Medial claws from the right hind feet were obtained post mortem from four 19–20-month-old beef heifers and from four 28-month-old first-calving dairy heifers 3–4 days postpartum. X-ray diffraction (XRD) studies were undertaken on samples of soft and hard (cornified) integumental tissues of dorsal wall, sole and heel (bulb) for varying sites and planes of exposure. The measurements were interpreted as defining diffraction patterns and intermolecular spacings of cytoskeletal and extracellular fibrous structural proteins. The orientation of these proteins was examined in relation to physical characteristics and function including bearing of body weight by these tissues.

Physical measurements taken included impression hardness which showed typically greater values for wall than sole and variable differences between horn of dairy and beef origin and husbandry systems. Claws from dairy heifers had significantly smaller values for toe (dorsal wall) angle, claw height and heel height and thickness of solear horn and heel soft tissue. Although few were studied, the results reflected typical husbandry origins and indicated the susceptibility to the lesion formation well recognized in postpartum dairy cattle.

Typical XRD patterns for horn samples showed defined arcs of reflectance on the equatorial axis consistent with findings for the presence of α-helices in fibrils reported to occur in other hard-keratin-containing integumental tissues. However, reflectance on the meridional axis also reported for these other tissues was not detected. A similar defined pattern was obtained for less than 0·10 of samples of internal soft pre-cornified epidermal and attached dermal tissue although the values for intermolecular ‘d’ spacing for these were consistent with those reported for type I collagen. Diffuse reflection patterns were thus evident for the majority of samples of soft tissue epidermis and dermis and also for adipose tissue of the digital cushion.

The formation of defined arcs of reflectance allowed the determination of fibril alignment in wall and solear horn. For the orientated samples of dorsal wall horn tissue, the outer layer showed a longitudinal angle of orientation essentially maintained proximal to distal. This pattern was maintained throughout the depth of horn at the proximal site. In contrast, layers in mid-wall and towards the distal edge showed a greater circumferential (horizontal) orientation in sections collected anterior to posterior towards the inner corial, including laminar, tissues. The orientation of fibrils in inner wall horn appears to relate to the direction of load-bearing forces in connecting horn to the distal phalanx. Horizontal alignment of fibrils was observed in the sole. In presenting the long axis of cells to the ground surface this orientation may facilitate erosive forces and contribute to the thinning of cornified sole horn under adverse underfoot conditions.

The present paper explores the ‘farmer’ effect in economic advantages often claimed for Bt cotton varieties (those with the endotoxin gene from Bacillus thuringiensis conferring resistance to some insect pests) compared to non-Bt varieties. Critics claim that much of the yield advantage of Bt cotton could be due to the fact that farmers adopting the technology are in a better position to provide inputs and management and so much of any claimed Bt advantage is an artefact rather than reflecting a real advantage of the variety per se. The present paper provides an in-depth analysis of 63 non-adopting and 94 adopting households of Bt cotton in Jalgaon, Maharashtra State, India, spanning the seasons 2002 and 2003. Results suggest that Bt adopters are indeed different from non-adopters in a number of ways. Adopters appear to specialize more on cotton (at least in terms of the land area they devote to the crop), spend more money on irrigation and grow well-performing non-Bt varieties of cotton (Bunny). Taking gross margin as the basis for comparison, Bt plots had 2·5 times the gross margin of non-Bt plots in both seasons. If only adopters are considered then the gross margin advantage of Bt plots reduces to 1·6 times that of non-Bt plots. This is still a significant advantage and could well explain the popularity of Bt in Maharashtra. However, it is clear that great care needs to be taken with such comparative studies.

