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The objectives of this study were to determine factors affecting lamb birth weight (BWT) and differences between BWT of the largest and smallest littermates (BWTD) and to assess the relative importance of BWT and BWTD on lamb survival and growth to weaning. Records from twin (n = 5369) or triplet (n = 1664) litters born on pasture were utilised. Breeds included Coopworth, Romney, Perendale, composite and Texel. Ewe and sire breed, age and weight of the dam, sex, and number of lambs born (NLB) affected BWT. Neither embryo loss nor ovulation pattern (i.e. all ova released from one ovary or some from each) were associated with BWT. Dam weight and NLB affected BWTD but dam age, sire or dam breed did not. Loss of an embryo reduced BWTD, and BWTD was lower when the ewe ovulated from both ovaries versus only one ovary for twins, but not triplets. Whereas BWT was moderately heritable (h2 = 0.20), BWTD was not heritable (h2 = 0.003). Lamb survival was positively associated with BWT. Lambs with BWTD > 1.3 kg were less likely to survive (73.3%) than those from litters of smaller BWTD (range 82.8–85.7% survival). Growth rate of twin and triplet lambs was positively associated with BWT. Surprisingly, lambs from litters with moderately high BWTD had slightly greater (approximately 3%) growth rate than those from lambs of low to intermediate BWTD. Thus, while large BWTD were negatively associated with survival, BWT itself, which was moderately heritable, appeared to be a stronger driver of lamb survival and average daily gain.

AbstractThis study evaluated the effect of early weaning (EW) of artificially reared lambs using a restricted milk replacer (MR) feeding and step-down weaning system on the short- and long-term effects on growth, feed intake, selected blood metabolites and hormones, body composition, and small intestine development. Mixed-sex twin-born 2 to 5 d old lambs were randomly allocated to individual pens and fed MR at 20% of initial individual BW in week 1 and 15% in week 2 followed by weaning off MR by the end of week 4 (EW; n = 16) or week 6 (Control; Ctrl, n = 16) using a step-down procedure. Concentrate starter and fiber diets were offered ad libitum to week 9, then gradually removed over a 10-d period. All lambs were managed as a single group on pasture from weeks 6 to 16 of the trial. Feed intake was recorded daily in the first 6 wk, and BWs recorded weekly. At weeks 2, 4, 6, and 8, and pre- and postclostridial vaccination at week 8, blood samples were collected for analysis of selected blood metabolites, IGF-1, and immune function. Body composition was evaluated in eight animals per group at weeks 4 and 16 after euthanasia, and duodenal samples collected for histomorphometric evaluation. Early weaned lambs had lower DM, ME, CP, and NDF intake than Ctrl lambs at 21, 15, 21, and 36 d of rearing, respectively (P < 0.001), driven by lower intakes of MR from day 15 (P < 0.001) as per the experimental design, and lower total DMI of fiber (P = 0.001) from 21 to 42 d of rearing. Lamb BW tended (P = 0.097) to be lower in EW than Ctrl lambs from 5 to 10 wk of rearing, with lower ADG in EW lambs from weeks 3 to 6 (P = 0.041). Early weaning had negligible effects on duodenal morphology, organ, and carcass weights at weeks 4 and 16. Plasma metabolites (urea nitrogen, triglycerides, NEFA, glucose, and total protein) were similar between groups, while β-hydroxybutyrate was greater in EW than Ctrl lambs at weeks 4 and 6 (P = 0.018) but not week 8 indicative of early rumen development. Serum IGF-1 tended to be lower in EW than Ctrl lambs from weeks 2 to 6 only (P = 0.065). All lambs developed antibody responses postvaccination and there was no effect of treatment (P = 0.528). The results of this study illustrate that artificially reared lambs can be weaned off MR by 4 or 6 wk of rearing without compromising growth, small intestine morphology, major organ development, and body composition, nor immune function at either 4 (preweaning) or 16 (postweaning) wk of age.

This study aimed to evaluate intake, body growth, and the development of the rumen, mammary gland, and immune system in Holstein Friesian calves reared for 100 d on the commercially available feed FiberStart (conserved alfalfa, Medicago sativa; Fiber Fresh Feeds Ltd., Reporoa, New Zealand) and fed calf milk replacer (CMR) for either 56 or 91 d. Eighty calves (40 bulls and 40 heifer calves) were reared indoors in groups (n = 5 of the same sex/pen). All calves were fed 4 L of CMR/d (175 g/L of CMR) in 2 feeds/d for the first 10 d and then 1 feed/d until d 49 or 84. The calves were gradually weaned by d 56 (earlier weaned; n = 8 pens) and d 91 (later weaned; n = 8 pens). All calves were fed FiberStart ad libitum as the only solid feed source from d 1 to 100 of the study. Irrespective of treatment, all calves had similar body weights at d 0 (40.9 ± 3.0 kg) and d 49 (74.2 ± 5.1 kg) of the study. Calf sex had no effect on intake, growth, blood, and immune system parameters. Earlier-weaned calves consumed 18% more solid feed dry matter but had 16% lower body weight gain (28.9 vs. 38.5 kg, respectively) from d 56 to 100 relative to later-weaned calves, resulting in different body weight at 100 d (104 vs. 121 ± 1.3 kg). Although earlier-weaned calves could compensate for the loss of CMR dry matter and crude protein intake from d 56 to 100 by increasing forage intake, they were unable to compensate for the loss of energy from the CMR by increasing solid feed consumption. Plasma β-hydroxybutyrate concentrations were 52% greater in earlier-weaned calves than in later-weaned calves at d 84, indicating greater metabolic activity of the rumen wall. The duration of CMR feeding had no influence on humoral or cell-mediated immune functions of the calves, as evidenced by a lack of effect on antivaccine antibody responses as well as on immune gene expression. Earlier- versus later-weaned heifer calves had 5% lower mammary gland mass, indicating that greater energy supply increased mammary mass. The results of this experiment demonstrate the ability to artificially rear dairy calves on a conserved alfalfa as the only solid feed. Furthermore, earlier weaning off CMR promotes solid feed intake and an associated increase in blood β-hydroxybutyrate, an indicator of rumen development, but increasing the duration of CMR feeding improves growth and mammary gland mass by d 100. The implications of these findings on lifetime growth, health, and milk production in dairy heifers warrant further investigation.

