Effect of dietary protein content on animal production and blood metabolites of dairy cows during lactation

Law, R.A.; Young, F.J.; Patterson, D. C.; Kilpatrick, D. J.; Wylie, A.R.G.; Mayne, C. S.

doi:10.3168/jds.2008-1155

Cited by 109 publications

(136 citation statements)

References 19 publications

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“…In agreement with our study, curvilinear milk yield and energy-corrected milk responses to, respectively, ME and NE L were reported in the meta-analyses of Huhtanen and Nousiainen (2012) and Jensen et al (2015). Increased MP supply may increase the partition of energy towards milk because it was associated with a small, but significant, decrease in EB, as previously reported (Ørskov et al, 1987;Law et al, 2009;Brun-Lafleur et al, 2010). A key question with respect to milk responses relates to the presence or not of interactions between NE L and MP supply.…”

Section: Milk Responsessupporting

confidence: 91%

Milk yield and milk composition responses to change in predicted net energy and metabolizable protein: a meta-analysis

Daniel

Friggens

Chapoutot

et al. 2016

animal

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Using a meta-analysis of literature data, this study aimed to quantify the dry matter (DM) intake response to changes in diet composition, and milk responses (yield, milk component yields and milk composition) to changes in dietary net energy for lactation (NE L ) and metabolizable protein (MP) in dairy cows. From all studies included in the database, 282 experiments (825 treatments) with experimentally induced changes in either NE L or MP content were kept for this analysis. These treatments covered a wide range of diet characteristics and therefore a large part of the plausible NE L and MP contents and supplies that can be expected in practical situations. The average MP and NE L contents were, respectively (mean ± SD), 97 ± 12 g/kg DM and 6.71 ± 0.42 MJ/kg DM. On a daily supply basis, there were high between-experiment correlations for MP and NE L above maintenance. Therefore, supplies of MP and NE L above maintenance were, respectively, centred on MP supply for which MP efficiency into milk protein is 0.67, and NE L above maintenance supply for which the ratio of NE L milk/NE L above maintenance is 1.00 (centred variables were called MP 67 and NE L100 ). The majority of the selected studies used groups of multiparous Holstein-Friesian cows in mid lactation, milked twice a day. Using a mixed model, between-and within-experiment variation was split to estimate DM intake and milk responses. The use of NE L100 and MP 67 supplies substantially improved the accuracy of the prediction of milk yield and milk component yields responses with, on average, a 27% lower root mean square error (RMSE) relative to using dietary NE L and MP contents as predictors. For milk composition (g/kg), the average RMSE was only 3% lower on a supply basis compared with a concentration basis. Effects of NE L and MP supplies on milk yield and milk component yields responses were additive. Increasing NE L supply increases energy partitioning towards body reserve, whereas increasing MP supply increases the partition of energy towards milk. On a nitrogen basis, the marginal efficiency decreases with increasing MP supply from 0.34 at MP 67 = −400 g/day to 0.07 at MP 67 = 300 g/day. This difference in MP 67 supply, assuming reference energy level of NE L100 = 0, equates to a global nitrogen efficiency decrease from 0.82 to 0.58. The equations accurately describe DM intake response to change in dietary contents and milk responses to change in dietary supply and content of NE L and MP across a wide range of dietary compositions.Keywords: dairy cow, milk composition, energy, protein, meta-analysis Implications Current feed evaluation systems are not suitable to predict animal responses to dietary changes. This paper quantifies average dry matter intake, milk yield and milk composition responses to change in net energy and metabolizable protein. The equations were derived from a meta-analysis of literature studies, which assembles a large number of dairy cow rations with a large range in dietary net energy and metabolizable protein contents.

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Section: Milk Responsessupporting

confidence: 91%

Milk yield and milk composition responses to change in predicted net energy and metabolizable protein: a meta-analysis

Daniel

Friggens

Chapoutot

et al. 2016

animal

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“…The much higher response and variation in urinary N output compared with faecal N excretion clearly presents an opportunity to manipulate diets to reduce N excretion in urine in particular. It is pertinent to note here that, although reduced dietary N concentration is a key mitigation strategy to decrease urinary N output in cattle, reduced dietary N levels may impair feed intake and production (Law et al, 2009;Brun-Lafleur et al, 2010). This lowered productivity may actually deteriorate the efficiency of conversion of feed into milk or meat.…”

