The aim of this work was to determine the effect of 3-nitrooxypropanol (3-NOP) on the enteric methane (CH4) emissions and performance of lactating dairy cows when mixed in with roughage or ...incorporated into a concentrate pellet. After 2 pretreatment weeks without 3-NOP supplementation, 30 Holstein Friesian cows were divided into 3 homogeneous treatment groups: no additive, 3-NOP mixed in with the basal diet (roughage; NOPbas), and 3-NOP incorporated into a concentrate pellet (NOPconc). The pretreatment period was followed by a 10-wk treatment period in which the NOPbas and NOPconc cows were fed 1.6 g of 3-NOP/cow per day. After the treatment period, a 2-wk washout period followed without 3-NOP supplementation. The CH4 emissions were measured using a GreenFeed unit (C-Lock Inc., Rapid City, SD) installed in a freestall with cubicles during the entire experimental period. On average for the total treatment period and compared with the no-additive group, CH4 production (g/d) was 28 and 23% lower for NOPbas and NOPconc, respectively. Methane yield (g/kg of dry matter intake) and methane intensity (g/kg of milk) were 23 and 24% lower for NOPbas, respectively, and 21 and 22% lower for NOPconc, respectively. No differences were found between NOPbas and NOPconc. Moreover, supplying 3-NOP did not affect total dry matter intake, milk production, or milk composition. The results of this experiment show that 3-NOP can reduce enteric CH4 emissions of dairy cattle when incorporated into a concentrate pellet and that this reduction is not different from the effect of mixing in 3-NOP with the basal diet (roughage). This broadens the possibilities for using 3-NOP in the dairy sector worldwide, as it is not always feasible to provide an additive mixed in with the basal diet.
During growth, pigs convert plant protein into animal protein. The major part of the ingested protein is excreted via manure, with potential nitrogen (N) losses to the environment. To limit N losses ...and increase sustainability of pork production, the efficiency of protein conversion should be maximized. The aim of this paper is to critically evaluate diet and management strategies linked with N efficiency. Besides nutrition, we discuss three management strategies observed in science and in practice to be linked with improved N efficiency: genetic selection, castration and slaughter weight. Because diet has a marked effect on eventual N losses, it must also be taken into account when evaluating management strategies. A reductionist approach, such as feeding the same diet across all management treatments, may overestimate the effect of a management strategy and eventually lead to incorrect conclusions. The amount of excreted N depends on the amount of ingested N, the amount of absorbed N, the amino acid (AA) balance in the diet and the animal's N and AA requirements. Daily multiphase feeding adapted to the individual animal's AA needs is likely to be the most N efficient. For animals housed in groups, phase feeding is necessary. When combined with periods of temporary AA restriction, N efficiency can be further improved. Specific AA consumption must be balanced by applying the ideal protein concept. With better knowledge of the requirements of individual animals and the commercial availability of certain AAs, the total dietary CP level can be lowered within limits. Further research is needed on the minimal CP level that allows maximal performance. For this end a useful parameter may be the ratio of standardized ileal digestible (SID) lysine : apparent total tract digestible CP level. By combining optimal nutrition and management, a whole body N efficiency approaching 60% may be achievable in the near future.