Invertebrate biodiversity was investigated in 55 domestic gardens in the city of Dunedin in southern New Zealand. The influence of habitat types within the gardens (lawns, open beds, and closed canopy beds) on invertebrate community structure was investigated by pitfall trapping. Species richness of Coleoptera, the proportion of native species, and effects of pesticide use by householders was examined. The most abundantly trapped taxa were Collembola, Amphipoda, and Diptera. Most taxa were represented in all three habitat types, but Collembola, Diptera, and Araneae were most frequently collected in lawns and Isopoda in open beds. The use of pesticides had no effect on total trap catch, but detritivore numbers were higher in gardens where no insecticide had been used. Opiliones and Acarina were captured in greater numbers in gardens where herbicides had not been used. Over 1400 Coleoptera were identified to 164 species/morphospecies. Species richness averaged 12 species per garden. Staphylinidae, Curculionidae, and Carabidae were the most abundantly collected Coleoptera, both for species and individuals. Species richness was not affected by vegetation type. The coleopteran fauna was predominantly native (80–90%) for species and individuals. The capture of a new to New Zealand weevil species (Exomias pellicidus (Boheman)) suggests that urban studies could play a role in alerting authorities to biosecurity incursions. The study stimulated considerable interest in invertebrates from householders, which might help fill the gap between acquiring environmental awareness and encouraging changes in behaviour towards support for native biodiversity.

This study was conducted to investigate the effect of attaining puberty in the first year of life on future reproductive performance in ewes. Records were collected from 2091 ewes born between 2005 and 2009. In the first breeding season of life, receptivity to the ram was monitored to determine whether ewe lambs attained puberty or not. Ewes were then mated in order to produce a lamb at 2, 3 and 4 years of age and the following traits were measured each year: ovulation rate (OR), number of foetuses present at scanning (NLS), number of lambs born (NLB) and live weight at various time points. The percentage of ewe lambs attaining puberty was highly variable between years (p

Fire is known to cause severe and protracted reductions in some invertebrate communities. Amphipods are prone to desiccation and, therefore, litter removal through fire could be expected to have a significant adverse impact on their populations. We aimed to determine the temporal and spatial response patterns in density of amphipods following seasonal fires in a natural grassland site in southern South Island, New Zealand. Fires lit for management purposes in spring are generally cooler and considered less detrimental to the ecosystem than those occurring in hot dry summer conditions. Annual quantitative sampling was used to measure amphipod density in tussock grassland communities before and after single fire treatments were carried out in either spring or summer. Three samples were taken annually before each of the experimental fires, and for 12 years post-treatment. In general, amphipod populations took 7–9 years after treatment to recover to pre-burn densities although densities in spring burnt plots recovered more slowly. Eleven years post-burn, the spatial distribution of amphipods in relation to microhabitat was also examined. Two amphipod species were present, and they were distributed differently in tussock and inter-tussock vegetation and responded differently to fire but not to fire season. A protracted period of recovery from fire for an important member of the detritivore community is likely to have negative impacts on nutrient cycling, and therefore on primary production in grassland systems. The implication for land managers is to avoid burning in spring if soil conditions are relatively dry.

Partial neutralization of bone morphogenetic protein 15 (BMP15) bioactivity by immunization is known to increase ovulation rate in sheep. However, it remains uncertain whether BMP15 vaccination would be a suitable procedure for increasing lambing rate. The aim of this study was to compare the efficacy of a BMP15 vaccination treatment on lamb production to that of commercially-available androstenedione-based vaccines that are used for this purpose. Ewes were immunized for 3 yr against androstenedione, BMP15, or no antigen (control). Vaccination with androstenedione or BMP15 altered (P < 0.05) ovulation rate as well as litter size at midpregnancy, birth, and weaning compared with controls. No differences were detected in the proportions of ewes conceiving in the first cycle or partial failure of multiple ovulations. Both gender and litter size affected birth weight of the lamb (P < 0.05), but no effect of treatment was found. Growth rate was significantly affected (P < 0.05) by gender, birth weight, and the number of lambs raised, but not treatment. In conclusion, immunization against either androstenedione or BMP15 increased ovulation rate. Androstenedione vaccination also increased the number of lambs weaned (P < 0.05). Bone morphogenetic protein 15 vaccination altered the pattern of the number of lambs weaned, but no increase in lamb production was observed as more ewes produced zero or three lambs. Overall, androstenedione or BMP15 vaccination did not significantly affect embryo or fetal survival or lamb performance independently of the effects of these treatments on ovulation rate.

We hypothesised that cocaine- and amphetamine-regulated transcript (CARTPT) would be differentially expressed in ewes with differing ovulation rates. Expression of mRNA forCARTPT, as well asLHCGR,FSHR,CYP19A1andCYP17A1was determined in antral follicles ≥1 mm in diameter collected during the follicular phase in ewes heterozygous for the Booroola and Inverdale genes (I+B+; average ovulation rate 4) and ++ contemporaries (++; average ovulation rate 1.8). In ++ ewes (n = 6),CARTPTwas expressed in small follicles (1 to CARTPT. CART peptide was also detected in follicular fluid of some follicles of ++ ewes. In I+B+ ewes, 5/6 ewes did not have any follicles that expressedCARTPT, and no CART peptide was detected in any follicle examined. Expression pattern ofCYP19A1differed between I+B+ and ++ ewes with an increased percentage of small and medium follicles (3 to CYP19A1in the I+B+ ewes. Many of the large follicles from the I+B+ ewes appeared non-functional and expression ofLHCGR,FSHR,CYP17A1andCYP19A1was less than that observed in ++ ewes. Expression ofFSHRandCYP17A1was not different between groups in small and medium follicles, butLHCGRexpression was approximately double in I+B+ ewes compared to that in ++ ewes. Thus, ewes with high ovulation rates had a distinct pattern of expression ofCARTPTmRNA and protein compared to ewes with normal ovulation rates, providing evidence for CART being important in the regulation of ovulation rate.

