Department of Agricultural Sciences

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https://hdl.handle.net/10182/34

The Department of Agricultural Sciences consists of animal science, plant science and farm management and agribusiness staff members.

The range of research conducted is quite extensive including: conversion of forests into pasture, alternative dryland pasture species, grain legume agronomy, sustainability in farming systems, nitrogen fixation and nitrogen cycling, shelter on dairy farms, economic viability of NZ farming systems, animal nutrition, immunology etc.

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Open Access
Variation in the exon 3–4 region of ovine KRT85 and its effect on wool traits
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-08-01) Chai, W; Zhou, Huitong; Gong, H; Wang, C; Hickford, Jonathan
α-keratins are structural proteins in the cortex of wool fibres and assemble in an organized fashion into keratin intermediate filaments. Variation in these keratin proteins affects the structure and characteristics of wool fibre, making keratin genes ideal candidates for the development of gene markers that describe variations in wool traits. A region of KRT85 spanning exon 3–4 (including the entire exon 3, intron 3, exon 4 and part of intron 4) was investigated. Two banding patterns defining two variant sequences (A and B) were observed in this region, and these were characterised by the presence of two single nucleotide polymorphisms. The effect of this variation in the exon 3–4 region of KRT85 on wool traits was investigated in 463 Merino × Southdown-cross lambs. The frequencies of these two variants in these sheep were 55.6% and 44.4%, respectively. Three different genotypes were observed with frequencies of 32.6%, 46.1% and 21.3% for AA, AB and BB, respectively. The presence of A was associated with an increase in greasy fleece weight and clean fleece weight, while the presence of B was associated with an increased wool prickle factor. These findings should be replicated in a broader range of sheep breeds to determine whether the associations are robust and to clarify whether the observed effects are attributable to breed differences or to gene effects themselves.
Open Access
Exploring variation in ovine KRTAP19-5 and its effect on fine wool fibre curvature in Chinese Tan sheep
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-08-01) Bai, L; Zhou, Huitong; Li, W; Tao, J; Hickford, Jonathan
Sheep’s wool is known to have unique biological, physical and chemical properties. The fibre primarily consists of proteins, but these have amino acid sequence variation, and at the phenotypic level wool fibre varies considerably. This can affect its utility and value. Unravelling the genetic factors that underpin the protein and phenotypic variability is crucial if we are to contemplate improving wool quality. Accordingly, this study investigates the high glycine and tyrosine content keratin-associated protein 19-5 gene (KRTAP19-5) in sheep. PCR-single strand confirmation polymorphism analysis, coupled with DNA sequencing of a region spanning whole coding sequence, revealed six sequence variants containing seven single nucleotide polymorphisms (SNPs). Five of the SNPs were located within the coding region, with four leading to amino acid changes if expressed. In 247 Chinese Tan sheep derived from 10 sire-lines, and renowned for their distinct ‘spring-like’ crimped wool at up to approximately 35 days after birth, one of the variants was found to be associated with decreased curvature of the fine wool fibres in the fleece. No associations were detected with other fibre traits or with variation in the heterotypic hair fibres of the Tan sheep. While these findings may be useful for developing gene markers to alter mean wool fibre curvature and improve sheep breeding, many other genes and environmental factors are known to contribute to variation in fibre traits.
Open Access
Integral health farming
(Nature Research, 2024-09-10) Gregorini, Pablo; Gordon, Iain J; Fleming, Anita; Morris, Richard; Romera, Alvaro; Judson, Glenn; Moorhead, Allister; Barnes, John; Eggers, James; Charters, Stuart; Davis, Shannon; O’Sullivan, Anna
Society is increasingly aware of the connection between the health of the land, of animals and of humans. Visions of ‘foodscapes’ and ‘healthscapes’ are eclipsing the conventional view of landscapes focussed solely on production. Livestock production farming systems must co-evolve with this thinking. Lincoln University has designed and is implementing the Integral Health Dairy Farm (IHDF) to test and communicate these new and transformational systems views. Its objective is to innovate, to demonstrate and to manage a tangible transition from current practices to a system designed to enhance health, from the ground up. This includes measured improvements in soil, plant, animal, human and community health. In this ‘comment’, we focus on applied scientific integration of the ‘One health approach’ into agricultural systems of livestock, presenting our initial design and prototyping processes, as well as how it continues as the project moves from the drawing board to implementation, benefiting from a growing network of supporters and collaborators.
