Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows

Degaris, PJ; Lean, I.J.; Rabiee, A.R.; Heuer, C

doi:10.1111/j.1751-0813.2008.00335.x

Cited by 24 publications

(43 citation statements)

References 53 publications

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“…Bachman (2002) and Gulay et al (2003) have reported no loss with dry periods < 60 d. Sample sizes in both of those studies were small, however, and it has been shown (Kuhn & Hutchison, 2005) that even estimates in the wrong direction are not unlikely with such small sample sizes. On the other hand, an increase in yields of milk and protein and a decrease in milk fat content with an elongation of the dry period were recorded by Degaris et al (2008). Also consistent with us, Kuhn et al (2005aKuhn et al ( , 2007 cows.…”

Section: Discussionsupporting

confidence: 69%

Efecto de la duración del período seco en la posterior producción y reproducción en vacas Holstein

Hossein-Zadeh¹,

Mohit²

2013

Span. j. agric. res.

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Calving records of Holstein cows from January 1983 to December 2006 comprising 1,190 herds with 384,717 calving events were used to evaluate factors affecting the dry period length and effect of current dry days on the next productive and reproductive performances of Holstein cows. Statistical analyses of dry days, productive and reproductive traits in this study were performed as linear mixed models. Dry period length (DD) of cows was grouped into 14 classes from < 10 days through > 130 days. Average DD was 100.46 days in Holstein cows. Primiparous cows had the lowest DD and the mean of DD decreased over the years from 1983 to 2006 and summer calvers had the shortest DD (p < 0.001). Cows within the DD classes of 51-60 and 61-70 had the greatest actual milk yield, mature equivalent milk yield, adjusted milk yield, adjusted fat yield, mature equivalent milk yield, adjusted protein yield and mature equivalent protein yield (p < 0.05). Also, cows within the DD class of 0-10 had the greatest adjusted fat percentage, mature equivalent fat percentage and adjusted protein percentage (p < 0.05). Our current results showed a reduction in calving interval and age at calving after cows had shorter dry days than with other longer dry period lengths (p < 0.05). Given the recent advocacy for shortened dry periods, it is worthwhile to emphasize that 51 to 70 DD does provide maximal performance in Holstein cows.Additional key words: dairy cow; dry days; productive performance; reproductive performance.

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Section: Discussionsupporting

confidence: 69%

Efecto de la duración del período seco en la posterior producción y reproducción en vacas Holstein

Hossein-Zadeh¹,

Mohit²

2013

Span. j. agric. res.

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“…There are many examples of observational epidemiological study designs that provide useful evidence of disease or reproduction that include case-control studies (Davis et al, 1980), and cohort studies (Curtis et al,1984;Degaris et al, 2008). We recommend, in general, that the evidential base used in a meta-analysis consist of randomized controlled clinical studies or prospective cohort studies as these should provide the most rigorous data.…”

Section: Evidence In Animal Studiesmentioning

confidence: 99%

Invited review: Use of meta-analysis in animal health and reproduction: Methods and applications

Lean¹,

Rabiee

Duffield

et al. 2009

Journal of Dairy Science

198

173

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The objectives of this paper are to provide an introduction to meta-analysis and systematic review and to discuss the rationale for this type of research and other general considerations. We highlight methods used to produce a rigorous meta-analysis and discuss some aspects of interpretation of meta-analysis drawing on examples from the animal and veterinary science literature. Meta-analysis is a rapidly expanding area of research that has been relatively underutilized in animal and veterinary science. It is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing to the pooled analysis. The examination of variability or heterogeneity in study results is also a critical outcome. The benefits of meta-analysis include a consolidated and quantitative review of a large, and often complex, sometimes apparently conflicting, body of literature. Meta-analytic methods place less emphasis on dichotomous outcomes from null hypothesis significance testing and greater emphasis on determining the magnitude and the precision of an effect of interest. A substantial benefit of meta-analysis is the potential to investigate new hypotheses using existing data, both through the development of a priori hypotheses and by examination of the heterogeneity in study responses. The specification of the outcome and hypotheses that are tested is critical to the conduct of meta-analyses, as is a sensitive literature search. A failure to identify the majority of existing studies can lead to erroneous conclusions; however, there are methods of examining data to identify the potential for studies to be missing; for example, by the use of funnel plots. Many of the statistical methods to conduct meta-analysis are widely used. Bayesian methods are well suited to meta-analysis. The post-hoc methods used to evaluate heterogeneity and publication bias, which include the I 2 statistic, L'Abbé plots, Galbraith plots, Rosenthal's N, and influential study analysis are exclusively used in meta-analysis. Examples where meta-analyses have been repeated in animal science or veterinary medicine show good consistency in estimates of effect. Findings of studies to date have provided new understandings of rumen modifiers, milk fever, parasite control, mastitis, somatotropin, and reproductive manipulations. Rigorously conducted meta-analyses are useful tools to improve animal well-being and productivity. The need to integrate findings from many studies ensures that meta-analytic research is desirable and the large body of research now generated makes the conduct of this research feasible.

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“…Full details of sample size calculations, animals and management, experimental design and diets and data collection are provided elsewhere 15 …”

Section: Methodsmentioning

confidence: 99%

Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows

et al. 2010

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Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows

Abstract: Increasing exposure to prepartum transition diets increased milk and milk-protein yields and decreased the milk fat-percentage, but not the milk-protein percentage or milk-fat yield.

Cited by 24 publications

References 53 publications

Efecto de la duración del período seco en la posterior producción y reproducción en vacas Holstein

Efecto de la duración del período seco en la posterior producción y reproducción en vacas Holstein

Invited review: Use of meta-analysis in animal health and reproduction: Methods and applications

Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows

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