Sheep lines with mutations in single genes that have major effects on ovulation rate have been very useful in gaining a better understanding of pathways important in controlling follicular development and ovulation rate. To date however, all known mutations are in the transforming growth factor beta (TGFB) superfamily. Ovulation rates were measured in 720 progeny of 20 rams that were descendants of a single prolific ewe. Evaluation of ovulation rates of daughters of closely related sires suggests the presence of a segregating major gene Fecundity Davisdale (FECD) that increases ovulation rate between 0.4 and 0.8 in heterozygous daughters. Key features of mutations in genes of the TGFB superfamily pathway, such as synergistic interactions with other family members, infertility in homozygous carriers, and increased responsiveness to exogenous gonadotropins, were not observed in this line; thus, the mutation does not appear to be acting in the TGFB pathway. Hence, there is likely a novel mutation being carried in this line of sheep that alters ovulation rate. Future identification of the causative mutation may provide new insights into regulation of follicular development and ovulation rate.

There are recognised benefits to managing fisheries by individual transferable quotas (ITQs), but ITQs may increase incentives to discard fish. Trawl data from government-observed trawlers in the New Zealand hoki fishery were used to predict catches of unobserved vessels. These predictions were compared with the catches unobserved vessels reported. Unobserved vessels’ reported catches were significantly different to observed vessels’ catches. There was clear evidence of misreporting in the hoki fishery. Misreporting deprives stakeholders of rentals, distorts catch statistics, and threatens the integrity of ITQ systems. If reporting is similarly biased in other fisheries, the issue cannot be safely ignored.

The parasitoid, Microctonus aethiopoides Loan (Hymenoptera: Braconidae) was introduced into New Zealand in 1982 to control the alfalfa pest, Sitona discoideus Gyllenhal (Coleoptera: Curculionidae). Studies have shown that a number of nontarget weevil species are attacked in the field by this parasitoid. A field study was carried out to investigate nontarget parasitism by M. aethiopoides over an altitudinal sequence from the target host habitat (alfalfa) into native grassland. Three locations were selected for the study, and at each, the alfalfa growing in the valley floor was sampled annually for parasitism of the target pest that ranged between 17 and 78%. At progressively higher altitudes, three further grassland sites at each location were sampled monthly during spring to autumn for up to 6 yr. Weevil densities were estimated, species identified, and dissections carried out to determine reproductive status and parasitism. Almost 12,000 weevils were collected during the study, which were identified as 36 species in total from the three locations. Eight weevil species were found to be parasitized, including S. discoideus, the target host that was found at all sites. Parasitism of nontarget species was approximately 2% overall but varied with location, site, and season. Substantial nontarget parasitism was found at only one of the locations, with up to 24% parasitism of a native weevil, Nicaeana fraudator Broun (Coleoptera: Curculionidae), recorded. Another species, Irenimus egens (Broun) (Coleoptera: Curculionidae), was also found at this location at similar population densities but was attacked far less by M. aethiopoides. Results are discussed in relation to weevil phenology.

Many incomplete block design strategies have been devised to improve the efficiency of experiments. However, the constraints imposed by these designs can be unrealistic because natural blocks may not be all the same size or there may be no conventional designs for required treatment, replication, block and plot combinations. In addition, because of similar constraints, two-dimensional block designs—the so called row-column designs— are used less frequently than the occurrence of conditions where their use would result in greater experimental efficiency. This article explores the properties of an easy to use random generation and selection strategy for obtaining block and row-column designs. Although the strategy does not necessarily obtain the best possible designs when judged by any one of the many criteria, this apparent disad vantage is outweighed by the generality and ease of use. It is concluded that present-day model fitting methods remove the constraints which have been traditionally imposed on designs and the benefits of using block designs can be extended by the use of informal design methods.

The principle cue entraining circannual environmental rhythms and reproductive function in red deer is photoperiod, but other factors probably play important roles in modifying seasonality. Examination of calving records of untreated, first‐calving hinds over a 10‐year period revealed year‐to‐year variation in the mean calving date. Most variation was due to individual hinds, however a significant (P < 0.05) influence of the mean minimum temperature during the early rutting period on calving date was apparent with colder temperatures associated with slightly earlier mean calving dates.

Attainment of puberty is a key developmental event influenced by genetic and environmental factors. In examining age at attainment of puberty, we observed closely related rams from the Davisdale line whose daughters differed in age at which they attained puberty. A candidate gene approach was used to identify mutations that may underlie these observed differences. Four rams with divergent phenotypes for their daughter's age at onset of puberty were selected for whole-genome sequencing. The coding regions of genes with known roles in regulating reproductive function were searched for single-nucleotide polymorphisms (SNPs) that altered the amino acid sequence of the protein. Of interest were three SNPs in the leptin receptor gene (LEPR). A Sequenom assay was developed to determine the genotype of these SNPs in daughters of 17 sons of a founding sire. A higher percentage of ewe lambs homozygous for the LEPR mutations failed to undergo puberty before 1 yr of age, and those that did undergo puberty during the first breeding season on average were approximately 17 days older than homozygous wild-type ewes. Heterozygous ewes were intermediate for both measurements. Given the predicted change in protein function produced by the mutation in LEPR and the strong associations between the genotype and onset of puberty phenotypes, we propose that this mutation in LEPR underlies the observed difference in age at onset of puberty in the Davisdale line. Furthermore, these animals will likely provide a useful model to better understand the role of leptin in the regulation of puberty.

Ginseng (Panax ginseng C.A. Meyer) is a potential new crop for New Zealand. Under artificial shade, 1‐year‐old seedlings were grown in either peat‐ or soil‐based media for 4 years. At the final harvest mean root fresh weight was 55 g/plant in the peat media and 40 g/plant in the soil media. Total ginsenoside % of the 5‐year‐old roots was up to 6.9%. Macrochemical content (N, P, K, S, Mg, Ca) and trace element (Mn, Zn, Cu, Fe, B) content of roots at each harvest and of the leaves at the final harvest, were determined and compared with reported levels for P. ginseng and standards for P. quinquefolius. Botrytis cinerea was present on plant material throughout the experiment, and there was evidence of predation by the scarab larvae of Costelytra novae‐zealandica in the first year. After 4 years of growth, 45% of the plants in the soil media and 63% of plants in the peat‐based media survived.

There has been some recent interest in sequential experiments as a means of reducing the number of animals used in comparative experiments. This paper describes sequential methods and explores their properties. Comparisons are made with fixed sample‐sized experimental designs which result from traditional power calculations. Attention is drawn to potential problems in interpreting and managing sequential experiments and it is concluded that fixed sample‐size experimental designs are still justified on both ethical and financial grounds for comparative experiments, particularly when estimates of the size of the response and their standard errors are important.