Open Access
Effects of KRTAP20-1 gene variation on wool traits in Chinese Tan sheep
(MDPI, 2024-08) Bai, L; Zhou, Huitong; Tao, J; Hickford, Jonathan
Chinese Tan sheep lambs are recognised for having tight ‘spring-like’ curly wool when young, but this phenotype disappears with age. This wool consists of shorter, fine wool fibres (which are usually unmedullated) and heterotypic hair fibres (which are frequently medullated), which are referred to as ‘halo hair’. Both the wool and hair fibres consist of α-keratin proteins embedded in a keratin-associated protein (KAP) matrix. Of these KAPs, the KAP20-1 gene (designated KRTAP20-1) and its effect on four fibre traits (mean fibre curvature, mean fibre diameter, fibre diameter standard deviation, and coefficient of variation of fibre diameter) of Tan lambs was studied. Seven previously identified KRTAP20-1 variants (A, B, D, E, F, G, and H) of KRTAP20-1 were revealed, but the previously identified variant C was not present. Of the seven variants detected, only two (A and G) were common and present at frequencies greater than 5%, and the effect of these on the fibre traits of the finer wool fibres was assessed. It was found that variant G was associated with an increased mean fibre curvature in these wool fibres. This suggests that KRTAP20-1 might possibly be expressed differentially in the two fibre types, which may be of future value in breeding.
Open Access
Reductionist science in agriculture and horticulture
(Taylor & Francis, 2024) Hickford, Jonathan; Goldson, Stephen; Caradus, JR; Rowarth, JS
Science ensures that explanations and predictions about the biological and physical worlds are verifiable, while also providing an approach that enables improved understanding to develop and be permanently recorded. There are several terms in common usage that describe the approaches used in scientific research, but at the extremes, words such as ‘reductionism’ and ‘holism’ are now frequently encountered. While singular reductionism can result in key relationships and linkages being missed, holism appears to ignore the need to identify how confounding factors can affect the quality of understanding derived from complex systems. Here we suggest that science is not a simple dichotomy of reductionism versus holism. Instead, it comprises a more fluid and complex mission. However, within multidisciplinary agricultural and horticultural science one regularly finds words like ‘systems’, ‘integration’, and ‘unifying’. Reductionist science is certainly part of the pursuit of holistic solutions to problems, not least in transdisciplinary research.
Open Access
Notes for plant collections
(Lincoln College. Plant Science Department, 1984) Horn, Philippa Evelyn; Hill, G. D.
Students of Botany and Plant Sciences are often required to make collections of plants. These may be native plants, plants of agricultural or horticultural importance, or plants of botanical interest. Such collections are usually part of the practical requirement of the courses. They: (1) Give an aid to learning common native, crop, pasture and horticultural plants. (2) Give experience in the use of plant identification keys (3) Give a knowledge of how to prepare specimens for submission to a qualified botanists when the collector is unable to identify the plant. (4) Give an indication of the methods involved in building up of large reference collections. An herbarium is a collection of plants preserved for study. It is an aid to the identification of subsequent collections. To be useful specimens in plant collections must be carefully selected, properly prepared and accompanied by adequate data. Vascular plants (ferns, gymnosperms and flowering plants) are most easily preserved by pressing and mounting on card. Pressed specimens may be supplemented by drying and/or pickling material in a suitable liquid medium. e.g pine cones are impossible to press, but keep well in the dried form. Fleshy fruits are best pickled in a suitable liquid.
Open Access
Varying tolerance to diesel toxicity revealed by growth response evaluation of Petunia grandiflora shoot lines regenerated after diesel fuel treatment
(MDPI, 2024-09) Wante, SP; Leung, DWM; Alizadeh, Hossein
Continuous efforts are required to find ways to protect crop production against the toxicity of petroleum hydrocarbons, such as diesel, and contamination of soils. There is a need for identification of candidate plants that are tolerant to diesel toxicity that might also have the potential for remediation of diesel-contaminated soils. In this study, petunia, a popular ornamental plant and a model experimental plant in research on phytoremediation of environmental pollutants, was used to evaluate a novel method for rapidly assessing diesel toxicity based on the tolerance of shoots generated through in vitro plant cell culture selection. Petunia shoot lines (L1 to L4) regenerated from diesel-treated callus were compared with those from non-diesel-treated callus (control). Significant morphological differences were observed among the tested lines and control, notably with L1 and L4 showing superior growth. In particular, L4 exhibited remarkable adaptability, with increased root development and microbial counts in a diesel-contaminated potting mix, suggesting that the shoots exhibited enhanced tolerance to diesel exposure. Here, this rapid bioassay has been shown to effectively identify plants with varying levels of tolerance to diesel toxicity and could therefore assist accelerated selection of superior plants for phytoremediation. Further research is needed to understand the genetic and physiological mechanisms underlying tolerance traits, with potential applications beyond petunias to other environmentally significant plants.
Open Access
The role of composites in livestock production : Lincoln University Animal Industries Workshop 2003 : The proceedings of a workshop for farmers and advisors held 8-9 May Lincoln University, 13-14 May Telford Rural Polytechnic, 15-16 May Ruahine Club, Dannevirke
(Lincoln University. Animal and Food Sciences Division., 2003)
Papers delivered in the Animal Industries Workshop 2003.