Seven feed additives (i.e., quillaja saponins, fumaric acid, garlic oil, fish oil, cinnamaldehyde, monensin, and medium chain fatty acids (MCFA)), were evaluated for their effects on CH₄ inhibition ...in vitro in combination with four substrates: concentrate (CON), grass silage (GS), maize silage (MS) and the mixture of CON+GS+MS (300:350:350 (dry matter, DM), MIX), all feeds regularly used in dairy cattle feeding. Substrates and additives were incubated in a batch incubation system containing buffered rumen fluid for 24h. Cinnamaldehyde had an interaction with substrate for CH₄ inhibition, volatile fatty acid (VFA) production and inhibition of CH₄ relative to VFA. For fumaric acid, interactions occurred for CH₄ relative to VFA. Fish oil, quillaja saponins and MCFA had additive×substrate interactions for inhibition of CH₄ and VFA production, but they had no interactions for CH₄ relative to VFA. Garlic oil had no interaction with substrates for CH₄ production and CH₄ relative to VFA, but had interactions for VFA production. Monensin had substrate×additive interactions for CH₄ and VFA production and CH₄ relative to VFA. Monensin and quillaja saponins were more effective at inhibiting CH₄ production when combined with GS and MS than with CON. Fish oil had higher inhibition when combined with CON and GS than with MS. The MCFA had higher inhibitions when combined with MS and were lowest with CON, the combination with GS was intermediate and differed from both other substrates. Cinnamaldehyde and MCFA decreased, whereas fumaric acid increased the total VFA production. No other additive affected total VFA production. As a general CH₄ mitigation strategy, fumaric acid, garlic oil and fish oil were better in combination with CON. Monensin was more effective in combination with GS, and quillaja saponins were more effective when combined with MS. Cinnamaldehyde and MCFA strongly inhibited fermentation which impaired appropriate evaluation of the most promising combination. Despite additive×substrate interactions, CH₄ and VFA production in incubations with CON, GS and MS did not differ from the weighted average of incubations with single substrates with or without additives. Hence no synergism between additive and substrate combinations seemed to exist. Results clearly indicate interactions between additives and substrates. However, it is unlikely that this interaction is the origin of often variable results among in vitro studies.
The chemical composition and the energy and protein value of five batches of condensed distillers solubles (CDS) originating from wheat were determined. The net energy for lactation (NEL) was derived ...from digestion coefficients obtained with sheep. The true protein digested in the small intestine (DVE) and the rumen degradable protein balance (OEB) were based on the rumen degradation rate (kdD), the rumen undegradable fraction (U) and intestinal digestibility of undegraded protein (%DVBE) predicted by regression equations derived from a data set of 28 protein feeds with kdD, U and %DVBE determined in situ. The CDS is a by-product with a high, but very variable CP content (238 to 495 g/kg DM). The CP contained on average 81% amino acids, with glutamine as main component (on average 21.8% of CP) and a relatively good lysine proportion (3.0%). Further, CDS contains quite a lot of crude fat (mean±SD: 71±14 g/kg DM), glycerol (95±52 g/kg DM) and sugars (123±24 g/kg DM) resulting in a high organic matter digestibility (88.6±3.0%) and high NEL content (8.3±0.4 MJ/kg DM). The protein value showed a large variation, with DVE ranging from 122 to 244 g/kg DM and OEB from 50 to 204 g/kg DM. Wheat CDS is a rich source of minerals and trace elements with exception of calcium.
Milk fatty acid (MFA) have already been used to model methane (CH4) emissions from dairy cows. However, the data sets used to develop these models covered limited variation in dietary conditions, ...reducing the robustness of the predictions. In this study, a data set containing 140 observations from nine experiments (41 Holstein cows) was used to develop models predicting CH4 expressed as g/day, g/kg dry matter intake (DMI) and g/kg milk. The data set was divided into a training (n=112) and a test data set (n=28) for model development and validation, respectively. A generalized linear mixed model was fitted to the data using the marginal R 2 (m) and the Akaike information criterion to evaluate the models. The coefficient of determination of validation (R 2 (v)) for different models developed ranged between 0.18 and 0.41. Form the intake-related parameters, only inclusion of total DMI improved the prediction (R 2 (v)=0.58). In addition, in an attempt to further explore the relationships between MFA and CH4 emissions, the data set was split into three categories according to CH4 emissions: LOW (lowest 25% CH4 emissions); HIGH (highest 25% CH4 emissions); and MEDIUM (50% remaining observations). An ANOVA revealed that concentrations of several MFA differed for observations in HIGH compared with observations in LOW. Furthermore, the Gini coefficient was used to describe the MFA distribution for groups of MFA in each CH4 emission category. The relative distribution of the MFA, particularly of the odd- and branched-chain fatty acids and mono-unsaturated fatty acids of observations in category HIGH differed from those in the other categories. Finally, in an attempt to validate the potential of MFA to identify cases of high or low emissions, the observations were re-classified into HIGH, MEDIUM and LOW according to the proportion of each individual MFA. The proportion of observations correctly classified were recorded. This was done for each individual MFA and for the calculated Gini coefficients, finding that a maximum of 67% of observations were correctly classified as HIGH CH4 (trans-12 C18:1) and a maximum of 58% of observations correctly classified as LOW CH4 (cis-9 C17:1). Gini coefficients did not improve this classification. These results suggest that MFA are not yet reliable predictors of specific amounts of CH4 emitted by a cow, while holding a modest potential to differentiate cases of high or low emissions.
