Effects of season and age at first calving on genetic and phenotypic characteristics of lactation curve parameters in Holstein cows

Torshizi, Mahdi Elahi

doi:10.1186/s40781-016-0089-1

Cited by 30 publications

(29 citation statements)

References 37 publications

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“…In the same line with the current study, Torshizi [ 25 ] reported that both the feeding schedule and the relative humidity are the critical factors for calving season definition; hot weather seasons have a passive effect on milk characteristics, especially fat yield. As proposed by this author, cows that calved in autumn and winter seasons have average peak milk production more than ones calved in spring and summer seasons.…”

Section: Discussionsupporting

confidence: 88%

Classification and prediction of milk yield level for Holstein Friesian cattle using parametric and non-parametric statistical classification models

2020

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Objective: The objective of this study was to assess the veracities of most admired strategy discriminant analysis (DA), in comparison to the artificial neural network (ANN) for the anticipation and classification of milk production level in Holstein Friesian cattle using their performances. Materials and Methods: A total of 3,460 performance records of imported and locally born Holstein Friesian cows were gathered during the period from 2000 to 2016 to compare two alternative techniques for predicting the level of production based on performance traits in dairy cattle with the use of statistical software (Statistical Package for the Social Sciences, version 20.0). Results: The findings of the comparison indicated that ANN was more impressive in the expectancy of milk production level than did an imitator statistical method based on DA. The accuracy of the ANN model was high for the winter season (79.5%), whereas it was 47.3% for DA. The current findings were assured via the areas under receiver operating characteristic curves (AUROC) for DA and ANN. AUROC curves were smaller in the condition of the DA model across different calving seasons compared with the ANN model. The inaccuracies of variations were significant at a 5% significance level utilizing paired sample t -test. Conclusion: ANN model can be used efficiently to predict the level of production across the different calving seasons compared to the DA model.

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Section: Discussionsupporting

confidence: 88%

Classification and prediction of milk yield level for Holstein Friesian cattle using parametric and non-parametric statistical classification models

2020

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“…The heritability for AFC in this study was close to zero (0.00 ± 0.05). Torshizi (2016) reported a low h 2 value (0.075 ± 0.002) in Iranian Holstein cows. This result differs from what has been previously reported in BON cattle in a study carried out by M-Rocha et al (2012).…”

Section: Results and Discusionmentioning

confidence: 90%

Genetic parameters and trends for reproductive traits in Blanco Orejinegro cattle from Colombia

Caivio-Nasner

Herrera

et al. 2021

Semina: Ciênc. Agrár.

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The Colombian creole cattle breed Blanco Orejinegro (BON) is an important zoogenetic resource, but there is little knowledge about the genetic parameters and trends of its reproductive traits. Therefore, the aim of this study was to estimate parameters for the reproductive traits calving interval (CI), age at first calving (AFC), gestation duration (GD) and genetic trends for CI in the BON breed. Genealogy information from 7,799 animals was used, and employing the MTDFREML program, the components of the variance, heritability (h2), repeatability (rep), and estimated breeding values (EBV) for CI (n=3308), AFC (n=729), and GD (n=306) were estimated, in addition to the inbreeding coefficient (F) of the population. Genetic trends were established through linear regression using R software. Finally, the animals were classified as inbred (F > 0) and noninbred (F=0), and the effect of inbreeding on reproductive performance was established through a generalized linear model using the R program. An average F value of 4.41%±0.06 was observed. The h2 for CI was 0.11±0.03 with a rep of 0.15±0.04; for AFC, h2 was 0.00±0.05; and for GD, h2 was 0.00±0.08. The genetic trend for CI was -0.01 days/year. Finally, for CI, inbreeding depression was evident; this trait increased when inbreeding increased. These results indicate an important environmental influence on reproductive traits. The heritability estimate for CI suggests that little genetic progress could be achieved through selection. The evidence of inbreeding depression raises the need to control inbreeding to conserve this genetic resource.

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“…In terms of volume, milk losses and gains can be regarded from the perspective of pre-22 months; 22-25 months and post 25 months AFC. At an AFC of less than 22 months, 590-800 kg losses in the first 305 day lactation have been reported by (Elahi Torshizi, 2016) and (Pirlo, 2011). Ettema (2004) included pre-23 months in his study and reports a 320 kg loss in the first lactation: the lower volume lost is most likely because the cows at 22-23 months were included in the calculation.…”

Section: Milk Yieldmentioning

confidence: 95%

Age at first calving in dairy cows: which months do you aim for to maximise productivity?

Steele

2020

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The age at which a cow calves for the first time is a key indicator of the quality of youngstock management. Rate of growth in the heifer until she is inseminated, conceives and subsequently calves 9 months later can be affected by many factors. Nutrition quality and availability, disease risk (including parasitism), breed and insemination practices being only some of these influencing factors (Adamczyk, 2017;Bond, 2015;Davis Rincker, 2011 andMacDonald, 2005). A recent review of UK dairy herd data showed that the average (mean) age at first calving (AFC) was 29 months (median 28 months) (Eastham, 2018). This seemed significantly greater than the target of 22-24 months that is often quoted in press. Although there have been publications to summarise the performance effects of varying the AFC, few have concentrated on yield and reproduction together, in the same article and included data from more than one country. PICO questionIn dairy cattle, which months should producers target age at first calving in order to maximise milk yield, minimize risk of non-voluntary culling and optimize fertility? Clinical bottom line Category of research question RiskThe number and type of study designs reviewed Seventeen papers were critically reviewed: 15 sets of case series, one review of case series and cohort studies and one randomised control trial, summarising over 2.4 million individual cow records Strength of evidence Strong Outcomes reported An optimum range of age at first calving (AFC) on dairy farms appears to be 22-25 months inclusive. Lower or higher than this figure can bring lower first lactation 305 day and lifetime milk yields, lower fertility and lower chances of surviving to a second lactation. Achieving an AFC of 22-25 months can bring the highest economic return to dairies Conclusion Age at first calving is a useful and key performance parameter to measure in dairy cattle. Achieving a range of 22-25 months at first calving can help to optimise both long term milk yield, fertility and longevity within the herd How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient's circumstances and owners' values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care. Veterinary EvidenceThere are 17 articles recorded in this Knowledge Summary. They reflect a geographical range representative of Holstein-Friesian (Bos taurus) dairy cows in Europe, Asia and North America. There is one review of case series articles, including 125 referenced articles from 1979-2014. There is one randomised control trial, focusing on growth rates and AFC. The other 15 papers are case series, including data collected from dairy software on farms mostly invol...

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Effects of season and age at first calving on genetic and phenotypic characteristics of lactation curve parameters in Holstein cows

Cited by 30 publications

References 37 publications

Classification and prediction of milk yield level for Holstein Friesian cattle using parametric and non-parametric statistical classification models

Classification and prediction of milk yield level for Holstein Friesian cattle using parametric and non-parametric statistical classification models

Genetic parameters and trends for reproductive traits in Blanco Orejinegro cattle from Colombia

Age at first calving in dairy cows: which months do you aim for to maximise productivity?

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