Journal Articles
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Item Increased growth rate post-weaning affects mammary gene expression of two-year-old ewes during their second pregnancy and lactation(Oxford University Press on behalf of the American Society of Animal Science., 2025-09-18) Haslin E; Herath HMGP; Pain SJ; Gedye KR; Sneddon NW; Wang B; Heiser A; Corner-Thomas RA; Kenyon PR; Morris ST; Blair HTThis study examined the long-term effects of increased growth rates between three and seven months of age on gene expression in the mammary gland of nondairy ewes during their second lactation. A total of 19 twin-bearing, two-year-old ewes that either had an increased growth rate between three and seven months of age (heavy; n = 9; 153 ± 2.2 g/d and 47.9 ± 0.38 kg at breeding) or did not have an increased growth rate (control; n = 10; 127 ± 1.9 g/d and 44.9 ± 0.49 kg at breeding) were selected. Mammary gland biopsies were collected at day 128 of pregnancy and day 30 of lactation to examine the expression of 37 genes involved in mammary cell development and milk fat metabolism using NanoString nCounter technology. Ewes in the heavy group tended to exhibit lower expression (P < 0.05) of acyl-CoA synthetase short-chain family member 1 (ACSS1), a gene critical for mitochondrial acetyl-CoA synthesis, energy production, and milk fat synthesis, and a trend toward (P = 0.11) lower expression of signal transducer and activator of transcription 5A (STAT5A), a regulator of mammary epithelial cell differentiation and survival. These lower expressions suggest potential carry-over effects of increased growth rate between three and seven months of age. However, no phenotypic differences were observed in lamb growth or live weight, and no differences were detected in the expression of downstream target genes or modulators of these pathways, suggesting limited functional impact on mammary gland development and lamb performance outcomes. Further investigations, including a functional assessment of lactation and use of comprehensive transcriptomic analyses, would be needed to understand the effects of increased growth rates between three and seven months of age on ewe mammary function and milk composition.Item A comparison of three nutritional models for estimating total metabolisable energy requirements for a ewe, beef breeding cow, lamb, and a calf/yearling in New Zealand's pasture-only system(Elsevier B V, 2025-09-01) Adjabui JA; Morel PHC; Morris ST; Kenyon PR; Tozer PRIn New Zealand (NZ), the metabolisable energy requirements (MER) of ruminants can be estimated using nutritional models from Nicol and Brookes (2017), CSIRO (2007), and NZ's Agricultural Inventory Model (AIM) of the Ministry for Primary Industries [MPI] (2022). The aim in this study was to calculate the total MER of a ewe, beef breeding cow, lamb, and a calf/yearling in a pasture-only system in NZ under the same assumptions to assess the extent and reasons for variations among the three commonly used nutritional models, and the implications for a given farm/s. The study utilised MER models from the three sources above using a factorial method. This method determines the MER for each physiological phase of an animal, to estimate total MER for each animal. The AIM (MPI 2022) model relative to Nicol and Brookes (2017), and CSIRO (2007) models respectively, estimated 13.4 % and 8.0 % higher MER for a ewe, 16.3 % and 16.6 % for a cow, 1.1 % and 2.0 % lower for a lamb, and 9.2 % and 9.2 % higher for a calf/yearling mainly due to a higher maintenance MER compared to the other models. This has implications for feed budgeting and stocking rates (SR) for a given farm, as the AIM (MPI 2022) model leads to a lower SR than the other two models for a given level of feed available. Energy balances and productivity could be negatively impacted if a model underestimates MER. This also yields different greenhouse gas (GHG) profiles, especially enteric methane, for a given farm and could potentially have financial consequences for farmers if an Emissions Trading Scheme was introduced. For consistency in ME estimates and GHG reporting, further research (feeding trials) is required to compare these model estimates to actual requirements of ruminants under NZ conditions. This could help identify the model that most accurately reflects MER for ruminants in the country.Item Characterisation