J.J. Callan

J.J. Callan publication distribution in Animal Science and Veterinary in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Animal Science and Veterinary in 2026. The highlighted bar marks where J.J. Callan sits on this spectrum.

J.J. Callan D-index placement in Animal Science and Veterinary in 2026

The chart shows the D-index (discipline H-index) distribution of Animal Science and Veterinary scientists ranked by Research.com in 2026. The highlighted bar marks where J.J. Callan sits on this spectrum.

Overview

Best Publications

• Effect of forage/concentrate ratio and dietary coconut oil level on methane output and performance of finishing beef heifers

  D. Lovett;S. Lovell;L. Stack;J. Callan

  247
  Citations

• The effect of dietary Laminaria‐derived laminarin and fucoidan on nutrient digestibility, nitrogen utilisation, intestinal microflora and volatile fatty acid concentration in pigs

  Mary B Lynch;Torres Sweeney;James J Callan;John T O'Sullivan

  188
  Citations

• Effect of refined coconut oil or copra meal on methane output and on intake and performance of beef heifers.

  E. Jordan;D. K. Lovett;F. J. Monahan;J. Callan

  188
  Citations

• The effects of seaweed extract inclusion on gut morphology, selected intestinal microbiota, nutrient digestibility, volatile fatty acid concentrations and the immune status of the weaned pig.

  P. Reilly;J. V. O’Doherty;K. M. Pierce;J. J. Callan

  186
  Citations

• The effects of lactose inclusion and seaweed extract derived from Laminaria spp. on performance, digestibility of diet components and microbial populations in newly weaned pigs

  J.V. O’Doherty;S. Dillon;S. Figat;J.J. Callan

  147
  Citations

• Manipulating enteric methane emissions and animal performance of late-lactation dairy cows through concentrate supplementation at pasture.

  D.K. Lovett;L.J. Stack;S. Lovell;J. Callan

  142
  Citations

• Effect of DL-malic acid supplementation on feed intake, methane emission, and rumen fermentation in beef cattle

  P.A. Foley;D.A. Kenny;J.J. Callan;T.M. Boland

  130
  Citations

• A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions

  R.A. Palladino;F. Buckley;R. Prendiville;J.J. Murphy

  127
  Citations

• The effect of cereal type and exogenous enzyme supplementation in pig diets on nutrient digestibility, intestinal microflora, volatile fatty acid concentration and manure ammonia emissions from finisher pigs

  J.M. O'Connell;T. Sweeney;J. J. Callan;J. V. O'Doherty

  124
  Citations

• Supplementary concentrate type affects nitrogen excretion of grazing dairy cows.

  F.J. Mulligan;P. Dillon;J.J. Callan;M. Rath

  121
  Citations

• The effect of lactose and inulin on intestinal morphology, selected microbial populations and volatile fatty acid concentrations in the gastro-intestinal tract of the weanling pig

  K. M. Pierce;T. Sweeney;P. O. Brophy;J. J. Callan

  116
  Citations

• The effect of dietary garlic and rosemary on grower-finisher pig performance and sensory characteristics of pork

  S.P. Cullen;Frank J Monahan;J.J. Callan;John V. O'Doherty

  108
  Citations

• Performance of weanling piglets offered low-, medium- or high-lactose diets supplemented with a seaweed extract from Laminaria spp.

  D. A. Gahan;M. B. Lynch;J. J. Callan;J. T. O’Sullivan

  96
  Citations

• The effect of dietary crude protein level, cereal type and exogenous enzyme supplementation on nutrient digestibility, nitrogen excretion, faecal volatile fatty acid concentration and ammonia emissions from pigs

  J.M. O’Connell;J.J. Callan;J.V. O’Doherty

  90
  Citations

• The interaction between lactose level and crude protein concentration on piglet post-weaning performance, nitrogen metabolism, selected faecal microbial populations and faecal volatile fatty acid concentrations

  K.M. Pierce;J.J. Callan;P. McCarthy;J.V. O’Doherty

  88
  Citations

• The influence of manure composition on emissions of odour and ammonia from finishing pigs fed different concentrations of dietary crude protein

  Aidan B.G. Leek;Enda T. Hayes;Thomas P. Curran;James J. Callan

  87
  Citations

• Performance of weanling pigs offered low or high lactose diets supplemented with avilamycin or inulin

  K. M. Pierce;J. J. Callan;P. McCarthy;J. V. O'Doherty

  81
  Citations

• Effects of increasing the intake of dietary β-glucans by exchanging wheat for barley on nutrient digestibility, nitrogen excretion, intestinal microflora, volatile fatty acid concentration and manure ammonia emissions in finishing pigs

  M. B. Lynch;T. Sweeney;J. J. Callan;J. V. O’Doherty

  78
  Citations

• Effect of crude protein concentration and sugar-beet pulp on nutrient digestibility, nitrogen excretion, intestinal fermentation and manure ammonia and odour emissions from finisher pigs.

  M. B. Lynch;C. J. O’Shea;T. Sweeney;J. J. Callan

  76
  Citations

• The effect of varying levels of coconut oil on intake, digestibility and methane output from continental cross beef heifers

  E. Jordan;D. K. Lovett;M. Hawkins;J. J. Callan

  76
  Citations

• Effect of phytase inclusion and calcium/phosphorus ratio on the performance and nutrient retention of grower–finisher pigs fed barley/wheat/soya bean meal-based diets

  S M Brady;J J Callan;D Cowan;M McGrane

  69
  Citations

• Effect of β-glucans contained in barley- and oat-based diets and exogenous enzyme supplementation on gastrointestinal fermentation of finisher pigs and subsequent manure odor and ammonia emissions

  C. J. O’Shea;T. Sweeney;M. B. Lynch;D. A. Gahan

  65
  Citations

• The effect of inclusion of a high lactose supplement in finishing diets on nutrient digestibility, nitrogen excretion, volatile fatty acid concentrations and ammonia emission from boars

  K.M. Pierce;T. Sweeney;J.J. Callan;C. Byrne

  58
  Citations

• In vitro fermentation patterns and methane production as influenced by cultivar and season of harvest of Lolium perenne L.

  D. K. Lovett;D. McGilloway;A. Bortolozzo;M. Hawkins

  52
  Citations