The effect of four drill types on the establishment of overdrilled lucerne (Medicago sativa) in a 300–800 mm rainfall tussock grassland environment in New Zealand was examined. The effect of herbicide pre‐treatment and oversowing on plant numbers was also investigated. The highest initial seedling population count was 310 seedlings m−2, but this number declined over three years. All drills established a plant population greater than 56 plants m−2. A prototype roto‐drill gave the highest initial establishment without herbicide because it covered vegetation between coulters and reduced competition, and the triple disc drill had the highest establishment with herbicide. Herbicide pre‐treatment provided higher soil moisture during establishment, increased seedling production, and produced a pure lucerne sward. Lucerne establishment by oversowing was only successful on the herbicide‐treated plots.

Six phosphate rocks (PRs), Sechura (SPR), North Carolina (NCPR), Egypt (EPR), Arad (APR), Zin (ZPR), and Nauru (NPR), were compared with single superphosphate (SSP) as annually applied P fertilisers for mown ryegrass/ white clover swards at two sites, in the central North Island (Te Kuiti) and southern South Island (Woodlands) of New Zealand over a period of three years. NPR was finely ground before application but the other PRs were applied as received and so differed considerably in particle size distribution. Measurements were made of annual dry matter (DM) production and % P in harvested herbage, and Olsen P in the soil at the end of each year. Overall, responses were in the order SSP>SPR∼NCPR>APR∼EPR∼ZPR∼NPR. There were important differences in responsiveness to PRs at the two sites. The agronomic performance of PRs was better related to their extractability by formic acid than to extractability by citric acid. Replacement of the standard citric acid test used in New Zealand by the formic ac...

Introduction of the Inverdale prolificacy gene (FecXI) could markedly improve reproductive efficiency in commercial flocks, but as homozygous carrier Inverdale ewes are infertile, it is imperative that these animals are identified at an early age and excluded from breeding stock. As the ovaries of homozygous carrier ewes are nonfunctional, there are wide differences in reproductive hormone levels between these and other Inverdale genotypes. This study assesses the accuracy of using hormone concentrations alone, to identify infertile homozygous ewe lambs. Ewe lambs were blood sampled at 2, 5 and/or 8 months of age, and plasma analyzed for follicle-stimulating hormone (FSH), luteinizing hormone (LH) and inhibin content. These animals were either the offspring of both known carrier rams and known carrier ewes, and therefore would be either homozygous (II) or heterozygous (I +) for the Inverdale gene (group 1, N = 122), or had one parent that was a carrier and therefore would be either heterozygous or noncarriers (+ +) of the gene (group 2, N = 32). Animals were designated as either II or I + / + + on the basis of their plasma hormone concentrations. Inverdale genotype was also assigned from laparoscopic observation of the ovaries at each of these occasions. Definitive assignment of genotype was made at laparoscopy as adults during the breeding season. On the basis of laparoscopy as adults, 62 (51%) lambs in group 1 were identified as homozygous and 60 (49%) as heterozygous. At all three ages, both mean FSH and mean LH concentrations were significantly higher in II than in I + lambs. Mean inhibin concentrations were significantly lower in II lambs at 8 months, but did not differ significantly between genotypes at 2 or 5 months of age. The use of discriminant analysis techniques to segregate individual animals in group 1 on the basis of their plasma FSH and LH concentrations, correctly identified Inverdale genotype in 50/52 (96%) lambs at 2 months, 75/79 (95%) at 5 months and 118/122 (97%) at 8 months of age. Discriminant analysis was equally effective for segregating II ewe lambs (group 1) from fertile ewe lambs of I + and + + genotype (group 2, 97% correct at 5 months and 98% at 8 months). At no stage did inclusion of inhibin concentrations into the discriminant function alter the number of homozygous ewes misclassified. This demonstrates that infertile homozygous ewe lambs can accurately be distinguished from their fertile flockmates by using plasma concentrations of gonadotrophins alone, and that this can be achieved from as early as 2 months of age.

Forty‐six data‐sets from a series of 17 long‐term field trials measuring the effects of rates and forms of phosphate (P) fertiliser on pasture production and soil fertility in New Zealand were used to characterise the relationship between pasture dry matter (DM) yield in any year (expressed as relative yield, RY) and soil Olsen P test at the end of the annual DM measurement period. Average coefficients of variation in the measurement of these parameters were 7% and 17% for DM yield and Olsen P, respectively. The results failed to demonstrate that the RY at any site in any year could be reliably assessed from a common relationship between RY and the Olsen P test. However, the mean relationship did take the general “diminishing returns” form as expressed by the Mitscherlich equation, and as Olsen P levels increased the probability of low RY decreased. There was no evidence that RY increased with increase in Olsen P test values above 20, with the exception of the one yellow‐brown pumice soil in the ...

Partial neutralization of bone morphogenetic protein 15 (BMP15) bioactivity by immunization is known to increase ovulation rate in sheep. However, it remains uncertain whether BMP15 vaccination would be a suitable procedure for increasing lambing rate. The aim of this study was to compare the efficacy of a BMP15 vaccination treatment on lamb production to that of commercially-available androstenedione-based vaccines that are used for this purpose. Ewes were immunized for 3 yr against androstenedione, BMP15, or no antigen (control). Vaccination with androstenedione or BMP15 altered (P0.05) ovulation rate as well as litter size at midpregnancy, birth, and weaning compared with controls. No differences were detected in the proportions of ewes conceiving in the first cycle or partial failure of multiple ovulations. Both gender and litter size affected birth weight of the lamb (P0.05), but no effect of treatment was found. Growth rate was significantly affected (P0.05) by gender, birth weight, and the number of lambs raised, but not treatment. In conclusion, immunization against either androstenedione or BMP15 increased ovulation rate. Androstenedione vaccination also increased the number of lambs weaned (P0.05). Bone morphogenetic protein 15 vaccination altered the pattern of the number of lambs weaned, but no increase in lamb production was observed as more ewes produced zero or three lambs. Overall, androstenedione or BMP15 vaccination did not significantly affect embryo or fetal survival or lamb performance independently of the effects of these treatments on ovulation rate.