Open Access
Evaluating the potential of double-muscled Angus sires to produce progeny from dairy cows to meet premium beef brand specifications
(MDPI, 2024-08) Mckimmie, C; Amirpour-Najafabadi, H; Alizadeh, Hossein; Hickford, Jonathan
In response to the increasing global demand for sustainable beef production, this review of the literature was undertaken to explore the possibility of using the progeny of cows in the pasture-based New Zealand dairy production system that are mainly of the Holstein–Friesian, Jersey, and Holstein–Friesian x Jersey-cross breeds, to produce beef that meets the standards demanded by the Certified Angus Beef® (CAB) standard. CAB is a United States of America (USA) benchmark for beef quality. Traditionally, the offspring of dairy breeds have not been suitable for producing high-quality beef due to their genetic makeup and physical characteristics. However, in the USA, breeding programmes have used genetic strategies to boost muscle meat yield in terminal-sire breeds like the Lim-Flex® and NuEra Genetics® T14 cattle lines. In these lines, selection has focused on enhancing muscling and other Angus traits, including ensuring the cattle are homozygous polled and black-coloured. The overall aim has been to alter the phenotypic characteristics of the offspring of dairy cows by terminal-sire crosses, so they resemble the phenotype of purebred Angus cattle and meet the CAB standard. The approach can involve using different alleles of the myostatin gene (MSTN) carried by the terminal Angus sires to increase carcass value from the dairy cow-derived male progeny (including the MSTN c.821(del11) allele or the myostatin protein p.F94L leucine-containing allele) to increase meat yield and eating characteristics. It is concluded that a targeted selection and mating strategy could provide another source of high-quality beef production, and one that also meets societal demands for better animal welfare and increased sustainability.
Restricted
An investigation of the effects of added sulphur and nitrogen to S-responsive and S-non-responsive soils from Canterbury on the digestibility and chemical composition of perennial ryegrass plants (Lolium perenne L.) : A thesis submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science (Hons) in the University of Canterbury
(Lincoln College, University of Canterbury, 1976)
Several recent studies (Stewart & Porter, 1969; Baker et al, 1973) on crop plants and grass forages have shown that responses on large nitrogen (N) fertiliser applications were often limited by a deficiency of sulphur ( S). An inadequate supply of S not only affects yields, but also the quality of the herbage produced. In view of this close relationship between N and S nutrition in plants, the present study was undertaken to examine the interaction of N and S fertilisation on the yield and composition of perennial ryegrass in a pot experiment. The present study therefore attempts to determine: 1. effects of N and S fertilisation on the top and root yields of the grass ; 2. the influence of N and S on the quality of the grass herbage - as reflected by the percentage digestibility, chemical composition of N and S fractions and the amino acid composition of these plants , and 3. the S nutrition status of the grass from information concerning the quantity of N and S in the herbage.
Open Access
Differences in root morphologies of contrasting wheat (Triticum aestivum) genotypes are robust of a drought treatment
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-01) Si, Z; Delhaize, E; Hendriks, Pieter-Willem; Li, X
We aimed to assess the effect of water deprivation on root traits and to establish if the wheat cultivars Spica and Maringa would be useful as parental germplasm for a genetic analysis of root traits. Plants were grown in two markedly different soils under well-watered and water-limited treatments in controlled environment growth cabinets. The drought treatment was imposed as a gradual depletion of water over 28 days as seedlings grew from a defined starting moisture content. The root traits analyzed included length, nodal root number, thickness and nodal root angle. The relative differences in traits between genotypes generally proved to be robust in terms of water treatment and soil type. Maringa had a shallower nodal root angle than Spica, which was driven by the nodal roots. By contrast, the seminal roots of Maringa were found to be similar to or even steeper than those of Spica. We conclude that the differences in root traits between Spica and Maringa were robust to the drought treatment and soil types. Phenotyping on well-watered soil is relevant for identifying traits potentially involved in conferring water use efficiency. Furthermore, Spica and Maringa are suitable parental germplasm for developing populations to determine the genetics of key root traits.
