Reproductive performance and survival of Chinese Holstein dairy cows in central China

Wu, Jun; Wathes, D C; Brickell, J. S.; Yang, Liguo; Cheng, Zhangrui; Zhao, Hua; Xu, Yingyan; Zhang, S. J.

doi:10.1071/an11146

Cited by 21 publications

(23 citation statements)

References 39 publications

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“…An Italian study identified a mean AFC at 28.1 months of age (Pirlo et al, 2000) taken from a large heifer data set, but this data set excluded all heifers calving <20 and >36 months of age and therefore excluded older heifers. Other studies have also reported different average AFCs across the world (Ettema and Santos, 2004;Bach, 2011;Wu et al, 2012) and these studies have been based on either single or a few farms, limiting the exposure to different management systems and geographical regions. The present study represents one of the largest study to date, but it remains uncertain as to whether this truly reflects the UK situation, because a convenience sample was used to ensure data of sufficient quality.…”

Section: Discussionmentioning

confidence: 99%

The association between age at first calving and survival of first lactation heifers within dairy herds

Sherwin

Hudson

Henderson

et al. 2016

Animal

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The objective of this research was to evaluate the survival rate of primiparous heifers within a large sample of herds across the United Kingdom and specifically to assess the association between age at first calving (AFC) on their survival. Data from 437 herds were re-structured for analysis. Descriptive statistics were calculated, and a multilevel logistic regression model was used to explore factors associated with the risk of first lactation culling. Potential explanatory variables included AFC, herd size, culling rate within the whole herd, calving season, herd mean 305-day yield and herd mean calving interval. The mean within-herd culling rate for the primiparous heifers was 15.9%. The mean within-herd AFC was 29.6 months, with 35.9% of heifers having an AFC >30 months of age. Multivariable analysis revealed a negative association between survival rate of primiparous heifers and increasing AFC, and also associations with herd culling rate in older cows and calving season. This study highlights the importance of AFC for survival of primiparous heifers, as well as the need to address heifer wastage in herds with high culling rates.Keywords: age at first calving, heifers, longevity, culling ImplicationsThis study has identified that culling rate of primiparous heifers during first lactation varies greatly between farms and that the age at first calving (AFC) has a significant association with this. This study highlights the importance of maintaining an AFC of 23 to 24 months of age because prolonged AFC leads to a greater wastage of primiparous heifers with associated financial losses. IntroductionHeifer rearing is a key financial component of most dairy farms, with the rearing of replacements accounting for 15% to 20% of total dairy production costs (Heinrichs, 1993). The importance of replacement rate and the target number of replacements for each individual farm is dependent upon the culling rate of that particular farm. The annual culling rate within UK dairy herds has previously been reported to be between 22% and 25% (Esslemont and Kossaibati, 1997;Whitaker et al., 2000;Bell et al., 2010). Culls have traditionally been classified as voluntary or involuntary; however, another classification is 'forced culls' and 'economic culls'. Forced culls are those cows for which no possible productive future exists and economic culls are those cows for which a decision has been made that replacing them with another cow is a sensible economic option (Fetrow et al., 2006). As the majority of the culls on farm are economic (Orpin and Esslemont, 2010), this indicates that the incoming replacement animal needs to be a better financial option for the farm. Previous research highlights that the costs of rearing a replacement are not recovered until the second lactation (Archer et al., 2013), therefore it is imperative that replacement heifers survive to their second lactation.A variety of studies have recently investigated the survival rates of primiparous heifers. A study in Spain reported that 8.4% of 7768 Holstein heife...