Improvement of depleted grasslands can be restricted by the lack of reliable, cost effective and ecologically sound establishment techniques. This paper presents results from an experimental strip seeder drill designed to mechanically remove competing vegetation. Lucerne ( Medicago sativa L.), birdsfoot trefoil ( Lotus corniculatus L.), cocksfoot ( Dactylis glomerata L.) and tall fescue ( Festuca arundinace Schreb.) were drilled into undeveloped natural grassland with either a triple disc drill or a strip seeder drill in the absence or presence of herbicide. There were small differences between the drills in initial seedling establishment 7 weeks after September sowing but seedling survival over summer varied with drill and herbicide treatment. With the strip seeder drill, 80% and 85% of seedlings survived in the absence and presence of herbicide, respectively, while with the triple disc drill 74% survived in the presence of herbicide but only 40% survived in the absence of herbicide. Five months after sowing, 56% and 63% of the strip seeder furrow was covered by sown species in the absence and presence of herbicide compared with only 6% and 35% of the triple disc furrow. These differences in cover were also reflected in herbage dry matter of sown species in the 3 years following drilling. The results demonstrate the agronomic superiority of the strip seeder drill for establishment of improved pasture species.

The parasitoidsMicroctonus hyperodaeLoan andM. aethiopoidesLoan have been introduced into New Zealand to control the forage pestsListronotus bonariensis(Kuschel) andSitona discoideusGyllenhal, respectively. Laboratory experiments were carried out to investigate the effect of host–parasitoid ratio, and exposure time on host survival, parasitism, oviposition and feeding. Cages of 20 field collected weevils were exposed to 0, 1, 3 or 6 parasitoids for 0, 1, 12 or 48 hours, maintained until parasitoid pupal emergence, and surviving weevils dissected. Over the ranges studied, increasing parasite number, and to a greater extent, period of exposure of parasitoids to their hosts increased parasitism levels.Microctonus aethiopoidesachieved higher levels of parasitism inS. discoideusat the lower parasitoid contact treatments than didM. hyperodaeinL. bonariensis. Fecundity in unparasitized weevils was progressively reduced in bothL. bonariensisandS. discoideusin relation to increasing exposure to parasitoids. Feeding was reduced by about 40% inL. bonariensisfor at least four days after parasitoids were removed, and inS. discoideusfor the duration of the experiment, averaging 15%. Results were discussed in relation to possible mechanisms of indirect effects of parasitoids on unparasitized hosts.

Triple superphosphate (TSP) and Sechura phosphate rock (SPR) were applied to developed pastures annually at 0.75 times the estimated annual pasture maintenance requirement (M) and triennially at 2.25 times M in small‐plot trials at 12 sites for 6 years. A control treatment receiving no phosphorus (P) fertiliser was also included. Pasture dry matter (DM) production and soil Olsen P tests were measured annually at all sites and pasture P concentration at two sites. Total DM production over 6 years did not differ significantly between annual and triennial treatments. Triennial applications resulted in higher DM production in Years 1 and 4, similar production in Years 2 and 5, and lower production in Years 3 and 6, compared with annual applications. Averaged over two 3‐year cycles of fertiliser application, the amplitude of the cyclic effect on DM production from triennial as compared to annual application was + 4% for TSP and ± 2% for SPR. Differences in annual production between triennial and annua...

The possible influence of social factors on the timing of puberty in the hind was investigated utilizing seasonally advanced (melatonin-treated) hinds and stags. Melatonin treatment of both sexes resulted in a significant advancement in the onset of pubertal ovarian activity (26 days, P < 0·001) and calving (27 days, P < 0·001) in the treated hinds and antler casting (25 days, P < 0·001) in the treated stags. Ovarian activity and calving were not influenced by melatonin treatment of the stags alone and similarly, antler casting was not affected by melatonin treatment of the hinds alone. However, a group of hinds without stags until after the onset of the breeding season, reached puberty later (5 days, P < 0·05) than hinds with stags, suggesting the presence of the male is important in determining the timing of puberty.

A national series of rates × forms of phosphate fertilizer trials has provided a large amount of data on patterns of response of pasture production and soil P tests to forms, rates and frequencies of P fertilizer application over time. A simple mechanistic model of P in pastoral systems has been developed in an attempt to account for the observed patterns. The model considers active P in the soil to be in one of two compartments: undissolved fertilizer P (PF) and a pool of labile, plant-available P (PA). P dissolving from PF enters PA, and P is lost from PA by immobilisation in the soil and by net removal above ground through non-recycled uptake by plants. Both these transfers are taken to follow first order kinetics, with rate constants designated K1 and K2 respectively. Pasture dry matter (DM) production in any year is related to the mid-year value of PA by the diminishing-returns Mitscherlich equation, with nil pasture yield being associated with nil PA. Data from different sites with the same design were combined to give generalised response patterns with which to assess the model. Only the control treatment and treatments receiving triple superphosphate (TSP) and Sechura phosphate rock (SPR) were considered. With a value for K1 corresponding to almost immediate dissolution, the model accounted well for the Olsen soil P test patterns from TSP when K2 corresponded to an annual loss of 16.3% of P in PA and a factor of 10 was used to convert Olsen P to kg P/ha in PA. Pasture DM yield response curves to rates of TSP in individual years were well accounted for when the mid-year value of PA required for 90% relative yield was taken as 130 kg P/ha. The model also accounted well for the difference between response patterns to annual and triennial TSP applications for both soil P tests and DM production. The declines in soil P tests and DM production which occurred in nil P controls were less than model predictions: this could be due to unfertilised pasture making more use of P from greater soil depth or less available forms. Olsen P tests with the higher rates of SPR were always lower than model predictions using a value for K1 derived from chemical measurement of SPR dissolution rates in the trials. However, DM yields from SPR were generally close to model predictions. These divergent results support independent data suggesting that available soil P from reactive phosphate rocks (RPRs) is underestimated by the Olsen P test. The relative success of this simple compartmental model in accounting for generalised response patterns in such a large body of data suggests that it could be a useful starting point for a dynamic P fertilizer recommendation model.

The effect of annual applications of triple superphosphate (TSP) and Sechura phosphate rock (SPR) on clover content of permanent pasture was measured at seven sites in New Zealand. Clover content as a percentage of total pasture dry matter (DM) production (% clover) increased with phosphorus (P) application rate, and the response of % clover to P increased with time over 6 years. Most of the response occurred at P fertiliser rates up to the mean calculated maintenance rate of 25 kg P/ha per year, with little further response to twice this rate. The response in total pasture DM production to rate of P fertiliser was similar to the response in % clover. Near‐maximum % clover was achieved with Olsen P levels of 12–15. Percentage clover responses to TSP and SPR did not differ significantly at equal rates of P. There was a significant relationship between % clover and % nitrogen in total DM.

