Repeatability of enteric methane determinations from cattle using either the SF6 tracer technique or the GreenFeed system

2016 ◽  
Vol 56 (3) ◽  
pp. 238 ◽  
Author(s):  
M. Arbre ◽  
Y. Rochette ◽  
J. Guyader ◽  
C. Lascoux ◽  
L. M. Gómez ◽  
...  

The SF6 tracer technique (SF6) and GreenFeed system (GF) are two methods for measuring enteric methane (CH4) emissions from cattle. Both methods estimate individual daily CH4 emissions from expired gas samples collected either continuously over 24 h in a canister (SF6) or several times a day during short-term periods (3–8 min) when cattle visit an automated head chamber (GF). The objective of this work was to study repeatability (R) of each method according to duration of measurement period as an indicator of their precision. The R of CH4 measurements was evaluated in two different trials using cows. For Experiment 1, the SF6 technique was used for 20 days in six non-lactating dairy cows fed a hay-based diet; for Experiment 2, the GF system was used for 91 days in seven lactating dairy cows fed a maize silage-based diet. The CH4 data were grouped by periods of 1–10 days (SF6) and 1–45 days (GF). The CH4 emissions averaged 23.6 ± 3.9 g/kg dry matter intake (DMI) for the SF6 and 17.4 ± 3.3 g/kg DMI for the GF on the measurement period. To achieve an R value of 0.70 for CH4 emissions (g/kg DMI), 3-day periods were necessary for SF6 and 17-day periods for GF. The R did not increase after 4-day periods for SF6 (R = 0.73), but increased for GF until 45-day periods (R = 0.90). In our experimental conditions and R = 0.70, the total number of cows necessary to detect a significant difference in CH4 emissions (g/kg DMI) between two treatments (e.g. diet) was similar for SF6 and GF.

2016 ◽  
Vol 56 (3) ◽  
pp. 312 ◽  
Author(s):  
M. Niu ◽  
J. A. D. R. N. Appuhamy ◽  
A. B. Leytem ◽  
R. S. Dungan ◽  
E. Kebreab

The study aimed to examine, simultaneously, the effects of changing dietary forage and crude protein (CP) contents on enteric methane (CH4) emissions and nitrogen (N) excretion from lactating dairy cows. Twelve post-peak lactating Holstein cows (157 ± 31 days postpartum; mean ± s.d.) were randomly assigned to four treatments from a 2 × 2 factorial arrangement of two dietary forage levels [37.4% (LF) vs 53.3% (HF) of DM] and two dietary CP levels [15.2% (LP) vs 18.5% (HP) of DM] in a 4 × 4 Latin square design with four 18-day periods. Alfalfa hay was the sole source of dietary forage. Cows were fed ad libitum and milked twice daily. During the first 14 days, cows were housed in a free-stall barn, where enteric CH4 emissions were measured using the GreenFeed system from Days 8 to 14 in each period. Cows were then moved to metabolic cages, where faeces and urine output (kg/cow.day) were measured by total collection from Days 16 to 18 of each period. No dietary forage by CP interactions were detected for DM intake, milk production, enteric CH4 emissions, or N excretions. There was a tendency for DM intake to increase 0.6 kg/day in cows fed LF (P = 0.06). Milk production increased 2.1 kg/day in LF compared with HF (P < 0.01). Milk fat content decreased in cows fed LF compared with HF (1.07 vs 1.17 kg/day; P < 0.01). Milk contents of true protein, lactose and solid non-fat were greater in cows fed LF (P < 0.01). No difference in DM intake, milk yield and milk contents of true protein, lactose and solid non-fat was found between cows fed HP or LP. However, milk fat content increased 0.16 kg/day in cows fed HP (P < 0.05). Enteric CH4 emissions, and CH4 per unit of DM intake, energy-corrected milk, total digested organic matter and neutral detergent fibre were not affected by dietary CP, but decreased by LF compared with HF (P < 0.01). Milk true protein N was not affected by dietary CP content but was higher for LF compared with HF. Dietary N partitioned to milk true protein was greater in cows fed LF compared with HF (29.4% vs 26.7%; P < 0.01), also greater in cows fed LP compared with HP (30.8% vs 25.2%; P < 0.01). Dietary N partitioned to urinary N excretion was greater in cows fed HP compared with LP (39.5% vs 29.6%; P < 0.01) but was not affected by dietary CP content. Dietary N partitioned to faeces was not affected by dietary CP but increased in cows fed LP compared with HP (34.2% vs 27.8%; P < 0.01). Total N excretion (urinary plus faecal) as proportion to N intake did not differ between HP and LP, but tended to be lower in cows fed LF compared with the HF diet (64.2% vs 67.9%; P = 0.09). Both milk urea N (P < 0.01) and blood urea N (P < 0.01) declined with decreasing dietary CP or forage contents. Based on purine derivative analysis, there was a tendency for interaction between dietary CP and forage content on microbial protein synthesis (P < 0.09). Rumen microbial protein synthesis tended to be lower for high forage and low protein treatments. Increasing dietary forage contents resulted in greater CH4 emission (g/kg of energy-corrected milk) and manure N excretion (g/kg of energy-corrected milk) intensities of lactating dairy cows. Cows receiving reduced CP diets had low manure N outputs and improved milk true protein production efficiencies, regardless of dietary forage content.


