Recent research on the effects of excess dietary nitrogen on the fertility of dairy cows

Laven, Richard; Scaramuzzi, R. J.; Wathes, D C; Peters, A. R.; Parkinson, T. J.

doi:10.1136/vr.160.11.359

Cited by 26 publications

(30 citation statements)

References 13 publications

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“…The increase in ammonia concentrations may also occur as a result of accumulation of triacylglycerides and inhibition of ureagenesis during the transition period in dairy cows [169]. A high concentration of circulating urea and ammonia in the bloodstream of cows is associated with reduced fertility [83,128,160]. Exposure of oocytes in antral follicles to high levels of ammonia concentrations during fertilization may hamper cleavage and blastocyst formation [137].…”

Section: Reproductive Endocrinology and Hormonal Adaptations In Cows mentioning

confidence: 99%

Tissues, Metabolic Pathways and Genes of Key Importance in Lactating Dairy Cattle

Nayeri

Stothard

2016

Springer Science Reviews

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Milk and dairy products are valuable sources of food for humans. Increased milk yield and changes in milk composition in dairy cows have been achieved through a variety of means including better nutrition, management and genetic selection. This selection can be performed without consideration of the specific genes and genetic variation involved. However, association analysis using dense SNP genotyping panels provides an approach for identifying genomic regions affecting milk production. Coupling physiological and metabolic information with association analysis results can provide greater insight into the specific genetic variants and molecular mechanisms affecting production traits as well as the potential effects of these variants on fertility in dairy cattle. To this end, this review highlights key tissues, metabolic pathways and genes of importance in lactating dairy cattle, particularly early in lactation. Physiological and metabolic adaptations in three key tissues (adipose, mammary gland and liver) are discussed, followed by the important endocrine adaptations during negative energy balance. Key genes mediating metabolic and endocrine adaptations are also highlighted. Finally, genes that account for variation in production traits are presented in relation to the tissues and processes described. Knowledge of the genes and pathways involved will be important for ongoing efforts aimed at finding other genes and variants that contribute to milk production and fertility traits. Also, a better understanding of the molecular basis of these traits may lead to more accurate genomic predictions.

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Section: Reproductive Endocrinology and Hormonal Adaptations In Cows mentioning

confidence: 99%

Tissues, Metabolic Pathways and Genes of Key Importance in Lactating Dairy Cattle

Nayeri

Stothard

2016

Springer Science Reviews

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“…Buscando uma explicação para estes efeitos, Laven et al (2007) concluíram que vacas são capazes de se adaptar a dietas contendo alto nitrogênio. Entretanto, estas dietas podem causar redução da fertilidade quando introduzidas em períodos críticos, por exemplo, de inseminação, o que não ocorre quando introduzidas em estágios mais iniciais.…”

Section: Resultsunclassified

Dietas com nitrogênio não-proteico para fêmeas bovinas superovuladas sem prévia adaptação durante curto tempo e em diferentes fases do ciclo estral

et al. 2010

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RESUMO -Objetivou-se neste estudo avaliar o efeito do fornecimento, sem prévia adaptação, durante curto tempo e em diferentes fases do ciclo estral, de dietas contendo nitrogênio não-proteico (NNP) na produção, na qualidade e no grau de desenvolvimento de embriões recuperados em fêmeas bovinas superovuladas. Sessenta e oito vacas Nelore foram distribuídas em três grupos: um controle e dois com fornecimento de ureia antes (UA = do dia -5 ao dia 0) e após (UD = dia 0 ao dia 5) a inseminação artificial. As vacas foram mantidas em pastagem e receberam concentrado (3,0 kg/animal/dia) durante 16 dias.Foram formulados dois concentrados, e as dietas totais (concentrado e consumo estimado de pastagem) apresentaram 12,0% (dieta controle) e 14,6% (dieta NNP) de proteína bruta (PB). As vacas foram sincronizadas, superovuladas e inseminadas. Sete dias (dia 7) após a inseminação (dia 0), realizou-se a colheita e análise dos embriões. Amostras de sangue foram coletadas nos dias -5, 0 e 5 para determinação da concentração de nitrogênio ureico plasmático (NUP), glicose, insulina e progesterona. A época de fornecimento de ureia influenciou as concentrações médias de NUP nos dias -5, 0 e 5, mas não tiveram efeito nas concentrações de glicose, insulina e progesterona. O período de fornecimento da ureia teve efeito na porcentagem de mórulas compactas em relação ao total de estruturas (UA = 51,4 vs. UD = 15,3%), em relação ao total de oócitos fecundados (UA = 62,5 vs. UD = 30,6%) e em relação ao total de embriões viáveis (UA = 68,8 vs. UD = 38,6%). No grupo que recebeu ureia depois da inseminação artificial, houve redução de 70,2% da proporção de mórulas compactas por total de estruturas em relação ao grupo que recebeu ureia antes da inseminação. Dietas com nitrogênio não-proteico fornecidas imediatamente após a inseminação promovem aceleração do desenvolvimento embrionário inicial.Palavras-chave: embrião, Nelore, nitrogênio ureico plasmático (NUP), proteína bruta, ureia Effect of short term non-protein nitrogen feeding for superovulated beef cows without previous adaptation and at different periods of the oestrus cycleABSTRACT -The aim of this study was to evaluate the effects of short term non-protein nitrogen feeding at different periods of the oestrus cycle in superovulated cows, without previous adaptation, on yield, quality and development degree of recovered embryos. A total of sixty-eight Nelore cows were distributed in three groups: the control group (C) and two groups with urea supply before (UB; urea supply from day -5 to day 0) and after (UA; supply from day 0 to day 5) artificial insemination.Animals were kept grazing and received 3.0 kg/animal/day of concentrate during 16 days. Two concentrates were formulated and the total diets (concentrate and estimate forage intake) showed 12.0% (control diet) and 14.6% (non-protein diet) of crude protein. Animals were synchronized, superovulated and inseminated. The embryos were collected and analysed seven days (day 7)after insemination (day 0). Blood samples were collected on day...

