@article {3672,
	title = {Modelling winter feeding practices with fodder beet in growing and dry dairy cattle},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {82},
	year = {2022},
	month = {01/2022},
	pages = {39-44},
	address = {Online},
	abstract = {<p>The objective of this study was to use the Large Ruminant Nutrition System simulation (LRNS) model to evaluate inclusion of different proportions of fodder beet (FB) with several feed supplements to determine if these dietary combinations meet the nutrient requirements of dry cows and growing one-year-old (R1) heifers over winter. The LRNS simulations demonstrated deficiencies in Ca and P when diets contained 60 and 80\% of FB, especially for dry cows up to 21 days before calving and in R1 heifers. When FB comprised 60-80\% of the diet of R1 heifers, there was insufficient metabolisable protein to support maximum average daily gain and insufficient physically effective neutral detergent fibre (peNDF) in diets containing over 60\% FB. Diets containing more than 40\% FB had a negative rumen degraded protein balance (RDPB) and an excess non-fibre carbohydrate (NFC) concentration. Recommendations based on this modelling are for a maximum of 60\% FB in diets and forage supplements must provide sufficient crude protein (CP) as well as supplementation of Ca for R1 heifers and dry cows up to 21 days before calving and P for both dry cows and R1 heifers.</p>
},
	issn = {1176-5283},
	author = {Jonker A and Dalley DE and Woods RR and Dynes RA and Pacheco D and Khan MA and Edwards JP and Hammond KJ}
}
@article {3672,
	title = {Can GreenFeed automated emissions monitoring systems measure methane output from young red deer grazing pasture?},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {93-98},
	address = {Online},
	abstract = {and validation of methane-mitigation strategies for farmed deer requires a technology that can be deployed under grazing conditions. The GreenFeed automated emissions monitoring system (GAEM) integrated with an automated concentrate feeder has been successfully used to determine methane output from cattle but has not been tested with deer. The objective of this study was to evaluate large and small ruminant GAEM units with rising-yearling red deer, to determine if they would access the feed lure, and remain for sufficient duration in the hood of the unit to collect representative measurements of methane outputs. Groups of 14 mixed-sex red deer were used in three trials during spring of 2020. In each trial, approximately a third of individuals accessed the GAEM units after being habituated to the lucerne pellet lure, more than 85\% of visits were < 2 min. With further refinement of deer-training protocols and configuration of the GAEM, pasture-based methane outputs should be able to be measured for a proportion of any mob with access to the unit.

Keywords: GreenFeed; red deer; methane},
	issn = {1176-5283},
	author = {Bennett CP and Ward JF and Jonker A}
}
@article {3672,
	title = {Evaluation of existing equations to rank methane yields of sheep fed a range of fresh forages},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {159-163},
	address = {Online},
	abstract = {The objective of the current study was to evaluate the performance of published equations to predict CH4 yield (g CH4/kg dry matter intake; DMI) in NZ sheep fed a range of fresh forages. A database with 182 NZ sheep CH4-yield treatment means was used to validate 17 published CH4-yield prediction equations. The CH4-yield predictions were evaluated using the square root of mean-square prediction error (RMSPE) and Lin{\textquoteright}s concordance correlation coefficient (CCC). The three prediction equations with the smallest error (<22\% of RMSPE) and the only ones with moderate CCC with observed CH4 yield were all based on data from animals fed forage only. These three models predicted CH4 yield based on DMI plus dietary neutral detergent fibre, and animal body weight, feed crude protein, or feed organic matter digestibility; and they performed better than the DMI only equations that are commonly used in national greenhouse gas inventory models and on-farm accounting models
.
Keywords: Meta-analysis; enteric methane; model validation; fodder crops},
	issn = {1176-5283},
	author = {Jonker A and Eug{\`e}ne M and de Klien C and Pacheco D and Vibart R}
}
@article {3672,
	title = {Sheep divergently selected for methane yield showed differences in meat fatty acid composition},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {173-178},
	address = {Online},
	abstract = {The purpose of this work was to investigate whether 18-month-old rams from the methane selection lines differed in their levels of soft tissue depth over the 12th rib (GR, as a proxy of carcass fatness) intramuscular fat (IMF), and the fatty acid composition of IMF. The rumen is the site of microbial biohydrogenation of consumed plant fatty acids and synthesis of unique microbial body fatty acids. It is known that there are differences in the microbiome and fermentation characteristics of sheep selected for and against methane production (methane selection lines). When comparing the high and low lines several differences were found. Rams from low-methane-yield-selection lines tended to have lower GR (P<0.06) than those from high line rams, but there was no evidence for a difference in levels of IMF between the lines (P=0.77). There were, however, many significant differences in the fatty acid composition (as a \% of total fatty acids) of the IMF between the lines. The IMF from the low-methane-yield line had a significantly (P<0.05) higher proportion of branched-chain fatty acids, and fatty acids that are associated with the early stages of the biohydrogenation pathways in the rumen, specifically conjugated linoleic acid (CLA) and C18:1 t11 but with less C18:0 stearic acid (the end product of biohydrogenation) and a significantly higher proportion of C16:1 t9 which is produced through β-oxidation of C18:1 t11. These results provide insight into how differences in sheep from the methane-yield selection line may influence the fatty acid composition of their fat.


