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Camden, Australia
Camden, Australia

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Lean I.J.,SBScibus | Thompson J.M.,University of New England of Australia | Dunshea F.R.,University of Melbourne
PLoS ONE | Year: 2014

This study is a meta-analysis of the effects of the beta-agonists zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RAC) on feedlot performance, carcase characteristics of cattle and Warner Bratzler shear force (WBSF) of muscles. It was conducted to evaluate the effect of the use of these agents on beef production and meat quality and to provide data that would be useful in considerations on the effect of these agents on meat quality in Meat Standards Australia evaluations. We conducted a comprehensive literature search and study assessment using PubMed, Google Scholar, ScienceDirect, Scirus, and CAB and identification of other studies from reference lists in papers and searches. Searches were based on the key words: zilpaterol, zilmax, ractopamine, optaflexx, cattle and beef. Studies from theses obtained were included. Data were extracted from more than 50 comparisons for both agents and analysed using meta-analysis and meta-regression. Both agents markedly increased weight gain, hot carcase weight and longissimus muscle area and increased the efficiency of gain:feed. These effects were particularly large for ZH, however, fat thickness was decreased by ZH, but not RAC. Zilpaterol also markedly increased WBSF by 1.2 standard deviations and more than 0.8 kg, while RAC increased WBSF by 0.43 standard deviations and 0.2 kg. There is evidence in the ZH studies, in particular, of profound re-partitioning of nutrients from fat to protein depots. This work has provided critically needed information on the effects of ZH and RAC on production, efficiency and meat quality. © 2014 Lean et al.


Bramley E.,Murdoch University | Lean I.J.,SBScibus | Fulkerson W.J.,Dairy Farm Consulting | Costa N.D.,Murdoch University
Animal Production Science | Year: 2012

Feeding practices in Australian dairy herds were recorded in 100 dairy herds in five districts of two states. A questionnaire about the feeding practices was completed and pasture samples were also collected, where applicable, for analysis. Data and pasture samples were collected once from each farm with visits to regions occurring at different times of the year. Diets were evaluated for nutritional adequacy using the CPM Dairy program. Average milk yield on the day of sampling was 22.8 L/day. The combination of grazed pasture with grain fed during milking was the most prevalent feeding system (54%) in all areas. This was followed by combination of pelleted grain/by-products combined with pasture grazing (25%). Only one herd in the study was not feeding any form of concentrates at the time of sampling. The estimated percentage of concentrate in the diet ranged from 25% ± 11.6 to 44% ± 12.0. Wheat, which was fed at up to 9.8 kg/cow.day DM was the most prevalent grain in all areas, except for Gippsland. The predominant sources of protein in all areas were canola meal, cottonseed meal and lupins. By-products were prevalent, with brewers grain and wheat millrun the most commonly used, fed at 2.8 and 1.6 kg/cow.day DM, respectively. Most farms (81/100) incorporated at least one type of 'buffer' in the ration, and limestone (67%) was the most prevalent mineral additive. Monensin and virginiamycin were fed in all areas, with a varying prevalence. Feeding or dose rates used for minerals and rumen modifiers were not always appropriate to those recommended for mineral needs or control of rumen function. This paper demonstrated that a wide variety of feeding systems are used in Australian dairy herds and provides information on nutritive characteristics of pastures. © 2012 CSIRO.


Rabiee A.R.,SBScibus | Lean I.J.,SBScibus | Stevenson M.A.,Massey University | Socha M.T.,Zinpro Corporation
Journal of Dairy Science | Year: 2010

The objectives of this meta-analysis were to evaluate the effectiveness of supplementation with the organic trace minerals (OTM; Availa-4 and 4-Plex, Zinpro Corp., Eden Prairie, MN) on milk yield, composition, and component yields and reproductive performance in dairy cows. Twenty research papers and reports on the effects of OTM were considered in this meta-analysis. Criteria for inclusion in the study were information on the form of OTM, an adequate description of randomization, production and reproduction data, and associated measures of variance (SE or SD) and P-values. The OTM increased milk production by 0.93. kg [95% confidence interval (CI) = 0.61 to 1.25], milk fat by 0.04. kg (95% CI = 0.02 to 0.05), and milk protein by 0.03. kg (95% CI = 0.02 to 0.04) per day. Milk SCC was not different in cows supplemented with OTM. All production outcomes except milk solids (yield) and milk SCC were heterogeneous. Meta-regression analysis showed that feeding before calving, feeding for a full lactation after calving, and the use of other supplements increased responses over feeding after calving only, feeding for part of lactation, or not using other supplements, respectively. Supplementation of cows with OTM reduced days open (weighted mean difference = 13.5 d) and number of services per conception (weighted mean difference = 0.27) in lactating dairy cows. The risk of pregnancy on d 150 of lactation was greater in cows fed OTM (risk ratio = 1.07), but OTM had no significant effect on the interval from calving to first service and 21-d pregnancy rate. There was no evidence of heterogeneity for any of the reproductive outcomes evaluated. The results of this meta-analysis showed that organic trace mineral supplementation could improve production and reproduction in lactating dairy cows. © 2010 American Dairy Science Association.