Decision-making processes in agriculture often require reliable crop response models. The Fujian province of China is a mountainous region where weather aberrations such as typhoons, floods and droughts threaten rice production. Agricultural management specialists need simple and accurate estimation techniques to predict rice yields in the planning process. The objectives of the present study were to: (1) investigate whether artificial neural network (ANN) models could effectively predict Fujian rice yield for typical climatic conditions of the mountainous region, (2) evaluate ANN model performance relative to variations of developmental parameters and (3) compare the effectiveness of multiple linear regression models with ANN models. Models were developed using historical yield data at multiple locations throughout Fujian. Field-specific rainfall data and the weather variables (daily sunshine hours, daily solar radiation, daily temperature sum and daily wind speed) were used for each location. Adjusting ANN parameters such as learning rate and number of hidden nodes affected the accuracy of rice yield predictions. Optimal learning rates were between 0·71 and 0·90. Smaller data sets required fewer hidden nodes and lower learning rates in model optimization. ANN models consistently produced more accurate yield predictions than regression models. ANN rice grain yield models for Fujian resulted in R2 and RMSE of 0·87 and 891 vs 0·52 and 1977 for linear regression, respectively. Although more time consuming to develop than multiple linear regression models, ANN models proved to be superior for accurately predicting rice yields under typical Fujian climatic conditions.

The development of the genetic control of nematode resistance in growing lambs is of biological interest, as well as being important in terms of designing practical strategies to breed for increased nematode resistance. The current paper demonstrates the use of random regression techniques for quantifying the development of the heritability of faecal egg count (Fec), the indicator of nematode resistance, in growing lambs and predicted inter-age genetic and phenotypic correlations for Fec. Fec data from 732 lambs, collected at 4-week intervals from c. 8–24 weeks of age, were analysed using random regression techniques. Random effects fitted in the model included genetic, individual animal environmental, litter and residual random effects. Output (co)variance components were interpolated to weekly time points. Individual variance components showed complex patterns of change over time; however, the estimated heritability increased smoothly with age, from 0·10 to 0·38, and showed more stable time trends than were obtained from univariate analyses of Fec at individual time points. Inter-age correlations decreased as the time interval between measurements increased. Genetic correlations were always positive, with 0·6 of all possible inter-age correlations being greater than 0·80. Phenotypic correlations were lower, and decreased more quickly as the time interval between measurements increased. The results presented confirm biological understanding of the development of immunity to nematode infections in growing lambs. Additionally, they provide a tool to determine optimal sampling ages when assessing lambs' relative resistance to nematode infections.

Animal manures are a valuable resource, providing readily available plant nutrients; however, runoff from lands receiving animal manure has been shown to contribute to water pollution. Understanding the loss of nutrients from slow release fertilizers, such as animal manure, after application is critical in determining and designing practices to reduce and/or control the temporal availability and potential offsite transport of NO3-N and NH4-N after application. A block study was designed to compare and contrast the temporal losses of NO3-N and NH4-N from three slow release fertilizers (sulphur-coated urea, composted dairy manure, and poultry litter) and one fast release fertilizer (ammonium nitrate) applied to bermudagrass (Cynodon dactylon L. Pers.) turf. Cumulative NO3-N loss from plots receiving application of the manufactured (NH4NO3 and sulphur-coated urea) products was significantly (P<0·05) greater than the measured losses from plots receiving application of natural products (composted dairy manure and poultry litter). The cumulative NO3-N recovered in the runoff expressed as a proportion of applied N was 0·37 for ammonium nitrate, 0·25 for sulphur-coated urea, 0·10 for composted dairy manure, and 0·07 for poultry litter during the 10-week study period. Cumulative NH4-N recovery fractions were an order of magnitude less than the cumulative NO3-N fractions and no significant differences (P>0·05) were measured across treatments. Significant differences (P<0·05) in NH4-N and NO3-N loss through time were measured for the four treatments. The findings of the present study indicate that land-applied animal manures are less susceptible to initial losses of N when compared to manufactured fertilizers.

Intensive agricultural production practices are known to cause far-reaching effects on water quality. The current paper addresses and quantifies these effects caused by high stocking rates.

A set of stochastic difference equations describing the development of the proportion of a grazed field either unaffected by urine deposition, or affected by multiple (1, 2, …) urine depositions is described. A solution to this set of equations is found for the expected value of multiple (0, 1, 2, …) urine depositions, and the variances of these depositions. It is assumed that an animal voids urine with a Poisson probability distribution, and that each urine deposition covers a random area with a Gaussian probability density. Given these reasonable assumptions, the probability distributions for each multiplicity of patch distribution can be found numerically.