The aim of this study was to evaluate the dose response on in vitro methane (CH) production of PUFA to which the inoculum donor animals had been exposed early in life. Sixteen Holstein calves (160 ± ...3 and 365 ± 2 kg BW) at 6 and 12 mo of age were used as inoculum donors. Half of the calves were given increasing amounts of extruded linseed from birth (22 g/d) until 4 mo of age (578 g/d) first mixed with milk and then included in their concentrate. Linseed oil (LSO) was supplemented in vitro at 5 different doses (0, 0.6, 1.2, 2.4, and 4.8 mg/mL). Supplementation of LSO in the rumen inocula at both ages linearly decreased ( < 0.05) the in vitro CH production. Total in vitro VFA production was not affected by LSO supplementation. Inhibition of CH was smaller when using the rumen inoculum from calves that had received a similar treatment early in life ( < 0.05). Differences in response to in vitro supplementation of a type of fatty acids similar to those applied during early life suggest some "changes" in the functioning of the rumen microbial community.
Using behavioural indicators of thermal discomfort, that is, shade seeking, panting scores (PS) and respiration rate (RR), we evaluated the effect of hot summer conditions and shade, for a herd of ...adult Holstein dairy cows and a herd of Belgian Blue beef cows kept on pasture in a temperate area (Belgium). During the summer of 2012, both herds were kept on pasture without access to shade (NS). During the summers of 2011 and 2013 each herd was divided into one group with (S) and one without (NS) access to shade. Shade was provided by young trees with shade cloth (80% reduction in solar radiation) hung between them. For S cows, we investigated how shade use was related to hot conditions as quantified by six climatic indices. The heat load index (HLI), which incorporates air temperature and humidity, solar radiation and wind speed, was the best predictor of the six indices tested. In 2011, there was a relatively high threshold for use of shade. When HLI=90, shade use probability reached 17% for dairy cows and 27% for beef cows. In 2013, however, at HLI=90, shade use probability reached 48% for dairy cows and 41% for beef cows. For animals from the NS treatment we determined the effect of hot summer conditions on RR and PS (with 0=no panting and 4.5=extreme panting). In both types of cattle, an increase in black globe temperature was the best predictor for increasing RR and PS. Furthermore, we determined how the effect of hot summer conditions on RR and PS was affected by the use of shade. Under hot conditions (black globe temperature ⩾30°C), >50% of the animals under shade retained normal PS and RR (PS<1 and RR<90 breaths per minute), whereas normal RR and PS were significantly less prevalent for animals outside shade. Our findings suggest that, even in temperate summers, heat can induce thermal discomfort in cattle, as evidenced by increases in shade use, RR and PS, and that shade increases thermal comfort.