Keywords: Methane; sheep; intramuscular fat; fatty acid composition},
	issn = {1176-5283},
	author = {PL Johnson and Agnew M and Jonker A and Hickey SM and McEwan JC and Bryson B and Dodds KG and Rowe SJ}
}
@article {3672,
	title = {Volatile fatty acids (VFA) in rumen samples collected pre-feeding had a stronger relationship with methane emissions in lambs fed graded levels of forage rape than VFAs in post-feeding samples},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {168-172},
	address = {Online},
	abstract = {To investigate the effect of farm system, and cow selection for milk urea nitrogen (MUN), on milk yield and milk composition,
a farmlet study was carried out between October 2018 and May 2019 in Lincoln, Canterbury. A farm system with a low stocking
rate and low N fertiliser input (LSR, 2.9 cows/ha) sown with a conventional ryegrass clover and plantain diverse pastures was
compared with a farm system with a moderate stocking rate and moderate N fertiliser (MSR, 3.9 cows/ha) using conventional
ryegrass and white clover pastures and supplementing 3 kg DM/cow/d as crushed barley grain. Each farmlet had total herd size of
40 mixed-age HF x J spring-calving dairy cows which included six cows selected solely for a high MUN or a low MUN. There was
no effect of farm system on milk fat, protein or lactose content but MUN was lower in LSR compared with MSR. Milk production
was also lower for LSR (466 vs 429{\textpm}12.4 kg MS/cow/ha, P<0.05), owing to poorer quality diet in mid lactation. Cows selected
for low MUN tended to produce less milk compared with high MUN cows (4478 vs 3987{\textpm}174 kg/cow, P<0.10) though this was
partially offset by increased protein content in milk of low MUN cows. Farm system and animal selection for MUN have a greater
impact on milk yield than on milk composition.

Keywords: Plantago lanceolata; somatic cell count; multi-species pastures;},
	issn = {1176-5283},
	author = {Della Rosa MM and Janssen PH and Reid P and Sandoval E and Luo D and Pacheco D and Jonker A}
}
@article {3672,
	title = {BRIEF COMMUNICATION: Effect of a fodder beet or lucerne-chaff-based diet on triplet-bearing ewe live weight, body condition score and lamb birth weight},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {168-170},
	address = {Palmerston North},
	abstract = {The objective was to determine whether a fodder-beet based diet (FB) balanced for crude protein, vitamins and minerals could support similar ewe live weight (LW), body condition score (BCS) and lamb birth weight compared to a lucerne-based diet. Triplet-bearing ewes (60-70 days gestation) were randomly allocated to a lucerne-based (65\% of dry matter [DM] n=12) or FB-based (56\% FB bulb; n=16) diet. Lambs were weighed two hours after birth. Ewe LW (P=0.970) and BCS (P=0.165) did not differ between treatments and there was no diet-by-day gestational age (dGA) interaction. A diet-by-dGA interaction was observed for DM intake (P=0.003) where FB-fed ewes consumed less than control ewes with advancing gestation. A diet-by-sex interaction was evident for lamb birth weight (P=0.026) where female lambs from FB-fed ewes were heavier than female lambs from control-fed ewes, with no difference between males. These results indicate that supplementing a FB-based diet with additional protein, fibre and minerals can maintain triplet-bearing ewe BCS and LW and improve female lamb birth weight compared to those born to control ewes.},
	issn = {1176-5283},
	author = {Knol FW and Erichsen C and Jonker A and Sandoval E and Pacheco D and Hea SY and McCoard SA}
}
@article {3672,
	title = {Circadian variation in methane emissions by cattle and correlation with level and composition of ryegrass-based pasture eaten},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {61-64},
	address = {Palmerston North},
	abstract = {The objective of the study was to determine the circadian variation in CH4 emission from cattle fed ryegrass-based pasture offered in two meals a day and identify factors that affect this circadian variation. Methane emission data (expressed as g/d) of 15 respiration chamber trials with growing beef cattle (six trials) or non-lactating (three trials) and lactating (six  trials) dairy cows was analysed. Minimum CH4 production rate, measured approximately every 3 minutes, in the 24 h day, among the 15 trials ranged from 51 g/d to 217 g/d, and maximum CH4 production rate ranged from 152 g/d to 471 g/d. The ratio of maximum to minimum CH4 production rate, indicating absolute circadian variation, among the 15 trials, ranged from 1.8-fold to 4.4-fold. This ratio correlated negatively with feeding level (r =- 0.57; P < 0.05) and within the growing and non-lactating cattle dataset, the ratio also correlated negatively with forage neutral and acid detergent fibre concentration (r = -0.74; P < 0.10) and positively with crude protein concentration (r = 0.77; P < 0.10). In summary, the magnitude of circadian variation in CH4 emissions decreased with increasing feeding level over the whole dataset and also with changing pasture composition within the growing and non-lactating animal dataset. },
	issn = {1176-5283},