The utility of the results obtained is illustrated for a problem in assessing the nitrogen (N) pollution of ground water from different grazing strategies. It is demonstrated quantitatively that mob stocking (typical of winter management regimes in New Zealand) is often caused by rotational grazing. The latter is often used to optimize grass growth and intake, especially in winter. This increases (more than linearly) the level of N pollution in ground water. This is because of the increased frequency of multiple urine depositions, i.e. more than one urine deposition on the same patch of land in a short time.

This group, which is concerned with the applications of mathematics to agricultural science, was formed in 1970 and has since met at approximately yearly intervals in London for one-day meetings. The thirty-ninth meeting of the group, chaired by Professor N. Crout of the University of Nottingham, was held in the Kohn Centre at the Royal Society, 6 Carlton House Terrace, London on Friday, 30 March 2007 when the following papers were read.

The purpose of the current work was to study phosphorus (P) metabolism in growing sheep supplemented with different levels of dicalcium phosphate using an extant mathematical model. Twelve male non-castrated Santa Inês sheep, weighing 23 (±2·2) kg, received a basal diet unsupplemented or supplemented with dicalcium phosphate to provide 1·5, 3·0, 4·5 g of P/animal per day (treatments T1 to T4, respectively). After 3 weeks adaptation, 7·4 MBq of 32P was injected into the jugular vein of each animal. Samples of blood, faeces and urine were collected every day during a 7-day period and thereafter the animals were sacrificed and samples from liver, kidney, heart, muscle and bone were collected for specific activity and inorganic P determinations. The flows between gut and plasma were similar for each treatment except for T1, which showed the lowest values for both flows (P<0·05). The amount of P accreted to soft tissue (F42) was different among treatments, however net tissue retention was similar for all treatments. Total P retained was highest for T4 and lowest as well as negative for T1 and T2. Phosphorus accreted to bone (F32) was different among treatments and contributed to the different net bone retentions. The highest value of F32 was reached by animals on T4, whilst the lowest values were found for animals on T1. Despite having the highest value of F32, it should be noted that animals on T4 excreted the most P in faeces. Considering concerns about environmental P pollution, it is important to be aware that the treatment which provided the highest value for net bone P retention and for F42 also led to the highest value of P excreted in faeces. Therefore, the current study suggests that T3 provided the best P level for this category of animal since P accreted to bone and tissue indicated that P absorption was adequate to attend to P requirements.

An understanding of genotype by environment (G×E) interaction would be useful for establishing breeding objectives, identifying the best test conditions, and finding areas of optimal cultivar adaptation. Data from field assays including eight environments and eight elite lines were analysed to identify environmental and genotypic variables related with G×E interaction for yield in sesame multi-environment trials in Venezuela. Both predictable and unpredictable environmental variables were recorded. Yield components were recorded as genotypic variables. Yield and yield components were used to perform additive main effect and multiplicative interaction (AMMI) analysis. Significant differences (P<0·01) for G×E interaction were observed for all variables examined, except for the number of branches per plant. For yield, 0·28 of the total sum of squares corresponded to G×E interaction. Using environmental and genotypic data, correlation analysis was carried out between genotypic and environmental scores of the first interaction principal component axis (IPCA 1) for all variables examined. Significant correlations (P<0·05) were observed between IPCA 1 for yield and content of sand and silt in soil. No significant correlation was found between IPCA 1 score for yield and genotypic variables. These results indicate that edaphic properties at the trial locations play an important role in yield G×E interaction in Venezuelan sesame. These results should help select test sites for sesame in Venezuela to minimize G×E interaction and make selection of superior genotypes easier. Two strategies can be recommended: multi-environment trials at sites with average, not extreme, sand and silt content, or stratification of sites according to sand and silt content.