Understanding the rumen microbial ecosystem requires the identification of factors that influence the community structure, such as nutrition, physiological condition of the host and host–microbiome ...interactions. The objective of the current study was to describe the rumen microbial communities before, during and after a complete rumen content transfer. The rumen contents of one donor cow were removed completely and used as inoculum for the emptied rumen of the donor itself and three acceptor cows under identical physiological and nutritional conditions. Temporal changes in microbiome composition and rumen function were analysed for each of four cows over a period of 6 weeks. Shortly after transfer, the cows showed different responses to perturbation of their rumen content. Feed intake depression in the first 2 weeks after transfer resulted in short-term changes in milk production, methane emission, fatty acid composition and rumen bacterial community composition. These effects were more pronounced in two cows, whose microbiome composition showed reduced diversity. The fermentation metrics and microbiome diversity of the other two cows were not affected. Their rumen bacterial community initially resembled the composition of the donor but evolved to a new community profile that resembled neither the donor nor their original composition. Descriptive data presented in the current paper show that the rumen bacterial community composition can quickly recover from a reduction in microbiome diversity after a severe perturbation. In contrast to the bacteria, methanogenic communities were more stable over time and unaffected by stress or host effects.
Lameness research in cattle focuses on daily or weekly variation of several typical gait features, i.e. stride time, stride length or arching of the back. In human gait research however, the ...variation of typical gait characteristics within one measurement is taken into account and serves as a sensitive and clinically relevant parameter in the evolution of diseases and the response to therapeutic interventions. In this paper the utility of such within measurement variation of gait variables was investigated for lameness research in cattle by comparing variables between lame cows, cows that are scored mildly lame by a trained observer but not yet noticed lame by the farmer, and cows that were scored severely lame and were noticed lame by the farmer in two case-control studies. Additionally, the repeatability of all variables was tested using eight non-lame cows.
The measurements with the GAITWISE were found to be highly repeatable and are therefore suited for cow gait characterization. The new set of inconsistency variables was able to distinguish between non-lame and becoming lame (mildly lame but not yet noticed by the farmer) cows. These results suggest the usefulness of such variables of stride-to-stride-fluctuation for early detection of lameness. Whether they are more sensitive for early lameness detection compared to the more conventionally used averaged gait variables should be confirmed in longitudinal studies with non-lame cows and cows that develop lameness. All cows that were selected in the case control studies were mildly or severely lame in the left hind leg. Cows that were severely lame on their left hind leg put less force and take shorter steps with that sore leg increasing stance times on the right side. In addition, their stride to stride fluctuations of ‘stance times on the left front leg’ and ‘step length between left hind and right front leg’ significantly increase for the cows that were mildly lame but not yet noticed lame by the farmer. This strong relationship between the localization of the lameness and the significantly changed variables, suggest that the variables measured by the GAITWISE are promising in defining which leg is developing lameness in cows.
Dietary branched‐chain amino acid and tryptophan concentrations have been associated with effects on daily feed intake; this study is an extension of that research. We evaluated eight dietary ...treatments in a Latin square cross‐over design with 32 female piglets during 8 weeks (9.9 ± 0.6 kg to 44.9 ± 2.9 kg, mean ± SD). Treatments differed in dietary standardized ileal digestible leucine (10.8 and 21.3 g/kg), valine (7.0 and 7.8 g/kg), isoleucine (6.0 or 7.3 g/kg) and tryptophan (2.0 and 2.5 g/kg) content. A longitudinal model was fitted with the level of valine, leucine, isoleucine, tryptophan and the interactions leucine × tryptophan, valine × leucine, isoleucine × tryptophan as fixed effects. Increasing the dietary leucine content decreased feed intake (−169 g/day) and daily gain (−168 g/day) of the pigs and impaired the feed conversion ratio (+0.49 g/g) (p < 0.01 for all parameters). Adding valine to the high leucine diet counteracted the feed intake reduction partially, while effects on daily gain and feed conversion ratio were largely counteracted by adding extra valine. The positive effect on feed conversion ratio diminished over time (p = 0.001 for age × valine). Adding extra tryptophan to the high leucine diet tended to negatively affect daily gain (p = 0.081) and feed conversion ratio (p = 0.074). Adding extra dietary isoleucine together with extra valine did not further counteract the negative effects of excess dietary leucine. The present results confirmed that, with excess leucine, extra valine benefits performance. Further adding extra tryptophan or isoleucine did not improve performances.
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