2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 294-295
Author(s):  
K. A. Juntwait ◽  
A. F. Brito ◽  
K. S. O'Connor ◽  
R. G. Smith ◽  
K. M. Aragona ◽  
...  

2008 ◽  
Vol 48 (2) ◽  
pp. 124 ◽  
Author(s):  
J. B. Vlaming ◽  
N. Lopez-Villalobos ◽  
I. M. Brookes ◽  
S. O. Hoskin ◽  
H. Clark

Several studies on methane (CH4) emissions have focussed on selecting high and low CH4-emitting animals. One challenge faced by this work is the lack of consistency, or repeatability, in animal rankings over time. Repeatability for individual animals over time needs to be high to reliably detect high and low CH4-emitting animals. A possible explanation for the lack of repeatability is a relatively high within-animal variation in daily CH4 emissions, meaning that animals could then change their ranking when compared at different points in time. An experiment was undertaken with four non-lactating dairy cattle to assess the within- and between-animal variation in CH4 emissions over time when measured using the sulfur hexafluoride (SF6) tracer technique. Two contrasting diets were fed to the cattle at maintenance energy levels: lucerne silage (diet 1) and a cereal + lucerne + straw mixed ration diet (diet 2). Daily CH4 measurements were undertaken for 23 days on diet 1 and 30 days on diet 2. There was a significant (P < 0.001) difference between diet 1 and diet 2 in daily CH4 production, with mean (±s.e.) production of 124.3 (11.1) g CH4/day from diet 1 and 169.8 (±11.0) g CH4/day from diet 2. Lower CH4 yield (g CH4/kg dry matter intake) was recorded on diet 1 (22.8 ± 2.0) than diet 2 (32.0 ± 2.0). Cows differed significantly (P < 0.05) from one another in daily CH4 yield (diet 1: cow 1 = 19.4 ± 0.6, cow 2 = 22.2 ± 0.8, cow 3 = 23.2 ± 0.7, cow 4 = 25.4 ± 0.6; diet 2: cow 1 = 26.0 ± 0.7, cow 2 = 36.4 ± 0.7, cow 3 = 29.3 ± 0.7, cow 4 = 36.6 ± 0.7). Variances for daily CH4 yield were smaller for diet 1 (within animal = 6.91, between animals = 6.23) than for diet 2 (within animal = 10.09, between animals = 27.79). Estimates of repeatability (variation between animals/total variation) for daily CH4 yield were 47 and 73% in diet 1 and 2, respectively. Coefficients of variation in average daily CH4 emissions in this experiment ranged from 8 to 18% despite the fact that each animal received the same quantity and quality of feed each day. While further research is required, the high within-animal variability in CH4 emissions measured using the SF6 tracer technique may explain why there has been difficulty in obtaining consistent rankings in CH4 yields when animals are measured on multiple occasions. The results also suggest that the SF6 tracer technique may exaggerate apparent between animal differences in CH4 emissions.


2017 ◽  
Vol 57 (7) ◽  
pp. 1445 ◽  
Author(s):  
Arjan Jonker ◽  
David Scobie ◽  
Robyn Dynes ◽  
Grant Edwards ◽  
Cecile De Klein ◽  
...  

Fodder beet (Beta vulgaris L.) has a very high readily fermentable carbohydrate concentration, which could affect rumen fermentation and reduce enteric methane (CH4) emissions. The objective of the current study was to estimate CH4 emissions from dry dairy cows grazing either fodder beet supplemented with perennial ryegrass (Lolium perenne L.)-dominated pasture silage (6 kg DM/cow/day; FB+Sil) or forage kale (Brassica oleracea L.) supplemented with barley (Hordeum vulgare L.) straw (3 kg DM/cow/day; kale+Str; dry cows, Experiment 1), and from dairy cows in early lactation grazing perennial ryegrass-dominated pasture alone (pasture) or supplemented with fodder beet bulbs (3 kg DM/cow/day; past+FB; lactating cows; Experiment 2). Methane measurements were performed using GreenFeed units (C-Lock Inc., Rapid City, SD, USA) for 40 days in August–September 2015 (Experiment 1) and for 22 days in November–December 2015 (Experiment 2), from 45 and 31 Holstein–Friesian × Jersey dairy cows in Experiments 1 and 2, respectively. Dry cows grazing FB+Sil in Experiment 1 produced 18% less CH4 (g/day) and had 28% lower CH4 yield (g/kg DM intake; P < 0.001) than did cows grazing kale+Str. Lactating cows grazing past+FB in Experiment 2 produced 18% less CH4 and had 16% lower CH4 intensity (g/kg fat and protein-corrected milk production; P < 0.01) than did cows grazing pasture alone, while milk production and composition were similar for the two groups. In conclusion, feeding fodder beet at ~50% and 20% of the diet of dry and lactating dairy cows in pastoral systems can mitigate CH4 emissions.