Alkanes can be used as natural markers for estimating diet composition, but a factor should be used to correct for incomplete recovery in faeces. Faecal alkane recovery rates may be influenced by diet and animal factors. However, little research has been conducted to evaluate the effects of herbage species and live weight of animals on faecal alkane recoveries. In the current study, faecal recoveries of alkanes were determined in sheep in four different live weight groups (from 20 to 40 kg) fed three plant species (Elymus sibiricum, Leymus chinensis and L. dasystachys). In a second experiment, the accuracy of intake and diet composition estimates, using alkanes as faecal markers, was assessed by feeding known amounts of the same plant species as a three-component mixture. The results showed that faecal alkane recoveries were influenced significantly by herbage species (P<0·01), but no effect of live weight of animals was observed. Total dry matter intake was estimated correctly based on either C31:C32 or C29:C32 alkane pairs. With respect to estimators of E. sibiricum intake, reasonable results could only be obtained if the faecal alkane concentration was corrected based on diet-specific faecal recovery. More accurate estimations were obtained only if the alkanes found in relatively higher concentrations were used in diet composition estimates instead of using all available alkanes. Due to lower alkane concentrations or similar alkane patterns of L. chinensis and L. dasystachys in the diet, estimates of diet composition of these two herbage species were significantly different from the actual ones (P<0·05), implying that other markers need to be used for accurate estimation.

Fifteen indigenous nondescript kids (8·2 kg; 8 months initial age), randomly allotted into three equal groups, were used to study the effects of supplementation of extra iodine on their performance when fed a leucaena (Leucaena leucocephala) leaf meal containing diet. Group I (CON) was fed a control concentrate supplement consisting of a conventional protein source whereas the other two groups (LL and LLI) were fed a concentrate containing leucaena leaf meal so as to supply 0·5 of the net crude protein (CP) requirements. Additionally, animals in group LLI were given supplemental iodine (as potassium iodide solution) at 0·25 mg/head/day. Wheat straw was provided ad libitum as the sole source of roughage during the 120 days of the experimental period. A metabolism trial, conducted at the end of the feeding trial, revealed no variation in the dry matter intake (DMI) among the groups. A significant (P<0·01) decline was evident in digestibility of CP in both the leucaena-fed groups (0·463 and 0·482 versus 0·586) whilst that of the other organic components remained unaffected. Animals on the LL diet exhibited lower (P<0·01) nitrogen retention and average daily gain (ADG) in live weight (LW). Blood collected periodically was analysed for the thyroid hormones triiodothyronine (T3) and thyroxine (T4) as well as other biochemical parameters. At the end of the experimental feeding, the cell-mediated immune (CMI) response of the goats was assessed by intra-dermal inoculation of phytohaemagglutinin-P and measuring the change in skin thickness at various post-inoculation hours. The results revealed that the serum concentration of glucose was significantly (P<0·05) higher in the LLI group of animals fed leucaena with iodine. The concentration of cholesterol in serum of LL animals increased significantly (P<0·05) compared to the CON and LLI groups. No variation due to dietary interventions was evident in other indices of metabolic profile. While the concentration of circulating T3 remained unaffected due to dietary intervention, that of T4 reduced significantly (P<0·05) in the LL group. Moreover, the T4 concentration in the LLI group remained similar to that of control indicative of positive impact of iodine supplementation. The immune response revealed that the skin thickness of animals in the LL group was lower (P<0·05) as compared to the control, indicating a compromise of CMI response due to feeding of leucaena leaf meal. Supplementation of iodine appeared to be partially effective in potentiating the response. In conclusion, iodine supplementation could be adopted as a strategic management strategy to ameliorate the negative impacts of feeding leucaena leaf meal in growing kids.