The effects of annual applications at four different rates of either triple superphosphate (TSP) or Sechura phosphate rock (SPR) on the Olsen P test in soil under pasture were measured over 6 years at 13 sites in New Zealand. Averaged over the 13 sites, TSP applied at the calculated maintenance (M) rate maintained an almost constant Olsen P level throughout the 6 years. However, there were marked differences between sites, particularly at the 2.0 M application rate which at some sites raised Olsen P by over 30 μg P/ml soil but caused no increase at other sites. No obvious explanation such as soil group, phosphate retention, rainfall, or pH, or the TSP rates used could be found for these site differences. Olsen P tests were always markedly lower with SPR than with TSP; averaged over the 13 sites, even the 2.0 M SPR treatment barely maintained the initial Olsen P test values. This difference between TSP and SPR in their effect on Olsen P test contrasted with pasture production data (reported elsewh...

Seasonally anovular Coopworth ewes previously isolated from rams were joined with either Coopworth or Poll Dorset entire rams for 28 days from either 6 January or 3 February in each of 3 successive years. Induction of ovulation varied between years, and more ewes ovulated when exposed to rams of either breed in February. When rams were introduced in January, more ewes exposed to Poll Dorset than Coopworth rams ovulated within 28 days of ram introduction. Onset of oestrus also varied between years and treatments. It is concluded that the variation in expression of the ram effect is probably governed by depth of anoestrus of the ewes at the time of joining.

Pasture herbage dry matter (DM) responses to annual applications of triple superphosphate (TSP) at 0.5, 0.75, 1.0, and 2.0 times the calculated maintenance requirement were measured in 12 field trials for 6 years. The trials were on well‐established, permanent pastures which had typical fertiliser histories and represented major pastoral soils of North and South Islands of New Zealand. The DM response to TSP averaged over all rates and sites was 5% in Year 1, increasing to 23% in Year 4 with little change thereafter. At individual sites, average responses in total DM over 6 years ranged from 4 to 24%. Responses increased steadily with time at four sites, but at other sites changes with time were erratic. Mitscherlich curves were fitted to the 6‐year total DM production data for each site. However, the standard errors in the parameters of these fitted curves were very large, making it impossible to predict with any useful degree of accuracy the rate of TSP required for any specified yield. Respons...

Sheep with a heterozygous inactivating mutation in the bone morphogenetic protein 15 (BMP15) gene experience an increased ovulation rate during either a natural oestrous cycle or a cycle in which exogenous FSH and eCG (gonadotrophins) are given to induce multiple ovulations. The primary aim of these studies was to determine whether ewes immunised against BMP15 would also show an improved superovulation rate following exogenous gonadotrophin treatment. A secondary aim was to determine the effects of BMP15 immunisation on ovarian follicular characteristics. In most ewes (i.e. >75%) immunised with a BMP15-keyhole limpet haemocyanin peptide in an oil-based adjuvant in order to completely neutralise BMP15 bioactivity, there was no superovulation response to exogenous gonadotrophins. In ewes treated with exogenous gonadotrophins following a BMP15-BSA peptide immunisation in a water-based adjuvant to partially neutralise BMP15 bioactivity, the ovulation rate response was similar to the control superovulation treatment groups. Characterisation of follicular function revealed that the water-based BMP15-immunised animals had fewer non-atretic follicles 2.5–3.5 or >4.5 mm in diameter compared with controls. Basal concentrations of cAMP were higher in granulosa cells from animals immunised against BMP15 than control animals. There were no significant differences in the concentrations of cAMP between granulosa cells from BMP15- and control-immunised animals when given FSH or hCG, although there were differences in the proportions of follicles in different size classes that responded to FSH or hCG. Thus, immunisation against BMP15 may have been causing premature luteinisation and thereby limiting the numbers of follicles recruited for ovulation following treatment with exogenous gonadotrophins.

Romney ewes grazed red clover (P) or mixed red clover/ryegrass (M) pastures for about 6 months/year until mating in Year 4 (P) or 5 (M) of a 6-year study. A further group grazed ryegrass/ white clover (C) pasture continuously throughout the study. At other times all animals grazed ryegrass/white clover pasture as one mob. Ewes grazing P pasture were consistently 3–6 kg heavier than ewes that grazed C pasture. Despite similar proportions of ewes being marked by the ram, and similar ovulation rates, during the first cycle of mating each year, ewes grazing P pastures consistently showed increased returns to service (+30%), increased barrenness (+30%), and fewer lambs born per ewe joined (-0.5) than ewes grazing C pasture. Differences persisted after ewes were removed from treatment pastures, indicating that infertility was likely to be permanent.

The practice of doing a single comparative trial at a particular site and extrapolating results from that site to many others, ignores the potential variability in results which may occur when the same treatments are applied in different environments. In order to overcome this difficulty with on-farm investigative developments, the concept has been extended. Single replicates of simple experiments at many sites are proposed as a method for the agronomic evaluation of plants, fertilisers, and weed or pest control strategies. It is concluded that this extension will allow more general conclusions and more widespread technology transfer to take place.

Soil pH was measured over 6 years in 10 field trials in which superphosphates (SPs) and reactive phosphate rocks (RPRs) were applied annually to clover/grass pastures at rates equivalent to 0, 0.5, 0,75, 1.0, and 2.0 times the estimated amounts of phosphorus (P) required for maintaining near-maximum pasture production. Over the 6-year period, soil pH (0–75 mm soil depth) fell by an average of 0.16 units in control and SP treatments with no significant effect from rate of SP application. RPRs reduced the fall in pH and this effect increased with increasing RPR application rate, the fall in pH being virtually eliminated by the highest RPR application rate. The effect of RPRs on reducing the fall in soil pH could be largely accounted for by the difference in phosphate protonation compared with SPs, and the carbonate content of the RPRs.