Open Access
Increased dietary protein to energy ratio in pre-weaning lambs increases average daily gain and cortical bone thickness in the tibia
(MDPI, 2022-12) Gibson, MJ; Adams, BR; Back, PJ; Dittmer, KE; Herath, G; Pain, SJ; Kenyon, PR; Morel, PCH; Blair, HT; Rogers, CW
The objective of this study was to examine if diets differing in crude protein (CP) to metabolizable energy (ME) ratio (CP:ME) pre-weaning altered peripheral quantitative computed tomography (pQCT) measures of bone mass and strength in lambs. The left hind leg of lambs were available at the completion of a trial designed to examine the effect that altering the CP:ME ratio in milk replacer had on growth and body composition of pre-weaned lambs reared artificially. Treatments consisted of either normal commercial milk replacer (CMR, n = 10) containing 240 g/kg CP and 21.89 MJ/kg ME, high protein milk replacer (HPM, n = 9) containing CMR with additional milk protein concentrate to reach 478.7 g/kg CP and 19.15 MJ/kg ME or a mix of normal milk replacer and milk protein concentrate adjusted twice-weekly to match optimal CP:ME requirements (MB, n = 8) based on maintenance plus 300 g/d liveweight gain. At 22 kg live weight, lambs were euthanized and the tibia including the surrounding muscle was collected and scanned using pQCT at the mid-diaphysis. Lambs on the HPM and MB diets had a greater average daily gain (p < 0.01). There were limited differences in bone morphology and muscle mass, though notably the higher protein diets (MB and HPM) were associated with greater cortical thickness (p < 0.05) and, therefore, potentially greater peak bone mass at maturity This finding demonstrates that pre-weaning diets, and the protein content in particular, may influence the developmental potential of long bones and attainment of peak bone mass at maturity.
Open Access
Behavioural response to gastrointestinal parasites of yearling dairy calves at pasture
(Taylor & Francis, 2024-05-28) Bates, AJ; Fan, B; Greer, Andrew; Bryant, Racheal; Doughty, A
Aims: To investigate the association between gastrointestinal parasites (GIP) and animal behaviour in dairy calves under New Zealand pastoral conditions, using animal-mounted, accelerometer-based sensors. Methods: Thirty-six, 5–6-month-old, Friesian-Jersey, heifer calves fitted with animal activity sensors to track behaviour were randomly allocated to one of two treatment groups. Half the animals were challenged with an oral dose of 20,000 larvae of Ostertagia ostertagi and Cooperia oncophera once a week for 3 weeks and half were unchallenged. Five weeks after the last dose, seven infected and nine uninfected animals were treated with an oral anthelmintic (AHC) and data collected for a further week. Accelerometer data were classified into minutes per day eating, ruminating, in moderate–high activity or in low activity. Live weight and faecal egg counts (FEC) were recorded weekly over the study period. All animals co-grazed a newly sown pasture not previously grazed by ruminants and were moved every week to fresh grazing. Treatment status was blinded to those managing the animals which were otherwise treated identically. Results: Complete behavioural records were available from 30/36 calves, (13 challenged and 17 unchallenged). Before treatment with AHC, FEC increased in infected and un-treated calves over the study, while uninfected animals maintained a near zero FEC. There was no difference in live weight gain between the two groups over the study period. Bayesian, multinomial regression predicted differences in animal behaviour between infected and uninfected animals that were not treated with AHC over the 7 weeks following initial infection. Parasitised calves not treated with AHC were less active and spent up to 6 (95% highest density interval (HDI) = 1–11) minutes/day less in low level activity and up to 15 (95% HDI = 7–20) minutes/day less in moderate to high level activity. They ruminated up to 9 (95% HDI = 2–15) minutes/day more and ate up to 10 (95% HDI = 2–19) minutes/day more than control calves that were not treated with AHC. The effect of AHC on time spent in each behaviour differed between infected and uninfected calves and increased the coefficient of dispersion of the behavioural data. Conclusions and clinical relevance: Small differences in animal behaviour can be measured in calves with GIP. However, to use this to target treatment, further validation studies are required to confirm the accuracy of behavioural classification and understand the complex drivers of animal behaviour in a dynamic and variable pasture-parasite–host environment.
Open Access
An exploration into the sleep of workers on block-calving, pasture-based dairy farms
(Elsevier on behalf of the American Dairy Science Association ®, 2024-07-04) Hall, LS; Edwards, JP; Dale, K; Westbrooke, Victoria; Bryant, Racheal; Kuhn-Sherlock, B; Eastwood, CR
The benefits of sufficient and high-quality sleep for people are well documented. Insufficient sleep increases the risk of accidents, injuries, and negative health implications for people. This is especially relevant for farmers, as they work with large animals and machinery. Dairy farming often requires early start times and long days, particularly over the high workload calving period in block calving, pasture-based systems. However, there is little published data quantifying the sleep quantity and quality of farmers over this period. In this study, the sleep patterns of workers (n = 33) on 10 New Zealand dairy farms was measured for 90 d over the spring calving period using a sleep measuring device (OuraTM ring, Oura Health Ltd., Oulu, Finland). Total sleep time (TST) averaged 6 h 15 min, lower than the required 7 to 9 h for optimal wellbeing and cognitive functioning. TST decreased over the calving period and was significantly correlated with both sleep start and wake times. Factors such as work start time, farm location, and role on farm influenced sleep quantity and quality; indicating adjusting these on-farm factors could positively impact TST. Further research is required to better understand sleep and its effect on dairy farmers, over both the calving period and the remaining months of the year.
