Effect of genetic merit, milk yield, body condition and lactation number on in vitro oocyte development in dairy cows

Snijders, S.; Dillon, P.; O'Callaghan, D.; Boland, M.P.

doi:10.1016/s0093-691x(00)00244-2

Cited by 132 publications

(108 citation statements)

References 18 publications

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“…fertilisation of oocytes from high-compared to mediumgenetic merit cows resulted in significantly lower blastocyst yield in vitro, irrespective of milk production as such (Snijders et al, 2000). However, the environmental factors have at least an equivalent importance to the genetic ones.…”

Section: Milk Production and Reproductive Performancementioning

confidence: 98%

Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding

Friggens

Disenhaus

Petit

2010

Animal

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There has been a significant decline in the reproductive performance of dairy cattle in recent decades. Cows, take longer time to return to the oestrus after calving, have poorer conception rates, and show fewer signs of oestrus. Achieving good reproductive performance is an increasing challenge for the dairy producer. In this study we focus on understanding the overall biological phenomena associated with nutritional sub-fertility rather than the underlying multiplicity of physiological interactions (already described in a number of recent studies). These phenomena are important because they represent the natural adaptations of the animal for dealing with variations in the nutritional environment. They can also be used to monitor and modulate reproductive performance on-farm. There is an underlying trade-off between two aspects of reproduction: investment in the viability of the current calf and investment in future offspring. As the investment in, and viability of, the current calf is related to maternal milk production, we can expect that level of milk production per se has effects on subsequent reproductive performance (investment in future offspring). Lactating cows have a lower proportion of viable embryos, which are of poorer quality, than do non-lactating cows. The same applies to high-compared to medium-genetic merit cows. Another important biological property is the adaptive use of body reserves in support of reproduction. Orchestrated endocrine changes in pregnancy and lactation facilitate the deposition of body lipid during pregnancy and mobilisation in early lactation. When the cow fails to accumulate the reserves she needs to safeguard reproduction she delays committing to further reproductive investment. But how does the cow 'know' that she is failing in energy terms? We argue that the cow does this by 'monitoring' both the body fat mobilisation and body fatness. Excessive body fat mobilisation indicates that current conditions are worse than expected. Body fatness indicates the future ability of the cow to safeguard her reproductive investment is compromised. Both delay further reproductive commitment. The relationship between reproductive performance and; milk production as an index of maternal investment, body fatness as an index of ability to safeguard reproductive investment, and body fat mobilisation as an index of the current nutritional environment -are examined. Nutritional strategies that seek to modulate body mobilisation and the endocrine environment by use of glucogenic and lipogenic diets, and the use of in-line progesterone profiles to monitor reproductive status are then discussed in this biological context.

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Section: Milk Production and Reproductive Performancementioning

confidence: 98%

Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding

Friggens

Disenhaus

Petit

2010

Animal

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“…Several lines of evidence suggest that this may compromise oocyte quality. Snijders et al (2000) found that oocytes derived from high-yielding cows formed fewer blastocysts than those from medium genetic merit animals. This was related, in part, to BCS, with a lower success rate when the BCS of the donor was ,2.5.…”

Section: Effects Of Lipid Metabolism On the Reproductive Tract Ovarymentioning

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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“…Oocytes retrieved from high genetic merit cows, irrespective of their milk production value, resulted in significantly lower blastocyst yields in vitro (Snijders et al, 2000). This suggests possible adverse effects on fertility of the enforced genetic selection towards milk production.…”

Section: Introductionmentioning

confidence: 99%

The consequences of metabolic changes in high-yielding dairy cows on oocyte and embryo quality

Leroy

Soom

Opsomer

et al. 2008

Animal

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Unsatisfactory reproductive performance in dairy cows, such as reduced conception rates, in addition to an increased incidence of early embryonic mortality, is reported worldwide and has been associated with a period of negative energy balance (NEB) early post partum. Typically, NEB is associated with biochemical changes such as high non-esterified fatty acid (NEFA), high b-hydroxybutyrate (b-OHB) and low glucose concentrations. The concentrations of these and other metabolites in the follicular fluid (FF) of high-yielding dairy cows during NEB were determined and extensively analyzed, and then were replicated in in vitro maturation models to investigate their effect on oocyte quality. The results showed that typical metabolic changes during NEB are well reflected in the FF of the dominant follicle. However, the oocyte seems to be relatively isolated from extremely elevated NEFA or very low glucose concentrations in the blood. Nevertheless, the in vitro maturation models revealed that NEB-associated high NEFA and low glucose levels in the FF are indeed toxic to the oocyte, resulting in deficient oocyte maturation and developmental competence. Induced apoptosis and necrosis in the cumulus cells was particularly obvious. Furthermore, maturation in saturated free fatty acid-rich media had a carry-over effect on embryo quality, leading to reduced cryotolerance of day 7 embryos. Only b-OHB showed an additive toxic effect in moderately hypoglycemic maturation conditions. These in vitro maturation models, based on in vivo observations, suggest that a period of NEB may hamper the fertility of high-yielding dairy cows through increased NEFA and decreased glucose concentrations in the FF directly affecting oocyte quality. In addition to oocyte quality, these results also demonstrate that embryo quality is reduced following an NEB episode. This important observation may be linked to the typical diet provided to stimulate milk yield, or to physiological adaptations sustaining the high milk production. Research into this phenomenon is ongoing.

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Effect of genetic merit, milk yield, body condition and lactation number on in vitro oocyte development in dairy cows

Cited by 132 publications

References 18 publications

Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding

Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding

Associations between lipid metabolism and fertility in the dairy cow

The consequences of metabolic changes in high-yielding dairy cows on oocyte and embryo quality

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