Ram lambs were selected from a total of 1206 lambs in 8 industry Coopworth ram breeding flocks. Eight rams were selected randomly (one from each flock), 8 were selected on the basis of a low live weight-adjusted ultrasonic backfat thickness (lean) and 8 for a high post-weaning growth rate (PW gain). Rams from a Coopworth line specially selected and bred for low ultrasonic backfat (lean selection) were also included in the progeny test in which the rams were single sire mated to 1.5 year old Coopworth ewes. Birth and weaning weights were recorded for a total of 474 female and 371 male progeny. The males (progeny of 31 sires) were slaughtered between January and April at an average hot carcass weight (HCW) of 12.56 kg and carcass growth and carcass fatness parameters recorded. The carcass composition data were analysed using the allometric equation by covariance on HCW. The adjusted mean values of carcass water content were significantly higher for the progeny of the lean selection rams (7.58 kg) than forthe other 3 sire classes (7.49, 7.46 and 7.41 for the lean, PW gain and controls respectively) indicating that they were leaner. Other indicators of carcass fatness also revealed marked differences between the sire classes. There were also marked effects of slaughter date with lambs slaughtered earlier being leaner (after adjustment for HCW) than lambs slaughtered later in the season. The results indicate that selection of sires on the basis of ultrasonic backfat thickness or post weaning live weight gain can be expected to result in the production of leaner lamb carcasses.

Reactive phosphate rocks (RPRs) from Sechura, Peru (SPR) and North Carolina, USA (NCPR) were compared with triple superphosphate (TSP) as phosphate (P) fertilizers for permanent grass/clover pastures in four field trials in New Zealand. Trial sites ranged in initial pH (in water) from 5.7 to 6.3 and in rainfall from 712 to 1338 mm yr−1. SPR and NCPR were used in the unground ‘as-received’ state. Fertilizers were applied annually for six years. Pasture was harvested by frequent mowing, and herbage dry matter (DM) yields were measured at each cut. Herbage P concentrations were measured at each cut in two trials and on most cuts in the other two. For all sites combined, DM production from RPRs was initially significantly less than from TSP but it improved relative to TSP with time. Substitution values of RPR relative to TSP, denoted by S.V. (TSP/RPR) and defined as the ratio of P in TSP to P in RPR required to produce the same plant response during a specified period of time, were estimated by relating yields from RPR treatments to the yield response curve for different application rates of TSP. For the four trials combined, S.V. (TSP/SPR) increased from 0.32 in year 2 to 0.85 in year 6. S.V. values for NCPR were similar. The site which had the lowest S.V. values (average 0.20) for total production over six years was the site with highest pH (6.3) and lowest rainfall (712 mm). Corresponding S.V. values for the other sites were 0.50 to 0.78. Herbage P concentrations showed a similar pattern of RPR performance relative to TSP to that shown by DM production except at the highest application rate where TSP always supported much higher herbage P concentrations than RPR. The pattern of DM production from RPR relative to TSP was explained on the basis of a model involving soil P pools of undissolved fertilizer P and plant-available P respectively, with the hypothesis that P dissolved from RPR entered the plant-available P pool and was used with the same efficiency as P entering by dissolution of TSP. Model predictions of substitution values using directly measured RPR dissolution rates agreed well with observed substitution values. The advantage of RPRs in comparison to soluble P fertilizers for permanent pastures was considered to lie in their lower price and not in greater nutrient efficiency. Economic advantage was calculated in terms of the return on investment from establishing and maintaining a pool of RPR in the soil large enough to release the required annual amount of plant-available P compared with the cost of annual applications of soluble P fertilizer.

The five fattest and five leanest rams were selected on the basis of their liveweight-adjusted ultrasonic backfat thickness from a flock of 100 Coopworths at around 6 months of age. A total of 110 male progeny of these 10 rams were slaughtered between January and April at a mean hot carcass weight (HCW) of 17.13 kg. There were no significant differences between sire classes (i.e., lean, fat) in the weights of the progeny (HCW of 16.95 and 17.31 kg, SED ±0.621). However, there were very marked differences in the regression slopes for the allometric relationships between several carcass variables and HCW, with the lean class having significantly lower slopes for carcass chemical fat content and three subcutaneous fat depths than the fat class. The estimated heritability for backfat thickness (progeny-sire regression) was 0.25. The results indicate that significant progress in terms of carcass leanness should be achievable through the use of suitable ultrasonic devices for measuring backfat thicknes...

A trial was carried out in unimproved tussock grassland on the East Otago Plateau of the South Island of New Zealand to investigate the impact of native broad-nosed weevils (Coleoptera: Curculionidae) feeding on survival, establishment, and yield of oversown white clover. The trial consisted of 20 sites 1 km apart where two plots were established in each of 5 consecutive years. At each of the sites in each year, one of the plots was sprayed with parathion at 2-weekly intervals from September to December to allow seedlings to establish in “insect-free” conditions. The other plot was left untreated. The plots were sown in October and, by late December, seedlings suffered on average 40 and 6% mortality in the untreated and sprayed plots respectively. Sublethal insect feeding reduced nodulation on average by 46% and final established plant density by 39% in the unsprayed plots. Despite identical treatment of the two plots after the initial 3 months, white clover yields were significantly higher in th...

In a series of 12 field uials located throughout New Zealand annual application of phosphate(P) fertiliser was compared with ttiennial application using rates which applied the same total amount of P over 6 years. Test materials were triple supetphosphate (TSP) and Sechura phosphate rock (SPR), both of which were applied annually at rates which provided 0.75 times the calculated maintenance P requirement (0.75 M) and triennially at 2.25 M.For the 12 sites combined there was a significant response to P fertiliser each year. Application frequency had no significant effect on total DM yield over the 6 year period with either TSP or SPR. A cyclic effect with triennial applications was appsrent for both fertllisers, with approximately 2-4% higher yields in the first year and 2-4% lower yields in the third year of both 3 year cycles. These results indicate that on well developed pastures a change from annual to triennial application frequency of phosphate fertillser, with either TSP or slow release SPR, will have little effect on DM production providing the same total amount of P is applied. This gives farmers the opportunity to make some adjustment to P fertiliser application frequency according to fluctuations in availability of finance. However, these conclusions do not apply to other nutrients such as sulphur, potassium and trace elements for which annual applications may he necessary. Keywords triple superphosphate, Sechura phosphate rock, phosphate fertilisers, annual application, triennial application, application frequency, reactive phosphate reck

Proliferation of new phosphatic fertilizers with diverse chemical properties necessitates much agronomic evaluation including comparison in field experiments. If such experiments lack the power to detect real and economically important differences between fertilizers, there is a danger of inferior products entering the fertilizer market. The ability of field experiments to detect differences in plant yield from different fertilizers depends not only on the intrinsic differences between fertilizers but also on site responsiveness to phosphate, experimental variability and degree of replication. Biometrical guidelines are provided to assist in the design of powerful field experiments and a formula is developed for determining the replication required to detect differences in specific situations. The number of replications required to have a high probability of detecting important differences between phosphatic fertilizers is more than sometimes used. It is concluded that extreme reserve is necessary in interpreting trial results which fail to show a significant difference between materials.