Embargo
Novel drivers of voluntary intake of low dry matter forages in sheep : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2023) Jayasinghe, Nadeesha Kumari
Fresh forages account for a significant part of the ruminant’s diet in pasture-based systems. Previous studies have suggested dry matter content below 16% reduce dry matter intake, but contemporary NZ temperate grazing systems using a range of low DM% forages are reported to have strongly positive production features, so, an experimental series (1, 2 and 3) was designed to assess DMI using fodder beet (FB), plantain, chicory and ryegrass cultivars using young sheep. In experiment one, DMI, water intake, urine volumes and mineral (Na, K, Ca, Mg, P) balance were measured with young sheep using metabolism crates and fresh harvested FB to represent a total diet DM% below 14%, with grass silage (GS) as a control. Eight (49±1.75 kg) Coopworth hogget rams were fed one of the three treatments, sequentially in runs 1 to 3; treatment 1 (ad libitum GS) - FB 0%: GS 100%; treatment 2 (restricted FB) - FB 30%: GS 70%; treatment 3 (ad libitum FB) - FB 90%: GS 10%. Total diet DM% were 43.21, 30.44, and 13.56%; total diet CP% were 13.38, 13.97, and 12.18%; and total diet NDF was 57.19, 43.13, and 22.29%, respectively for runs 1, 2 and 3. In run 3 the mean daily DMI was greater at 2.74% of LWT compared to run 2 (2.21%) and run 1 (2.49%) (p<0.05). Mean daily water intake in run 3 was 239 ml/kg of LWT, fourfold higher (p<0.05) than observed in run 1 (61 ml/kg of LWT). Mean daily urine production in run 3 was 160 ml/kg LWT, significantly greater (p<0.05) than observed in run 1 or run 2. The mean daily Na intake in run 3 was 21.27 (g/d), significantly greater than runs 1 and 2 (p<0.05), with greater (p<0.05) urinary Na concentration and mean daily urinary Na output in run 3, increasing from 105 to 2090 (mg/L) and 0.14 to 17.89 (g/d) runs 1 to 3. Mean daily N intake was not different between runs, while mean daily urinary N output (g/d) was significantly lower in run 3 (6.19g/d) compared to run 1 (7.88 g/d). Urinary N% was greater in run 1 than run 2, and run 3 (0.6, 0.28 and 0.08% respectively). The N utilization (N retained/total diet N) was greater in run 3 (67%) compared with run 1 (35%) and run 2 (33%). The DMI observed in run 3 was high by comparison with other pen fed harvested forage studies, but lower than the intake observed in grazed forages of similar DM%, and neither the NDF intake nor the CP content of the diet likely limited intake. There was no evidence of rumen dysfunction, and it was concluded that, when FB was fed ad libitum, despite being a low DM% forage, high DMI could be achieved, and the very high urine volumes observed suggested a role for Na in excreting the considerable water load consumed with these DMI. However, it was not clear whether all these effects could be related to an effect of increased Na intake in ad libitum FB diet. Plantain and chicory are low DM% forages that have higher Na content compared to ryegrass, and comparatively high N content compared to FB. Therefore, the second experiment was conducted to investigate the role of Na in DMI in low DM% forages, using eight different plantain varieties, chicory, and ryegrass, in four different sequential runs. In each run, 32 young sheep (41±7kg) were used in four groups of eight animals, with the first two runs using the same sheep and forages on a 14d delay and were conducted as sequential runs. In runs 1 and 2 the treatments were tonic, agritonic, ecotain (plantain varieties) and ryegrass, and in run 3 the treatments were tonic, captain, SF and oracle (plantain varieties), and in run 4 the treatments were tonic, tuatara, boston (plantain varieties) and chicory. In all four runs, ad libitum feed was given (refusals > 20%). Despite low DM% (8.47 to 16.56%), plantain and chicory treatments recorded significantly higher (p<0.05) DMI compared to the grass treatments where DM% varied from 13.06 to 16.17%. The DMI/fasted LWT varied from 3.1 to 5.0, 3.5 and 2.6 to 3.2% respectively for plantain, chicory and grass, and the mean daily NDF intake for plantain and chicory varied from 0.74 to 1.64% (NDF/LWT), and for grass 1.17 to 1.22%. The mean daily urine production was highest in the chicory treatment (11654 ml/d), and expressed against fasted LWT, 177 to 294 ml/kg for the plantain and 98 to 118 ml/kg for the grass treatment. Mean daily Na intake in plantain varied (0.3 to 10.57 g/d) across runs, but all except boston and tuatara treatments were >3g/d, while the chicory treatment was 3.5g/d, and both mean plantain and chicory values were significantly greater (p<0.05) than the mean of the grass treatments (0.43 g/d). The plantain treatments in runs 1 and 2 had greater (p<0.05) mean daily urinary Na concentration and mean daily urinary Na outputs (g/d) compared to the grass treatments. The mean daily Na intake (3.51 g/d) was lower in the chicory treatment, and the mean daily urinary Na output for chicory treatment (3.51 g/d) was equal to the intake. Despite the plantain DM% doubling from run 1 to run 2, the mean daily total water intakes were closely similar between runs within plantain treatments (range 378-398 vs 366-376 ml/fasted LWT, respectively for run 1 and run 2). When the mean daily DMI was expressed against LWT, run 2 