of the nutritional composition of plant components of a herb-clover mix during November to May in New Zealand(New Zealand Society of Animal Production, 2019-07-01) Ekanayake WEMLJ; Corner-Thomas RA; Cranston LM; Hickson RE; Kenyon PR; Morris STAnimal performance on herb-clover mixes (containing plantain, chicory, red clover and white clover) can be inconsistent. Potentially this could be due to variation in botanical and nutritional composition of plant components affecting animal selectivity and, thus, performance. Herbage samples were collected monthly from November 2016 to May 2017, from 3 paddocks located at Massey University’s Keeble farm, Palmerston North, New Zealand. Quadrat-cut samples were used to determine the herbage mass and botanical composition. Hand-plucked samples of each plant components were analysed for the nutritional composition. The botanical composition of the herb-clover mix differed over time (P<0.05). The percentage of chicory stems increased (9.2 to 16.2%) and plantain stems decreased (14.7 to 1.0%, P<0.001). Overall, the crude protein and metabolisable energy of white clover, red clover, plantain and chicory leaves were higher (P<0.05) than those of plantain and chicory stems in each month except in November. These data indicate that a higher proportion of chicory and plantain stems in a herb-clover mix would reduce overall metabolisable energy and crude protein. This information can be useful for farmers to manipulate both the botanical and nutritional composition of herb-clover mix to optimise animal performance.Item Feed profile analysis of oil palm-integrated beef cattle farming systems by metabolic energy budgeting and implications for beef production and pastoral system design(John Wiley & Sons Australia, Ltd on behalf of Chinese Grassland Society and Lanzhou University, 2023-04-17) Gobilik J; Baco H; Kabul MA; Dollah S; Morris ST; Matthew C; Nan ZBackground: Oil palm is a tropical crop with worldwide plantings approaching 20 million ha and large areas in Indonesia, Malaysia and Thailand. The plantations are readily managed as silvopastoral systems incorporating cattle grazing (Oil Palm Silvopastoral System for Cattle, OPSC) but there is a need for analytical tools and data to understand system herbage supply and feed conversion efficiency (FCE). Methods: Metabolic energy budgeting was used to estimate herbage harvested by cattle in three OPSC subsystems, 9 and 12 years after oil palm establishment, and FCE of the subsystems was determined. Understorey herbage was also analysed for nutritive value, botanical composition and herbage accumulation within one grazing-regrowth cycle. Results: The herbage-harvested estimate was 2.0−2.4 t dry matter (DM) ha−1 year−1 for 9 year old subsystems and 1.4−1.7 t DM ha−1 year−1 for a 12 year old subsystem. Herbage metabolisable energy (ME) was 8.3−8.5 MJ kg−1 DM and crude protein (CP) was 15%−16% DM. FCE values for subsystems ranged from 32 to 94 kg DM kg−1 liveweight-gain. Conclusions: Herbage DM yield is declining, while herbage ME is marginal but CP is adequate. FCE is suboptimal but can be optimised by defining the trajectory of declining herbage production with canopy closure as plantations age and matching stocking rate to herbage supply using a comparative-stocking-rate-type statistic.Item Wool shedding and lamb fleece weights: first-cross and backcross Wiltshire–Romney sheep scored at lamb, hogget and two-tooth ages(Taylor and Francis Group, 2024-05-03) Sneddon NW; Handcock RC; Corner-Thomas RA; Kenyon PR; Burnham DL; Garrick DJ; Littlejohn MD; Blair HT; Morris STWith decreasing wool values, interest is increasing regarding shedding sheep. To investigate this, two long-term studies introducing Wiltshire genes into Romney flocks were initiated. Data from these two studies provide phenotypic relationships between a range of shedding scores at different ages. The data included shedding scores (on a 0–5 scale) repeated on lambs (∼5 months), hoggets (∼14–18 months) and two-tooths (∼27 months), and lamb fleece weights. Positive relationships between shedding scores on the same animals were observed. Lamb fleece weight was negatively correlated with all shedding scores. Lamb shedding score in February had a correlation of 0.54 (P < 0.001) with the February score as a hogget at Riverside farm. Scoring wool shedding is a laborious activity requiring individual