghan	1984	81
6	The influence of short-term nutrient changes on follicle growth and embryo production following superovulation in beef heifers Theriogenology ·Robert L. Nolan, D. O’Callaghan, R.T. Duby, P. Lonergan, M.P. Boland	1998	70
7	Effect of type and quantity of concentrates on superovulation and embryo yield in beef heifers Theriogenology ·H. Yaakub, D. O’Callaghan, M.P. Boland	1999	64
8	Follicular growth and ovulation rate in farm animals J Roche, D. O’Callaghan	1987	61
9	What Photoperiodic Signal is Provided by a Continuous-Release Melatonin Implant?1 Biology of Reproduction ·D. O’Callaghan, Fred J. Karsch, M.P. Boland, J. F. Roche	1991	59
10	Effect of diet quantity and urea supplementation on oocyte and embryo quality in sheep Theriogenology ·Serafeim Papadopoulos, P. Lonergan, Vivian Gath, K. Quinn, A.C.O. Evans, D. O’Callaghan, M.P. Boland	2001	55
11	Maternal Cigarette Smoking During Pregnancy Is an Independent Predictor for Symptoms of Middle Ear Disease at Five Years' Postdelivery PEDIATRICS ·Stephen L Stathis, D. O’Callaghan, Gail Williams, Jake M. Najman, Margaret J. Andersen, (unknown)	1999	53
12	Active immunization of heifers against a synthetic fragment of bovine inhibin Reproduction ·Adam Scanlon, S. Sunderland, Terry L. Martin, David Goulding, D. O’Callaghan, D.H. Williams, Denis R. Headon, M.P. Boland, James J. Ireland, J Roche	1993	46
13	Effects of superovulated heifer diet type and quantity on relative mRNA abundances and pyruvate metabolism in recovered embryos Reproduction ·C. Wrenzycki, Paul A. De Sousa, E.W. Overström, R.T. Duby, D. Herrmann, Andrew J. Watson, Heiner Niemann, D. O’Callaghan, M.P. Boland	2000	45
14	The effects of dietary urea on embryo development in superovulated donor ewes and on early embryo survival and development in recipient ewes Animal Science ·J. Fahey, M.P. Boland, D. O’Callaghan	2001	44
15	Changes induced in the bovine zona pellucida by ovine and bovine oviducts Theriogenology ·R.T. Duby, James L. Hill, D. O’Callaghan, E.W. Overström, M.P. Boland	1997	41
16	Effect of the presence of male and female flockmates on reproductive activity in ewes Reproduction ·D. O’Callaghan, A. Donovan, S. Sunderland, M.P. Boland, J Roche	1994	33
17	Effects of diet type on establishment of pregnancy and embryo development in beef heifers Theriogenology ·Vivian Gath, P. Lonergan, M.P. Boland, D. O’Callaghan	1999	32
18	Role of Short Days in Timing the Onset and Duration of Reproductive Activity in Ewes under Artificial Photoperiods1 Biology of Reproduction ·D. O’Callaghan, Fred J. Karsch, M.P. Boland, J. F. Roche	1991	26
19	Effect of immunization of rams against bovine inhibin α1–26 on semen characteristics, scrotal size, FSH, LH and testosterone concentrations Reproduction ·Raymond M. McKeown, D. O’Callaghan, J Roche, M.P. Boland	1997	22
20	Variation in the timing of the reproductive season among breeds of sheep in relation to differences in photoperiodic synchronization of an endogenous rhythm Reproduction ·D. O’Callaghan, Fred J. Karsch, M.P. Boland, J. P. Hanrahan, J. F. Roche	1992	19

About D. O’Callaghan

D. O’Callaghan is a scholar working on Agronomy and Crop Science, Genetics, Public Health, Environmental and Occupational Health, Animal Science and Zoology and Endocrine and Autonomic Systems, having authored 52 papers that have together received 1.6k indexed citations. Recurring topics across this work include Reproductive Physiology in Livestock (39 papers), Genetic and phenotypic traits in livestock (24 papers), Ruminant Nutrition and Digestive Physiology (12 papers), Reproductive Biology and Fertility (11 papers), Effects of Environmental Stressors on Livestock (6 papers), Circadian rhythm and melatonin (5 papers), Animal health and immunology (2 papers) and Animal Behavior and Welfare Studies (2 papers). The work is most often cited by research in Agronomy and Crop Science (1.1k citations), Reproductive Medicine (230 citations), Genetics (718 citations), Animal Science and Zoology (238 citations) and Public Health, Environmental and Occupational Health (588 citations). D. O’Callaghan has collaborated with scholars based in Ireland, United States and United Kingdom. Frequent co-authors include M.P. Boland, P. Lonergan, M.P. Boland, J Roche, S. Snijders, P. Dillon, H. Yaakub, Fred J. Karsch, J. F. Roche and R.T. Duby. Their work appears in journals such as Theriogenology, Reproduction, Animal Science, Biology of Reproduction and Animal Reproduction Science.

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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D. O’Callaghan

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