plantain treatments were observed to have the highest for any treatment (4.62 to 5.08% of LWT) in all four runs, and it was concluded this water intake was an effective upper physiological limit, thereby limiting DMI. The results from this experiment do not support the hypothesis that forage DM% below 16% restrict DMI, and it was concluded that a total water intake of approximately 370-400ml/ kg LWT represents a physiological upper water intake limit, and that a daily urinary Na concentration of approximately 300mg/L, and a daily urinary Na output of approximately 3.5g was required to enable corresponding urine outputs to achieve the DMI observed. It was also concluded that diet Na content and daily intakes facilitated water excretion, and that only sufficient Na intakes would therefore enable high DMI with low DM% forages. The third experiment was conducted to investigate the effect of Na on DMI and urine production when the animals were externally dosed with Na while feeding on low DM% pasture that was originally low in Na. Twenty-four young sheep (39±5 kg) were divided into three groups of eight and three dietary treatments were used in two sequential runs in a cross-over design (grass and grass + salt treatments). The ad libitum FB treatment was maintained as the control treatment in both runs, while the other dietary treatments were grass and grass + salt (12 g of Na was added via oral drenching to achieve a daily intake similar to that of ad libitum FB feeding treatment). The mean daily DMI and the mean daily DMI/fasted LWT were significantly lower (p<0.05) in the FB treatment in both runs 1 and 2, and no significant differences (p<0.05) were observed between the grass treatment or grass + salt treatments in DMI or DMI expressed against LWT. The mean daily NDF intake expressed against the LWT was significantly higher (p<0.05) in the grass treatment and grass + salt treatments compared to the FB treatment and varied from 1.14 to 1.22% from run 1 to run 2. The mean daily urine production (ml/d) was not significantly different (p<0.05) between treatments in run 2, but in run 1 the grass + salt treatment was greater than the FB treatment. The mean daily total water intake expressed against fasted LWT were significantly higher (p<0.05) in grass and grass + salt treatments than the FB treatment, while in run 2, none of the treatments were found to be significantly different. The mean daily feed Na intake (g/d) was significantly higher (p<0.05) in the grass + salt treatment than in grass treatment in both runs. Despite the five to tenfold greater mean daily Na intake in the grass + salt compared to the grass treatment, there were no significant differences in mean daily urine production among the grass and grass + salt treatments in run 1 or 2. The urinary Na concentration was significantly increased (p<0.05) in the grass + salt treatment compared with the grass treatment (1316 vs 223 mg/L). The mean daily urinary Na mass output (g/d) was significantly higher (p<0.05) in the grass + salt treatment in both runs compared to the grass treatment. In both run 1 and run 2, grass + salt treatment had significantly higher (p<0.05) urine production (ml) and urinary Na output (g) in the early part of the diurnal period compared to that with the latter part. However, both grass and the FB treatments did not significantly differ in urine production (ml) and urinary Na output (g/d) during the diurnal period. It was concluded that supplemented Na does not necessarily increase the DMI or the urine volume in the grass + salt treatment despite the grass treatment being low in DM% (<16%), when the DMI was likely to be initially restricted by the NDF intake (1.14 to 1.22% NDF/LWT), and the excess of Na intake could have led to increase the urinary Na concentration once the minimum Na intake has been reached without necessarily increasing the urine production. It was concluded the lower DMI observed in the FB treatment was most likely a result of the CP content of the FB diet (8.06-8.38%) limiting the RDP of the diet. From the results of this series of experiments it was concluded that when FB was fed ad libitum, despite being a low DM% forage (<16%), high DMI could be achieved, and therefore high urine volumes were associated with this intake. It was also concluded that low DM% in forages did not restrict DMI if the animals consumed sufficient daily Na intake to enable high urine outputs of a minimum Na concentration (c.300mg/L) required for diuresis, and if the animals remained below a physiological upper water intake limit of approximately 370-400ml/ kg LWT, which was observed with the DMI observed in very low DM% forages such as some plantain and chicory treatments in this study. This process required a daily Na output of approximately 3.5g to enable corresponding urine outputs allowing the DMI to be increased in low DM%. However, supplementary Na does not necessarily increase the DMI or the urine volume despite the forage being low in DM% (<16%) if the DMI is restricted by the NDF intake, suggesting Na supplementation on most NZ ryegrass pastures will not be effective. In such cases, the excess of Na intake leads to an increase in urinary Na concentration once the minimum Na intake has been reached without necessarily increasing the urine production or the DMI.