animals to be scored in the shearing position. Therefore, lamb fleece weight was investigated for its relationship with shedding scores, as a potentially easier alternative. Lamb fleece weight had a greater correlation with February hogget shedding score than with the lamb shedding score (−0.76 vs −0.52, P < 0.001). This study indicated that February scores are an accurate predictor of future shedding phenotypes, and when used in conjunction with fleece weight, are a good predictor of phenotypes expressed at later ages.Item Effects of yard weaning and human contact compared to paddock weaning on the liveweight gain and stress reactivity of beef cattle(Taylor and Francis Group, 2023-09-03) Cranston LM; Ramsay BA; Schoorl J-AAJ; Stayton KM; Greaves A; Shanks RD; van Kampen CJ; Cockrem JF; Beausoleil NJ; Morris ST; Sneddon NW; Hickson REIn New Zealand beef herds, calves undergo ‘paddock weaning’ by separating calves and cows into different paddocks. Anecdotal evidence indicates ‘yard weaning’ whereby calves are yarded and receive regular human contact during weaning may improve long-term stress reactivity and growth rates. Calves were allocated to one of three treatments for seven days post-separation from dams: paddock weaned with minimal human interaction (PN), paddock weaned with daily human interaction (PV), yard weaned with daily human interaction (YV). Calf liveweight, behavioural and physiological measures of stress reactivity and faecal corticosterone concentration were measured. Until day seven, YV calves lost less liveweight than PV or PN calves (0.5 kg vs. 3.5 and 4.8 kg P < 0.05). On day seven, PN calves had a 23% greater heart rate compared to YV calves and a greater faecal corticosterone concentration than PV and YV calves (in cohort 2 only) (P < 0.05). This indicates, regular non-aversive human contact during weaning may reduce stress associated with the weaning process itself and reduced stress reactivity to subsequent handling and restraint. However, this effect was transient with no consistent longer-term benefits over traditional paddock weaning, in terms of growth or stress reactivity to human handling.Item Comparison of meat quality characteristics of lambs weaned at eight or 14 weeks of age grazing perennial ryegrass-white clover or a plantain-clover mix(New Zealand Society of Animal Production, 2019-07) Kok JC; Schreurs NM; Cranston LM; Corner-Thomas RA; Ekanayake WEMLJ; Morris ST; Kenyon PRThis study compared the meat quality of lambs grazing either perennial ryegrass-white clover pasture or a plantain-clover mix (plantain, red clover, and white clover) from eight to 14 weeks of age followed by a six-week finishing period on perennial ryegrass-white clover pasture. Ewes and their lambs were allocated to four treatments: 1) lambs weaned early (eight weeks of age) on a plantain-clover mix (EARLY), 2) lambs with dam grazing a plantain-clover mix (HERB), 3) lambs with dam grazing pasture >1200 kgDM/ha (HIGH), and 4) lambs with dam grazing pasture <1200 kgDM/ha (LOW). Following the treatment period, all lambs weighing a minimum of 35 kg were sent for slaughter and all remaining lambs were managed and finished as one mob on perennial ryegrass-white clover pasture for a further six weeks. Lambs that reached a minimum 35 kg live weight were slaughtered and meat samples from each lamb were analysed for ultimate pH, meat colour (L*, a*, b*), drip loss and shear force but, no difference was found in objective meat quality characteristics of lambs from different treatments.Item Adoption of leucaena-based feeding systems in Sumbawa, eastern Indonesia and its impact on cattle productivity and farm profitability(International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS), 2019-09-03) Dahlanuddin; Panjaitan T; Waldron S; Halliday MJ; Ash A; Morris ST; Shelton HMLeucaena has been fed to cattle by the Balinese community in Sumbawa and West Sumbawa districts on Sumbawa Island since the 1980s. However, prior to 2011, this practice was not adopted by the local Sumbawanese farmers. Since then, a model leucaena-based cattle fattening system was developed in Sumbawa and West Sumbawa districts in a collaborative research project between the Assessment Institute for Agricultural Technology (BPTP), University of Mataram and The University of Queensland (UQ) funded by the Australian Centre for International Agricultural