Section: Diet Effects On Level Of N In Urinementioning

confidence: 99%

Diet effects on urine composition of cattle and N2O emissions

Dijkstra

Oenema

Groenigen

et al. 2013

Animal

311

215

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Ruminant production contributes to emissions of nitrogen (N) to the environment, principally ammonia (NH 3 ), nitrous oxide (N 2 O) and di-nitrogen (N 2 ) to air, nitrate (NO 3 2 ) to groundwater and particulate N to surface waters. Variation in dietary N intake will particularly affect excretion of urinary N, which is much more vulnerable to losses than is faecal N. Our objective is to review dietary effects on the level and form of N excreted in cattle urine, as well as its consequences for emissions of N 2 O. The quantity of N excreted in urine varies widely. Urinary N excretion, in particular that of urea N, is decreased upon reduction of dietary N intake or an increase in the supply of energy to the rumen microorganisms and to the host animal itself. Most of the N in urine (from 50% to well over 90%) is present in the form of urea. Other nitrogenous components include purine derivatives (PD), hippuric acid, creatine and creatinine. Excretion of PD is related to rumen microbial protein synthesis, and that of hippuric acid to dietary concentration of degradable phenolic acids. The N concentration of cattle urine ranges from 3 to 20 g/l. High-dietary mineral levels increase urine volume and lead to reduced urinary N concentration as well as reduced urea concentration in plasma and milk. In lactating dairy cattle, variation in urine volume affects the relationship between milk urea and urinary N excretion, which hampers the use of milk urea as an accurate indicator of urinary N excretion. Following its deposition in pastures or in animal houses, ubiquitous microorganisms in soil and waters transform urinary N components into ammonium (NH 4 1 ), and thereafter into NO 3 2 and ultimately in N 2 accompanied with the release of N 2 O. Urinary hippuric acid, creatine and creatinine decompose more slowly than urea. Hippuric acid may act as a natural inhibitor of N 2 O emissions, but inhibition conditions have not been defined properly yet. Environmental and soil conditions at the site of urine deposition or manure application strongly influence N 2 O release. Major dietary strategies to mitigating N 2 O emission from cattle operations include reducing dietary N content or increasing energy content, and increasing dietary mineral content to increase urine volume. For further reduction of N 2 O emission, an integrated animal nutrition and excreta management approach is required.Keywords: nitrogen, urine, cattle, nitrous oxide, mitigation ImplicationsCattle contribute to global warming through emission of nitrous oxide (N 2 O) from urine and faeces. Urinary nitrogen (N) is much more susceptible to gaseous losses than faecal N. To reduce urinary N excretion and N 2 O emission and improve N efficiency of cattle, dietary levels of N should be decreased and an optimal balance between N and energy substrates in the diet should be aimed at. Increasing urine volume by increased dietary mineral contents appears a promising N 2 O mitigation strategy, particularly in pasture. Further reduction of effective mitigation strategies...

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Section: Cp and Intakementioning

confidence: 99%

“…Contemporary evidence for high-yielding dairy cows, however, indicates that reductions in intake are likely to be modest at CP levels at or above 140 g/kg DM (e.g. Broderick, 2003; Colmenero and Broderick, 2006;Law et al, 2009a;Lee et al, 2011) and could be at least partially offset by either improving the digestibility of the UDP component of the diet (Noftsger and St-Pierre, 2003), by increasing fermentable metabolisable energy (FME) (Herrera-Saldana et al, 1990), and/or by increasing the overall ME of the diet (thereby altering the ME : MP ratio).Physiological status (stage of lactation) Dietary requirements to support milk production vary during lactation reflecting changes in milk yield, appetite and endocrine regulation of nutrient partitioning between tissues and the mammary gland. Scope, therefore, may exist to modify dietary protein levels at different stages during lactation in order to increase the efficiency of N utilisation and to maximise milk yields.…”

mentioning

confidence: 99%

Reducing dietary protein in dairy cow diets: implications for nitrogen utilization, milk production, welfare and fertility

Sinclair

Garnsworthy

Mann

et al. 2014

Animal

116

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In light of increasing global protein prices and with the need to reduce environmental impact of contemporary systems of milk production, the current review seeks to assess the feasibility of reducing levels of dietary CP in dairy cow diets. At CP levels between 140 and 220 g/kg DM there is a strong positive relationship between CP concentration and dry matter intake (DMI). However, such effects are modest and reductions in DMI when dietary CP is below 180 g/kg DM can be at least partially offset by improving the digestibility and amino acid profile of the undegradable protein (UDP) component of the diet or by increasing rumen fermentable energy. Level and balance of intestinally absorbable amino acids, in particular methionine and lysine, may become limiting at lower CP concentrations. In general the amino acid composition of microbial protein is superior to that of UDP, so that dietary strategies that aim to promote microbial protein synthesis in the rumen may go some way to correcting for amino acid imbalances in low CP diets. For example, reducing the level of NDF, while increasing the proportion of starch, can lead to improvements in nitrogen (N) utilisation as great as that achieved by reducing dietary CP to below 150 g/kg. A systematic review and meta-analysis of responses to rumen protected forms of methionine and lysine was conducted for early/mid lactation cows fed diets containing ⩽150 g CP/kg DM. This analysis revealed a small but significant ( P = 0.002) increase in milk protein yield when cows were supplemented with these rumen protected amino acids. Variation in milk and milk protein yield responses between studies was not random but due to differences in diet composition between studies. Cows fed low CP diets can respond to supplemental methionine and lysine so long as DMI is not limiting, metabolisable protein (MP) is not grossly deficient and other amino acids such as histidine and leucine do not become rate limiting. Whereas excess dietary protein can impair reproduction and can contribute to lameness, there is no evidence to indicate that reducing dietary CP levels to around 140 to 150 g CP/kg DM will have any detrimental effect on either cow fertility or health. Contemporary models that estimate MP requirements of dairy cows may require refinement and further validation in order to predict responses with low CP diets.Keywords: dairy cow, CP, milk yield, fertility, health ImplicationsReducing CP levels to around 140 g/kg DM in dairy cow diets increases the efficiency of N capture and reduces N excretion to the environment. Predicting milk yield responses, however, is complicated by the paucity of data for contemporary high-yielding cows. However, dietary strategies should aim to maximize the yield of microbial protein. Responses to additional essential amino acids such as methionine and lysine are variable and difficult to predict. No detrimental effects of low (i.e. 140 to 150 g CP/kg DM) CP diets on cow health and fertility are anticipated, but these require confirmation in contemporary hig...

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Effect of dietary protein content on animal production and blood metabolites of dairy cows during lactation

Cited by 109 publications

References 19 publications

Milk yield and milk composition responses to change in predicted net energy and metabolizable protein: a meta-analysis

Milk yield and milk composition responses to change in predicted net energy and metabolizable protein: a meta-analysis

Diet effects on urine composition of cattle and N2O emissions

Reducing dietary protein in dairy cow diets: implications for nitrogen utilization, milk production, welfare and fertility

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