Open Access
In vitro evaluation of potentially edible Brazilian trees and shrubs in ruminant nutrition
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-11-29) de Morais, JPG; Campana, M; Gregorini, Pablo; Garcia, TM; Minussi, JFDA; Pereira, SN; Pereira, FC; Del Valle, TA
The present study aims to evaluate the nutritional value of different tree and shrub leaves in Brazilian ruminant production systems. Eight potentially edible trees and shrubs were identified from interviews with 30 ruminant producers: Aroeira (ARO; Lithraea molleoides), Black Mulberry (BMU; Morus nigra), Candeia (CAN; Eremanthus erythropappus), Jatobá (JAT; Hymenaea courbaril), Gliricídia (GLI; Gliricidia sepium), Santa Bárbara tree (SBT; Mélia azedarach), Tithonia (TIT; Tithonia diversifolia), and White Mulberry (WMU; Morus alba). Four leaf samples of each edible tree were sampled, and chemical analyses and in vitro assays were performed. Edible trees (except CAN and JAT) had lower neutral detergent fiber content than Mombasa grass. In addition, SBT, BMU, WMU, and TIT had lower fiber content than the other evaluated edible trees. Consequently, SBT, TIT, BMU, and WMU had improved dry matter degradation. Among the edible trees and shrubs, SMW and WMU increased the potential for gas production (a parameter). On the other hand, CAN decreased the estimated gas production 48 h after incubation. Furthermore, TIT decreased methane production up to 24 h after in vitro fermentation. Thus, except ARO, CAN, and JAT, the edible trees evaluated in the present study are potential feeds in moderate- to high-producing animals. Additionally, TIT fermentation reduces in vitro methane production.
Open Access
Diverse Bradyrhizobium spp. with similar symbiosis genes nodulate peanut in different regions of China: Characterization of symbiovar sv. Arachis
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-11-06) Zhang, J; Feng, Y; Wang, J; Wang, E; Andrews, M
A total of 219 rhizobial strains isolated from peanut grown in soils from six peanut croplands in Zhengyang county, Henan Province, were typed by PCR-RFLP of IGS sequences. Their phylogenetic relationships were refined on representative strains using sequence analyses of 16S rRNA genes, housekeeping genes (atpD, recA, glnII) and symbiosis genes (nodA, nodC and nifH). The 219 rhizobial isolates were classified into 13 IGS types, and twenty representatives were defined within eight Bradyrhizobium genospecies: B. guangdongense covering 5 IGS types (75.2% of total isolates), B. guangzhouense (2 IGS types, 2.7% total isolates), B. zhengyangense (1 IGS type, 11.3% total isolates) and five novel genospecies (5 IGS types, 0.9 to 3.2% total isolates). All representative strains had identical nodA, nodC and nifH sequences except for one nifH sequence. With this one exception, these sequences were identical to those of the type strains of Bradyrhizobium species and several Bradyrhizobium genospecies isolated from peanut in different regions of China. The nodC sequences of all strains showed < 67% similarity to the closest strains on the Genbank database indicating that they are representative of a novel Bradyrhiobium symbiovar. This study has shown that (1) diverse Bradyrhizobium spp. with similar symbiosis genes nodulate peanut in different regions of China. (2) Horizontal transfer of genes involved in nodulating peanut is common between Bradyrhizobium species in soils used to grow the crop in China. (3) The strains studied here are representative of a novel Bradyrhizobium symbiovar that nodulates peanut in China. We propose the name sv. arachis for this novel symbiovar indicating that the strains were isolated from Arachis hypogaea. Results here have practical implications in relation to the selection of rhizobial inoculants for peanut in China.
Open Access
Effects of winery wastewater to soils on mineral properties and soil carbon
(MDPI, 2024-06) Nightingale-McMahon, M; Robinson, B; Malcolm, B; Clough, Timothy; Whitehead, D
Winery wastewater (WW) is a high-volume biowaste and, in the context of Marlborough and New Zealand wineries, there is a growing recognition of the need to improve current WW disposal systems to mitigate negative environmental impacts. The application of WW to land is a low-cost method of disposal, that could significantly reduce the environmental risk associated with WW directly entering surface and groundwater bodies. This study analysed elemental concentrations in WW and soils from three Marlborough vineyards across their annual vintage to determine the loading rates of nutrients into WW and the subsequent accumulation effects of WW irrigation on receiving soils. The findings showed loading rates of approximately 1.8 t ha‾¹ yr‾¹ of sodium within WW and a significant increase in soil sodium concentration and pH, attributed to sodium-based cleaning products. A loading rate of approximately 4 t ha‾¹ yr‾¹ of total organic carbon was also identified within WW, however, significant losses in soil carbon, nitrogen, magnesium and calcium concentrations were identified. Focusing efforts to retain key nutrients from WW within soils could provide benefits to New Zealand’s wine industry, facilitating increased biomass production in irrigation plots, thereby increasing biodiversity and potentially generating incentives for vineyard owners to contribute to increasing biomass carbon stocks and offset agricultural greenhouse gas emissions.