Research (ACIAR), followed by a scaling-out project involving collaboration between the University of Mataram and CSIRO (Applied Research and Innovation Systems in Agriculture -ARISA project) funded by DFAT (Department of Foreign Affairs and Trade)promoting public-private partnerships. Further promotion of leucaena-based fattening systems occurred in Dompu, Sumbawa, through a project with the University of Mataram and Massey University funded by the New Zealand Ministry of Foreign Affairs and Trade(MFAT). By the end of October 2018, more than 2,500 farmers on Sumbawa Island were practicing leucaena-based cattle fattening. The main drivers of adoption of cattle fattening with leucaena were: (1) The high growth rates achieved (0.4–0.6 kg/d for bulls fed 100% leucaena and 0.66 kg/d when maize grain was added to the leucaena basal diet) compared with 0.16 kg/d for the traditional system, combined with high profitability; (2) the needs of farmers being met in terms of relevance and cultural appropriateness; (3) field extension staff being well trained and mentored, and respected by the farmers; (4) the local government being highly supportive of leucaena-based cattle fattening; and (5) additional benefits being increased dressing percentage and high carcass quality. The rapid increase in the use of leucaena for cattle fattening in eastern Indonesia is expected to have a significant positive impact on household incomes as well as on regional economic growth.Item Should lambs born to one-year-old ewes and grown to heavy live weights be retained as replacements and mated at seven months of age?(Taylor & Francis Group, 2024-02-21) Haslin E; Kenyon PR; Corner-Thomas RA; Morris ST; Blair HTThe lifetime productivity and efficiency of singleton- and twin-born ewe lambs born to one-year-old ewes were compared with twin-born ewe lambs born to mixed-age ewes. Romney ewe lambs either born as twins to mixed-age ewes (Heavier n = 135 and Control n = 135), or to one-year-old ewes as singletons (L1; n = 135) or twins (L2; n = 88) were included. The Heavier ewes weighed 47.9 ± 0.36 kg at ewe lamb breeding while Control ewes weighed 44.9 ± 0.38 kg. The lifetime number of lambs born and weaned, and the lifetime weight of lambs weaned were used to calculate both feed and ewe efficiency. Heavier ewes had greater lamb production as one-year-old ewes than L1, L2 and Control ewes, after which the yearly lamb production and efficiency did not differ between treatments. Heavier ewes had a greater lifetime number and weight of lambs weaned than L1 and L2 ewes but did not differ from Control ewes. The lower lifetime production of L1 and L2 ewes was driven by their low production as one-year-old ewes. Farmers, therefore, could select their replacements from ewes born to one-year-old ewes and have similar lamb production to ewes born to mixed-age ewes, providing they reach recommended pre-breeding live weights.Item Effects of Increased Growth Rates Prior to the First Breeding as Ewe Lambs and Pregnancy Rank on Mammary Glands of Two-Year-Old Ewes(MDPI (Basel, Switzerland), 2021-12-01) Haslin E; Corner-Thomas RA; Kenyon PR; Morris ST; Blair HT; Ispierto IGThis study investigated potential carry-over effects of increased growth rates prior to breeding at seven months of age on mammary glands of two-year-old ewes bearing one or two lambs, and examined the association between ewe mammary structures and the growth of their progeny. Ewe live weight and mammary ultrasound measures were recorded at 119 days of pregnancy, 29 days of lactation (L29), and weaning of the progeny (L79) in 64 two-year-old ewes selected from two treatments. The heavy group (n = 32) was preferentially fed prior to their first breeding at seven months of age, achieving an average live weight of 47.9 ± 0.38 kg. The control group (n = 32) weighed an average of 44.9 ± 0.49 kg at breeding. Lambs (n = 74) were weighed at birth, L29 and L79. Udder ultrasound measures did not differ (p > 0.10) between treatments, indicating no carry-over effects of treatments on mammary glands of two-year-old ewes. The association between ultrasound measures and lamb growth seemed to differ depending on lamb birth rank. More research is needed to further investigate these associations and determine whether ultrasonography could be used to identify ewes whose progeny would have greater growth rates based on birth rank.