Establishment of grasses and legumes drilled in spring with a prototype strip seeder drill or a conventional tripledisc drill werecomparedon two sites in the presence and absence of paraquat. On theE%rnscleughsite,plantestablishmentinautumn, as a percentage of viable seed sown, was higher with the prototype drill than with the triple disc drill in the absence of paraquat. The application of paraquat increased establishment with the triple disc drill and differences between the drills were not consistent over species. Paraquat had no discernible effect on the competing vegetation or establishment at Ohau Downs. Establishment of birdsfoot trefoil, cocksfoot and tall fescue, but not alsike clover, was significantly higher in autumn in the prototype drill treatment. Treatment effects on standing herbage mass on both sites followed a similar trend to establishment although paraquat increased herbage mass in the prototype drill treatments on Eamscleugh, in contrast to the nonsignificant effect on establishment. The present results indicate the potential of the prototype strip seeder drill for cost effective establishment of improved pasture species in difficult environments. Keywords direct drilling, establishment, strip seeder, luceme, tall fescue, birdsfoot trefoil, upland brome,alsike clover,cocksfoot,paraquat, herbicide

The concurrent and long-term effects of feeding high (H) and low (L) levels of nutrition from weaning to 4 years of age were measured in 188 high fecundity heterozygous Booroola Merino × Coopworth (BC) ewes (FecB Fec+) and 58 low fecundity New Zealand Merino × Coopworth (MC) ewes. Following the cessation of differential feeding, all groups were grazed on a common plane of nutrition for 2 years. There were no significant nutrition by genotype interactions for liveweight, lamb performance, or ewe lambing performance. During common feeding, carryover effects of restricted feeding were apparent only for liveweight and barrenness. The mature liveweight of H ewes was 60–70 kg throughout differential feeding, which was 12–15 kg heavier than L ewes. L ewes showed 58% compensatory growth but were still 5.1 kg lighter than H ewes (P < 0.05) at the end of the experiment. Ovulation rates of L ewes were 0.07–0.51 lower than their H contemporaries during differential feeding and this was significant (P < 0.05 ...

A series of laboratory experiments was carried out with the main objective of contributing to the development of biosafety testing methods for transgenic plants or plants produced by other novel technologies. The adult stage of a New Zealand native weevil, Nicaeana cervina (Broun) (Coleoptera: Curculionidae: Entiminae), was used as a test insect as this has become well-adapted to introduced pasture species, feeding on both ryegrass [Lolium perenne L. (Poaceae)] and white clover [Trifolium repens L. (Fabaceae)]. Ryegrass plants used in experiments were infected with strains of the symbiotic endophytic fungi Neotyphodium lolii (Latch, M.J. Chr. & Samuels) and Epichloe festucae Leuchtm., Schardl & M.R. Siegel and included a transgenic endophyte, which was modified to eliminate production of the insect deterrent, peramine. Nicaeana cervina was exposed to these endophyte-infected plants along with endophyte-free ryegrass. Weevils were also exposed to white clover with high or low levels of cyanogens, and to white clover selections bred conventionally to contain high or low levels of crude protein. These bioassays were carried out sometimes over a series of time intervals, and weevil survival, feeding, and reproductive performance variables were measured. Nicaeana cervina survival was generally high, although feeding and oviposition were variable between experiments despite high replication in some cases. A summary of significant differences obtained across all experiments suggested that data on the proportion of weevils feeding and amounts of leaf material consumed were more often significantly different than treatment effects on survival or reproductive performance. A positive relationship between the proportion of weevils feeding and those ovipositing was found, suggesting that a 50% reduction in feeding would result in a 28% reduction in the proportion of weevils ovipositing. Power analysis using the range of values recorded for the variables measured indicated that for proportions of weevils surviving, feeding, or fecund, about 35-42 replicates would be required for a 40% difference in values. For measures of leaf consumption and numbers of eggs per female, fewer replicates were required for 95% power when these values were at the higher end of the range than when they were at the lower end of the observed range. The usefulness of the case study test insect and risk assessment protocols used for biosafety testing are discussed.

The aim of this study was to determine if single nucleotide polymorphisms (SNPs) in the leptin receptor (LEPR) gene associated with delayed onset of puberty are associated with changes in other reproductive traits in adult ewes. The ovulation rate of ewes homozygous for the SNPs was ~15% lower (P

In a series of experiments, involving 372 lambs over 2 years, the effects of subcutaneous implants of Cimaterol (CL263, 780; anthranilonitrile, 5-[1-hydroxy-2-(isoproplyamino)ethyl]-), in young sheep grazing pasture were examined. Treatment with Cimaterol increased carcass weight gain by 37% averaged over the experiments. Wool growth was reduced by 16% in the experiments where it was measured. Cimaterol treatment also increased dressing percentages by 1.3-3.7 percentage units, increased the cross-sectional area of L. dorsi muscle, and decreased fat depot weights and subcutaneous fat thickness measurements in all experiments. These changes were accompanied by increased protein and water contents and a decreased fat content in the carcass. Analysis of the growth rates of carcass components revealed that the changes were a consequence of marked increases in the rates of carcass protein deposition (up to c. 3-fold) in Cimaterol-treated lambs accompanied by markedly reduced rates of lipid deposition. ...

Motivation: Microarray experiments with thousands of genes on a slide and multiple slides used in any experimental set represent a large body of data with many sources of variation. The identification of such sources of variation within microarray experimental sets is critical for correct deciphering of desired gene expression differences. Results: We describe new methods for the normalization using spatial mixed models which include splines and analysis of two-colour spotted microarrays for within slide variation and for a series of slides. The model typically explains 45–85% of the variation on a slide with only ∼1% of the total degrees of freedom. The results from our methods compare favourably with those from intensity dependent normalization loess methods where we accounted for twice as much uncontrolled and unwanted variation on the slides. We have also developed an index for each EST that combines the various measures of the differential response into a single value that researchers can use to rapidly assess the genes of interest. Availability: GenStat code is available from the first author.