1994 ◽  
Vol 58 (2) ◽  
pp. 181-187 ◽  
Author(s):  
R. J. Dewhurst ◽  
C. H. Knight

AbstractTwenty lactating dairy cows were used to investigate the relationship between the site of milk storage in the udder and the short-term response to thrice-daily milking. Cisternal and alveolar milk volumes were measured 8 h after an ordinary morning milking by catheter drainage and machine milking with oxytocin respectively. The response to thrice-daily milking was assessed using a half-udder technique and the relative milk yields quotient (RMYQ). Over the first 7 days, both halves were milked twice daily (8/16 h intervals) and milk yields over the final 4 days of this period were higher for left fore/right hind (LF/RH) (12·4 (s.e. 0·85) kg/day) than for RF/LH (10·5 (s.e. 0·63) kg/day) which was milked after LF/RH throughout the experiment. Over the following week, LF/RH quarters were milked an additional time (8/8/8 h intervals) and yields over the final 4 days were increased (15•7 (s.e. 0·95) kg/day) compared with control quarters (9·8 (s.e. 0·73) kg/day). In a final 4-day period, animals were milked twice daily and half udder yields were 13·1 (s.e. 0·89) kg/day and 10•6 (s.e. 0·77) kg/day respectively. Differences between yields from the two halves of the udders were highly significant in all 3 weeks of the experiment (P < 0·001). Cistern milk yield as a proportion of total milk yield at 8 h (cistern proportion) averaged 0·170 (s.e. = 0·0275; range 0·020 to 0·334) and tended to be greater for multiparous (0·215, s.e. 0·0279) than for primiparous animals (0·118, s.e. 0·0437; P = 0·076). During the periods of twice-daily milking, the proportion of milk yielded from LF/RH quarters was not significantly related to cistern proportion (P = 0·70 and 0·43 for weeks 1 and 3 respectively). However the response to thrice-daily milking, assessed as RMYQ, was significantly related to cistern proportion both when changing up to, and down from, thrice-daily milking (P < 0·01). Animals with low cistern proportions showed larger responses to thrice-daily milking. There was a significant relationship (P < 0·05) between the responses on changing up to, and down from, thrice-daily milking. Primiparous animals tended to exhibit smaller declines on returning to twice-daily milking than multiparous animals with equivalent responses to thrice-daily milking.


Author(s):  
Jayaraj Neelima ◽  
Purushothaman Sajith ◽  
K. Ally ◽  
Ananth Deepa ◽  
Simon Shibu

An experiment was conducted on early lactating dairy cows to study the effect of rumen protected choline (RPC) and methionine (RPM) on milk yield and composition. Fifteen crossbred dairy cows in early lactation (within 10 days of calving) were selected and randomly allotted to any one of the following three dietary treatments, T1 (Control)- with compound feed mixture containing CP- 20% and TDN- 68% , T2- T1+20g RPM and 20g RPC, T3- with compound fed mixture containing CP- 17%, TDN- 68% + 20g RPM and 20g RPC. All the experimental animals were fed as per ICAR feeding standards (ICAR, 2013). Results revealed no significant difference (p>0.05) in milk yield and 4 per cent fat corrected milk (FCM) yield between the three treatment groups. Among the milk constituents, animals in T3 had significantly higher milk fat (p<0.05), SNF (p<0.05), protein (p<0.05) and total solids (p<0.01) compared to those in T1 and T2. Milk urea nitrogen levels did not differ significantly among the three treatments and were within the normal range. The study showed that milk composition could be effectively improved by supplementing feed with rumen protected forms of choline and methionine in combination at lower dietary protein level without any reduction in milk yield.


1997 ◽  
Vol 129 (4) ◽  
pp. 459-469 ◽  
Author(s):  
P. J. MOATE ◽  
T. CLARKE ◽  
L. H. DAVIS ◽  
R. H. LABY

Results are reported from three experiments conducted at the Dairy Research Institute, Ellinbank, Australia during 1992/93 which examined the composition and kinetics of the gas in the rumen headspace of lactating dairy cows grazing white clover/perennial ryegrass pastures. Before grazing, rumen headspace gas was composed of carbon dioxide 65%, methane 31% and nitrogen 4% whereas, after one hour of active grazing, the headspace gas was composed of carbon dioxide 76%, methane 22% and nitrogen 2%. The composition of headspace gas was not affected by antibloat capsules (which release 250 mg/day of monensin). The headspace gas from bloated cows contained slightly less (P<0·01) carbon dioxide and slightly more nitrogen than that from non-bloated cows.A novel technique which employs ethane as a tracer to measure rumen headspace volume and the kinetics of the rumen headspace gases is described. The tracer technique was used in two experiments in which the influence of grazing, antibloat capsules and bloat on the rumen headspace volume and the kinetics of the headspace gases were examined. It is concluded that our ethane tracer technique provides a simple and inexpensive way to estimate methane production by grazing ruminants.


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