Poppy G.D.,Colorado State University | Rabiee A.R.,SBScibus | Lean I.J.,SBScibus | Sanchez W.K.,Diamond V | And 2 more authors.
Journal of Dairy Science | Year: 2012

The purpose of this study was to use meta-analytic methods to estimate the effect of a commercially available yeast culture product on milk production and other production measures in lactating dairy cows using a meta-analysis of randomized controlled trials. Sixty-one research publications (published journal articles, published abstracts, and technical reports) were identified through a review of literature provided by the manufacturer and a search of published literature using 6 search engines. Thirty-six separate studies with 69 comparisons met the criteria for inclusion in the meta-analysis. The fixed-effect meta-analysis showed substantial heterogeneity for milk yield, energy-corrected milk, 3.5% fat-corrected milk, milk fat yield, and milk protein yield. Sub-group analysis of the data showed much less heterogeneity in peer-reviewed studies versus non-peer-reviewed abstracts and technical reports, and tended to show higher, but not significantly different, treatment effects. A random-effects meta-analysis showed estimated raw mean differences between treated and untreated cattle reported in peer-reviewed publications of 1.18. kg/d [95% confidence interval (CI): 0.55 to 1.81], 1.61. kg/d (95% CI: 0.92 to 2.29), and 1.65. kg/d (95% CI: 0.97 to 2.34) for milk yield, 3.5% fat-corrected milk, and energy-corrected milk, respectively. Milk fat yield and milk protein yield for peer-reviewed studies showed an increase in the raw mean difference of 0.06. kg/d (95% CI: 0.01 to 0.10) and 0.03. kg/d (95% CI: 0.00 to 0.05), respectively. Estimated raw mean dry matter intake of the peer-reviewed studies during early lactation (<70 d in milk) and not-early lactation were 0.62. kg/d (95% CI: 0.21 to 1.02) and a decrease of 0.78. kg/d (95% CI: -1.36 to -0.21), respectively. These findings provide strong evidence that this commercially available yeast culture product provides significant improvement in several important milk production outcomes as evaluated in production settings typical for commercial dairies in North America. Utilizing meta-analytic methods to study the complete breadth of information relating to a specific treatment by studying multiple overcomes of all eligible studies can reduce the uncertainty often seen in small individual studies designed without sufficient power to detect differences in treatments. © 2012 American Dairy Science Association.


Bisinotto R.S.,University of Florida | Lean I.J.,SBScibus | Thatcher W.W.,University of Florida | Santos J.E.P.,University of Florida
Journal of Dairy Science | Year: 2015

A systematic review of the literature was performed with the objective to evaluate the effects of progesterone supplementation using a single intravaginal insert during timed artificial insemination (AI) programs on fertility in lactating dairy cows. A total of 25 randomized controlled studies including 8,285 supplemented cows and 8,398 untreated controls were included in the meta-analysis. Information regarding the presence of corpus luteum (CL) at the initiation of the synchronization protocol was available for 6,883 supplemented cows and 6,879 untreated controls in 21 experiments. Studies were classified based on service number (first AI vs. resynchronized AI), use of presynchronization (yes vs. no), and insemination of cows in estrus during the synchronization protocol (inseminated in estrus and timed AI vs. timed AI only). Reproductive outcomes of interest were pregnancy per AI (P/AI) measured on d 32 (27 to 42) and 60 (41 to 71) after AI, and pregnancy loss between d 32 and 60 of gestation. Random effects meta-analyses were conducted and treatment effect was summarized into a pooled risk ratio with the Knapp-Hartung modification (RRK+H). The effect of moderator variables was assessed using meta-regression analyses. Progesterone supplementation increased the risk of pregnancy on d 32 [RRK+H=1.08; 95% confidence interval (CI)=1.02-1.14] and 60 after AI (RRK+H=1.10; 95% CI=1.03-1.17). The benefit of progesterone supplementation was observed mainly in cows lacking a CL at the initiation of the timed AI program (d 60: RRK+H=1.18; 95% CI=1.07-1.30) rather than those with CL (d 60: RRK+H=1.06; 95% CI=0.99-1.12). Progesterone supplementation benefited P/AI in studies in which all cows were inseminated at timed AI (d 60: RRK+H=1.20; 95% CI=1.10-1.29), but not in studies in which cows could be inseminated in estrus during the timed AI program (d 60: RRK+H=1.04; 95% CI=0.92-1.16). Progesterone supplementation tended to reduce the risk of pregnancy loss (RRK+H=0.84; 95% CI=0.67-1.00). Service number and presynchronization did not influence the effect of progesterone supplementation on fertility. In summary, progesterone supplementation using a single intravaginal insert during the timed AI program increased P/AI mostly in cows without CL and reduced the risk of pregnancy loss in lactating dairy cows. Insemination of cows in estrus during the synchronization protocol eliminated the benefit of supplemental progesterone on P/AI. © 2015 American Dairy Science Association.