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“…Nevertheless such diets, particularly those with high levels of effective rumen degradable protein (ERDP), have also been associated with decreased fertility (Laven & Drew, 1999). However, the evidence for an effect of high intakes of ERDP on fertility is inconclusive, particularly for cattle fed normal commercial diets, with many studies showing little or no effect of increased dietary nitrogen on fertility (Laven et al 2007). …”

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confidence: 99%

“…Urea is commonly suggested to be the primary toxic by-product (e.g. However, Laven et al (2007) concluded that much of the effect of increased intakes of degradable protein was probably mediated by ammonia rather than urea, and that in such cases plasma ammonia concentration was more closely correlated with reduced fertility than plasma urea concentration. However, Laven et al (2007) concluded that much of the effect of increased intakes of degradable protein was probably mediated by ammonia rather than urea, and that in such cases plasma ammonia concentration was more closely correlated with reduced fertility than plasma urea concentration.…”

mentioning

confidence: 99%

“…The first was a comparison of two studies which investigated the effect of intakes of quickly degradable protein (in the form of urea) on the yield and quality of embryos. The second rationale stated by Laven et al (2007) was the lack of evidence, in cows fed diets based on grazed grass, for high dietary nitrogen intakes (particularly in the form of nitrates) having a deleterious effect on fertility (Kenny et al 2001;Laven et al 2002 ;Ordonez et al 2007). Whereas reported that feeding their diet for 13 d prior to oocyte collection significantly reduced oocyte cleavage and blastocyst production, Dawuda et al (2002) reported that feeding their diet for 17 d prior to embryo collection had no effect on either the number or the quality of embryos recovered, thus suggesting that plasma ammonia concentration was more important than urea concentration in determining whether a diet had a significant effect on embryo quality.…”

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confidence: 99%

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An analysis of the relationship between plasma urea and ammonia concentration in dairy cattle fed a consistent diet over a 100-day period

Laven

Wathes

Lawrence

et al. 2007

Journal of Dairy Research

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Measurement of plasma urea concentration is often used to identify a risk of dietary nitrogen-associated infertility. However, the use of plasma urea concentration in this way relies on it being an effective predictor for other potential toxic products associated with nitrogen metabolism (such as plasma or uterine ammonia). Recent research has shown that dietary nitrogen-associated infertility can be produced by diets which elevate plasma ammonia concentration without markedly increasing plasma urea concentration. Thus for cattle on different diets plasma urea concentration cannot be used to predict plasma ammonia concentration. This study evaluated whether plasma urea concentration could be used to predict plasma ammonia concentration in cattle kept on consistent diets. Data were analysed from a study where 42 cattle had been fed a control diet or the control diet plus 250 g urea per cow per day and had had weekly measurements of post-prandial plasma urea and ammonia concentrations. This analysis found that over a 100-d period, plasma urea concentration was relatively constant and unaffected by time while plasma ammonia concentration was significantly more variable, being affected by time since the study started, and whether cows began the study in the first or second group. Correlation between plasma ammonia and urea was limited; plasma urea concentration explained only 3.8% of the variation in plasma ammonia concentration. These data suggest that, even in cows on consistent diets, plasma urea concentration is not a good predictor of plasma ammonia, and that a simple urea threshold may not accurately identify the risk of dietary nitrogen-associated infertility.

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Recent research on the effects of excess dietary nitrogen on the fertility of dairy cows

Cited by 26 publications

References 13 publications

Tissues, Metabolic Pathways and Genes of Key Importance in Lactating Dairy Cattle

Tissues, Metabolic Pathways and Genes of Key Importance in Lactating Dairy Cattle

Dietas com nitrogênio não-proteico para fêmeas bovinas superovuladas sem prévia adaptação durante curto tempo e em diferentes fases do ciclo estral

An analysis of the relationship between plasma urea and ammonia concentration in dairy cattle fed a consistent diet over a 100-day period

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