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Section: Discussionmentioning

confidence: 99%

The association between age at first calving and survival of first lactation heifers within dairy herds

Sherwin

Hudson

Henderson

et al. 2016

Animal

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“…Fertility may be worse in first-lactation cows in comparison with older animals (e.g. Wu et al 2012), and they experience a higher incidence of delayed resumption of ovarian cyclicity (Wathes et al 2007a). Although most older cows have achieved mature body size, they also have a greater capacity for milk production.…”

Section: Age-related Influences On Fertilitymentioning

confidence: 99%

Mechanisms Linking Metabolic Status and Disease with Reproductive Outcome in the Dairy Cow

Wathes

2012

Reprod Domestic Animals

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Contents Culling for infertility remains the main reason for disposal of dairy cows, limiting productive lifespan. In extreme cases, ovulation is inhibited, preventing the possibility of conception. More often cows do conceive, but fail to remain pregnant owing to intrinsic problems in the embryo and/or to a poor‐quality reproductive tract environment. Both aspects have a genetic component and are also influenced by management practices affecting nutrition and health. The relative importance of these factors varies among heifers, first‐lactation and older cows. A common theme, however, is that an internal signalling system exists which reduces fertility when the cow is in an unsuitable metabolic state to sustain a pregnancy. This may be directly related to nutrient shortage caused by inadequate feed intake, or because available nutrients are being prioritized towards growth or milk production, away from reproduction. Evidence is presented for the involvement of the somatotrophic axis (GH, IGF1, insulin, IGFBP2) and leptin as key metabolic signalling molecules. Another emerging theme is the interaction between metabolism and disease that affects the fertility. Common examples include (i) calf diseases causing inadequate heifer growth and increased age at first calving; (ii) poor peripartum energy status reducing the capacity of the uterus to involute and mount an effective immune response, thereby increasing the likelihood of endometritis; and (iii) development of mastitis after conception, a contributory factor to both early and late embryo mortality. Finally, recent evidence suggests that times of metabolic stress cause mitochondrial damage that also contributes to a reduction in longevity.

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“…This is particularly critical in systems based on a seasonal calving pattern and is still economically beneficial in all-year calving herds. In reality, however, typical calving intervals in many countries are over 400 days, and approximately 20% of cows are culled in each lactation, with failure to conceive the main reason (Brickell and Wathes 2011;Wu et al 2012). There is a widespread acceptance that the fertility of modern cows is poor and needs to be improved in future by: (1) altering the genetic breeding goals to include non-production traits (Berry et al 2003); and (2) improving management, in particular through better nutrition (Beever 2006).…”

Section: Introductionmentioning

confidence: 99%

Associations between lipid metabolism and fertility in the dairy cow

Wathes

Clempson

Pollott

2013

Reprod. Fertil. Dev.

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Abstract. Dairy cows mobilise body tissues to support milk production and, because glucose supplies are limited, lipids are used preferentially for energy production. Lipogenic activity is switched off and lipolytic mechanisms in adipose tissue increase through changes in the expression of several key enzymes. This results in a loss of body condition, together with high circulating concentrations of non-esterified fatty acids. Changes in the synthesis, secretion and signalling pathways of somatotrophic hormones (insulin, growth hormone, insulin-like growth factor 1) and adipokines (e.g. leptin) are central to the regulation of these processes. A high reliance on fatty acids as an energy source in the peripartum period causes oxidative damage to mitochondria in metabolically active tissues, including the liver and reproductive tract. The expression of genes involved in insulin resistance (PDK4, AHSG) is increased, together with expression of TIEG1, a transcription factor that can induce apoptosis via the mitochondrial pathway. Polymorphisms in TFAM and UCP2, two autosomal mitochondrial genes, have been associated with longevity in dairy cows. Polymorphisms in many other genes that affect lipid metabolism also show some associations with fertility traits. These include DGAT1, SCD1, DECR1, CRH, CBFA2T1, GH, LEP and NPY. Excess lipid accumulation in oocytes and the regenerating endometrium reduces fertility via reductions in embryo survival and increased inflammatory changes, respectively.

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Reproductive performance and survival of Chinese Holstein dairy cows in central China

Cited by 21 publications

References 39 publications

The association between age at first calving and survival of first lactation heifers within dairy herds

The association between age at first calving and survival of first lactation heifers within dairy herds

Mechanisms Linking Metabolic Status and Disease with Reproductive Outcome in the Dairy Cow

Associations between lipid metabolism and fertility in the dairy cow

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