Open Access
Supplementing diets with Agriophyllum squarrosum reduced blood lipids, enhanced immunity and anti-inflammatory capacities, and mediated lipid metabolism in Tan lambs
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-12) Jiao, D; Liang, Y; Zhou, S; Wu, X; Degen, AA; Hickford, Jonathan; Zhou, Huitong; Cong, H; Shi, X; Ma, X; Yang, G
Agriophyllum squarrosum (sand rice), a widespread desert plant, possesses anti-hyperglycemic and anti-inflammatory properties, and has been used in traditional Chinese medicine for many years. However, its effects on ruminants are unknown. To fill this gap, we examined the effects of A. squarrosum on the immune and anti-inflammatory responses of lambs. A total of 23, 6-month-old Tan ewe-lambs (27.6 ± 0.47 kg) were divided into four groups and offered a basic diet (C—control), or a diet that contained 10%, 20%, or 30% A. squarrosum, on a dry matter basis, for 128 days. Serum concentrations of total cholesterol were lower (p = 0.004) in the 30% supplemented lambs than controls, while concentrations of high-density lipoprotein cholesterol were lower (p = 0.006) in the 10% and 20%, but not in 30% supplemented lambs than controls. Serum-cortisol concentrations were lower (p = 0.012) in the 30% supplemented lambs and free fatty acid concentrations were higher in the 10% and 20% supplemented lambs than in control lambs (p < 0.001). Supplementation with A. squarrosum decreased (p < 0.05) the area of adipocytes in subcutaneous adipose tissue, but there was no difference between the 20% and 30% diets. Conversely, the area in visceral adipose tissue (VAT) increased (p < 0.05), especially for the 10% and 20% supplemented diets. Supplementation with A. squarrosum also enriched immune and anti-inflammatory related and lipid and glucose-metabolic pathways and associated differentially expressed gene expressions in adipose tissue. A total of 10 differential triacylglycerol, 34 differential phosphatidylcholines and seven differential phosphatidylethanolamines decreased in the diet with 30% supplementation, when compared to the other diets. Finally, adipocyte-differentiation genes, and immune and inflammatory response-related gene expression levels decreased in lamb adipocytes cultured with an aqueous A. squarrosum extract. In conclusion, supplementing lamb diets with A. squarrosum reduced blood lipids, enhanced immunity and anti-inflammatory capacities, and mediated lipid metabolism in adipose tissue and adipocytes of Tan lambs. A level of approximately 10% is recommended, but further research is required to determine the precise optimal level.
Open Access
Spatial agroecology: modelling multiple ecosystem services in periurban landscapes : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Morris, Richard Minton
Urban growth and agricultural intensification share a common trait of reducing landscapes' capacity of producing the critical ecosystem services (ES) on which they depend. The objective of the work described in this thesis was to develop a spatially explicit ES-based design method for the configuration of landscapes to generate regulating ES. Literature review, which is described in Chapter 2, identified a nexus of four research fields - Ecological Urbanism, Landscape Ecology, ES science and agroecology - as an unexplored framework for this ES-based design approach. The method used in this work is described in Chapter 3, where a key flaw in current ES modelling tools forms the basis for a Geographic Information Systems (GIS)-based conceptual model, ESMAX. Present models are characterised by 'the biophysical gap', an oversight of spatial interactions between ES-supplying landscape components. This inhibits their application to spatial design i.e., the configuration of those components to enhance ES performance. ESMAX is structured around the fundamental natural phenomena of distance-decay as exhibited by all regulating ES, enabling an original method of quantifying and visualising regulating ES produced by different configurations of landscape components. The results of Chapter 3 conceptually validated the model and provided the data for Chapter 4, which proposed a model for assessing landscape multifunctionality (or simultaneous supply of multiple ES) from different landscape configurations. Importantly, the results for different configuration options generate a solution space with which to negotiate specific ES demands and specific contextual spatial constraints. Chapter 5 applied ESMAX and the solution space in an agricultural context. This spatial agroecological approach determined that different configurations of the same total area of trees in a 1 ha paddock produce markedly different levels of ES performance, and that this approach may be useful in supporting an adaptive transition from conventional agriculture to agroecologically based farming systems. Chapter 6 applied spatial agroecology to a 190 ha periurban development site, demonstrating how the same apportioned area of agroecological systems, when subdivided and distributed differently across the site, has a significant bearing on multiple ES production. This suggests that urgent consideration should be given not only to placing trees on farm, but how trees should be placed on farm. Similarly, it supports not only the integration of agriculture with urban systems, but the specific spatial design of agroecological systems to address the regulating ES demands of the urban system. The spatial agricultural approach outlined in this thesis highlights the potential for agroecology in the Anthropocene as a spatially effective source of multiple regulating ES to surrounding communities at various scales.

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