Lean I.J.,SBScibus | Lean I.J.,University of Sydney | Golder H.M.,SBScibus | Golder H.M.,University of Sydney | Hall M.B.,U.S. Department of Agriculture
Veterinary Clinics of North America - Food Animal Practice | Year: 2014

Achieving optimal rumen function requires an understanding of feeds and systems of nutritional evaluation. Key influences on optimal function include achieving good dry matter intake. The function of feeds in the rumen depends on other factors including chemical composition, rate of passage, degradation rate of the feed, availability of other substrates and cofactors, and individual animal variation. This article discusses carbohydrate, protein, and fat metabolism in the rumen, and provides practical means of evaluation of rations in the field. Conditions under which rumen function is suboptimal (ie, acidosis and bloat) are discussed, and methods for control examined. © 2014 Elsevier Inc.


Lean I.J.,SBScibus | Van Saun R.,Pennsylvania State University | DeGaris P.J.,Tarwin Veterinary Group
Veterinary Clinics of North America - Food Animal Practice | Year: 2013

The aims of this article are to briefly review some of the underlying physiology of changes that occur around calving, examine the potential to control the risk of disease in this period, increase milk production, and improve reproductive performance through better nutritional management. Practical guidelines for veterinarians and advisors are provided. © 2013 Elsevier Inc.


Lean I.J.,SBScibus | Saun R.V.,Pennsylvania State University | DeGaris P.J.,Tarwin Veterinary Group
Veterinary Clinics of North America - Food Animal Practice | Year: 2013

Transition management needs to be fully integrated to be effective. We discuss and demonstrate this concept in the context of a study that used these principles. The roles of calcium, magnesium, phosphorus and dietary anion cation difference in influencing the pathophysiology and incidence of hypocalcemia are highlighted. Recent understandings of the pivotal role of skeleton in metabolism are reviewed. Micronutrient mineral and vitamin needs are addressed in the context of exposure of periparturient cattle to oxidative stress and inflammatory disorders. This article provides a series of practical approaches to improving transition diets. © 2013 Elsevier Inc.


Lean I.J.,SBScibus
Animal Production Science | Year: 2013

Considerable progress has been made in reducing starvation during the past century. This was achieved through increased use of arable land and adoption of new technologies. Future increases in food production will depend to a greater extent than in the past on the adoption of new technologies and must be even more rapidly achieved than in the past to meet the increase in demand for food. Intensive industries such as the poultry industry are under pressure from those engaged with a naturalistic fallacy. Technologies such as antibiotics for chickens or hormonal growth promotants (HGPs) for beef cattle that are safe for people, reduce environmental impacts of production, increase profits for producers, and improve animal well-being will be needed to achieve these increases in food production. The precedent set in the EU in banning HGPs can be understood as a response to the illegal abuse of diethylstilboestrol in the EU and as a non-tariff trade barrier to reduce the importation of beef from more efficient producers. The banning of antibiotics in the EU reflects the unwise application of a 'precautionary principle' through which risks were not soundly assessed. However, the unilateral ban established by Coles Supermarkets Pty Ltd on HGPs in Australia represents a more dangerous development, in which marketing ploys have been accorded a higher value than the care of animals, the environment, or the profit made by producers. Decisions such as these have reduced the viability of animal production in the UK and pose a threat to sustainable agricultural production in Australia. © CSIRO 2013.


Lean I.J.,SBScibus | Westwood C.T.,PGG Wrightson Seeds Ltd. | Golder H.M.,SBScibus | Vermunt J.J.,James Cook University
Livestock Science | Year: 2013

This review has a focus on understandings of horn structure, the digital fat pad and associations between ruminal acidosis and lameness. While there is an abundance of basic studies, particularly those examining putative mechanisms influencing risk of lameness and observational field studies, there are relatively few randomised controlled intervention studies. Consequently, the strength of the evidence for some interventions is not high. While there is evidence that increased grain feeding and increased ratios of non-fibre carbohydrates to neutral detergent fibre are associated with increased lameness, evidence for starch effects, per se, on laminitis is limited. There is strong evidence that fructans and glucose increase lactic acid production and laminitis. There is a need for more studies on the role of protein and risk of lameness. Histamine, endotoxin and lactic acid are either present in feed or generated in the rumen; can be absorbed; and have caused laminitis when injected. These provide potential links between ruminal acidosis and laminitis, but may not be the sole agents involved, and there are risks that these agents and other vasoactive agents pose that may be influenced by gut lesions. The important role of lipids in hoof wall integrity and in the digital hoof pad support understandings that trace elements and vitamins involved in pathways that control and limit oxidative damage may be important to hoof health. Further, associations between digital fat pad depth and body condition score suggest that dietary precursors for fats including preformed lipids in the diet and those derived from short chained fats may influence lameness.There is evidence that biotin reduces the risk of lameness, but there is a need for more consistent studies to identify which forms of lameness are reduced. Monensin and organic trace element complexes have reduced lameness in some studies, but the results are not consistently significant and more studies are needed to evaluate responses, especially effects on specific hoof conditions.The well-established effects of mineral nutrition on bone health were briefly examined, as were the effects of toxins. There is considerable scope for well-designed studies to evaluate the complex interactions among nutrients and the various forms of lameness. © 2013 Elsevier B.V.

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