	author = {Biswas AA and Jonker A}
}
@conference {3672,
	title = {A comparison of faecal sample collection times for estimating faecal output and total tract digestibility using inert markers in sheep offered three ryegrass cultivars at two allowances},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {43-48},
	address = {Rotorua},
	abstract = {The objective of this study was to compare different faecal sampling regimes (collected in the morning (am) or the afternoon (pm), or the weighted mean of both times) for determining the concentrations of faecal markers (the natural odd-chain n-alkanes (C27 
{\textendash} C35) contained in feed, the dosed (once daily in the morning) synthetic n-alkanes (C32 and C36) and titanium dioxide (TiO2)) and their accuracy for estimating dry matter digestibility (DMD) and faecal dry matter (DM) output from wethers (n = 30) fed cut ryegrasses.  The concordance correlation coefficient (CCC) with measured faecal DM output was strong (CCC = 0.8) for faecal DM output predicted from the mean concentration of C32 in morning and afternoon faeces (am+pm), moderate (CCC = 0.6-0.7) when predicted from TiO2 am and am+pm, and weak when predicted from C36. The DMD predicted by C27 and C33 at either collection time, and by C29 and C31 for samples collected in the pm, were similar to measured DMD. The estimated DMD based on faecal C35 had a negligible CCC with measured DMD (CCC<0.1), while other natural n-alkanes had a low to moderate CCC (0.3-0.6) with measured DMD, especially for the samples collected pm and am+pm. For applications with grazing animals, where marker dosing and faecal sampling is often restricted to once daily in the morning for practical reasons, TiO2 was the most accurate marker to estimate faecal DM output and C31 or C33 were the most accurate and precise markers to estimate DMD.},
	issn = {1176-5283},
	author = {Jonker A and Cosgrove GP}
}
@conference {3672,
	title = {Nitrogen partitioning in sheep offered three perennial ryegrass cultivars at two allowances in spring and autumn},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {74-78},
	address = {Dunedin},
	abstract = { },
	issn = {1176-5283},
	author = {Jonker A and Cheng L and Edwards GR and Molano G and Taylor PS and Sonoval E and Cosgrove GP}
}
@conference {3678,
	title = {BRIEF COMMUNICATION: Methane emissions by sheep offered high sugar or conventional perennial ryegrass at two allowances},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {145-147},
	address = {Napier},
	abstract = {Perennial ryegrass (Lolium perenne L.) with a higher concentration of water-soluble carbohydrates (WSC) has been bred by plant breeders (Humphreys 1989). Ryegrass with a higher WSC can potentially alter rumen microbial fermentation, synchrony of energy and protein in the rumen, total energy supply to the animal and consequently productivity (Edwards et al. 2007). Methane originates mainly from rumen fermentation and is the main greenhouse-gas produced by New Zealand (NZ) agriculture (MfE 2013). The higher concentration of WSC in high sugar ryegrass (HSG) can change rumen fermentation patterns (Lee et al. 2003) and may consequently affect methane emissions. Methane emissions are largely driven by dry matter intake (DMI) (Hammond et al. 2013) and methane mitigation strategies are often more effective at a high DMI (Moe \& Tyrrell 1979). However, a true methane mitigation strategy should be effective at any DMI level.

The objective of this study was to determine methane emissions from sheep fed freshly cut diploid HSG, conventional diploid ryegrass (CRG) and tetraploid ryegrass (TRG) offered at two levels of metabolisable energy for maintenance (MEm).},
	issn = {1176-5283},
	author = {Jonker A and Molano G and Sandoval E and Taylor PS and Antwi C and Cosgrove GP}
}
@conference {89254,
	title = {In vitro ruminal fermentation and methane production from maize silage mixed with high or low quality ryegrass},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {202-204},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p class="rtejustify">Methane is the main greenhouse-gas produced by New Zealand agriculture (Ministry for the Environment 2011). The methane loss from ruminants generally ranges from 4.5\% to 9\% of gross energy intake (Hammond et al. 2009). This indicates there is scope for lowering methane production. Replacing pasture forage with maize silage could decrease methane emission by altering fermentation patterns and by reducing rumen pH or ruminal retention time with the addition of starch to the diet (Beauchemin et al. 2008). However, Waugh et al. (2005) found that methane yield (g/kg DM intake) increased when pasture forage was substituted with up to 35\% maize silage in dairy cows fed at similar intakes. Other literature suggests that methane yield in cattle responds in a quadratic manner when pasture forage is substituted with maize silage or grain (Blaxter \&amp; Wainman 1964; Arndt et al. 2010; Hassanat et al. 2012). This effect is associated with pasture forage quality (Kirkpatrick et al. 1997).</p>
},
	issn = {1176-5283},
	author = {Jonker A and Pacheco D}
}