Four Karan/Friesian crossbred (Holstein×Tharparkar) dairy cows in late lactation (>200 days) were fed a basic diet of green maize and concentrates with an increasing proportion of Leucaena leucocephala (leucaena) leaf meal (LLM). The proportion was gradually increased from 0·25 of the dry matter intake (DMI) in the first week to 0·50 in the second, 0·75 in the third and ad libitum in the fourth week. Mimosine, 3,4-dihydroxy pyridine (3,4-DHP) and 2,3-dihydroxy pyridone (2,3-DHP) levels were determined in milk, serum, urine and faecal samples. On average DMI of leucaena was 0·023–0·025, 0·025–0·027, 0·027–0·028 and 0·022–0·025 of live weight (LW) during the first, second, third and fourth week, respectively. Mimosine, 3,4-DHP and 2,3-DHP appeared in the blood serum during leucaena feeding and continued appearing up to sixth week of experimental feeding even after the withdrawal of leucaena from the 34th day onwards. Similarly, excretion of mimosine, 3,4-DHP and 2,3-DHP were observed even after withdrawal of leucaena from the diet. The feeding of LLM resulted in a reduced level of T3 (Triiodothyronine) and T4 (Thyroxine) within a week of LLM feeding. The level of T3 and T4 improved to normal after withdrawal of LLM from the diet. The serum aspartate transferase (AST) and serum alanine transferase (ALT) activities were within the normal range. Leucaena feeding improved milk yield and composition only up to 3 weeks of feeding. The concentration of mimosine, 3,4-DHP and 2,3-DHP in milk was 0·33, 0·05 and 0·02 that of blood, respectively. The secretion of mimosine, 3,4-DHP and 2,3-DHP in the milk might be a concern for health of the offspring of leucaena-fed animals as well as human beings consuming such milk.

The estimation of dry matter intake (DMI) using the alkane pair technique has been validated in ruminants, but not in equids. The current paper reports the finding of three comparative validation studies carried out using a total of 12 cattle, 29 donkeys and 10 horses during which directly measured intake was compared to estimated intake using the alkane pair technique. Two methods were developed to dose the even chain alkanes that were used as external markers. Study I, carried out in Zimbabwe, compared the accuracy of estimated intake with measured intake in cattle and donkeys using hexatriacontane (C36) as the external marker. Studies II and III were carried out in the UK with horses and donkeys and compared the accuracy of estimated intake with measured intake using dotriacontane (C32) as the external marker. Study III also tested the effect on the accuracy of intake estimates of two marker dosing levels (mean daily dose of 224 mg per animal and 448 mg per animal) and two dosing frequencies (2× and 3× daily). Twice daily dosing of even-chain alkane at the lower dose level provided an estimate of DMI similar to that obtained by thrice daily dosing at this low level. The higher dose level given twice daily tended to produce large variation in faecal concentrations of dosed even-chain alkanes, this variation was reduced when dosing frequency was increased to thrice daily. The accuracy of estimated intake improved progressively as the number of faecal sampling days was increased from one to six with no significant difference between estimated intake based on day 5 or 6 of faecal sampling.

The results of all three studies indicate that the alkane pair technique provides a robust method of estimating intake in equids with no significant difference between measured and estimated values in all but one case. Using C31 as an internal marker provided a more accurate estimated intake than using C33 as the internal marker in all cases. Faecal recoveries of alkanes in equids do not appear to show the same influence of carbon chain length that has been observed in ruminant studies.

The current paper presents information from a survey of the practices associated with the control of ectoparasites on sheep in Northern Ireland in 2005, including the estimated total quantities of pesticide active ingredients used. It also provides comparative data to that obtained from previous surveys in 1981 (Jess & Marks 1986), 1988 (Foy et al.1995) and 1997 (Jess et al.2000). The total number of sheep farms in Northern Ireland decreased by 25% to 8822 farms with a consequent 26% reduction in total sheep population to 2·1 million sheep compared with the previous survey in 1997. During this period, the number of sheep treated for ectoparasites decreased by 40%. The total quantity of organophosphorus (OP) compounds used for ectoparasite control decreased by approximately 67%, from 7·8 tonnes in 1997 to 2·6 tonnes in 2005, during which an estimated 0·38 of all sheep treated for ectoparasites received the OP active ingredient diazinon. The survey results indicate a decline in the practice of plunge-dipping sheep for ectoparasite control with the proportion of farms using this treatment method decreasing from 0·58 to 0·16 between 1997 and 2005. In 1997, an estimated 0·8 of all sheep treated for ectoparasites in Northern Ireland were plunge-dipped, which reduced significantly to 0·28 during 2005. Conversely, the use of alternative methods has increased with pour-on formulations of insecticides, macrocyclic lactones and growth regulators being applied to 0·33 of all sheep treated in 2005 compared with 0·09 in 1997. Use of intramuscular or subcutaneous injections of macrocyclic lactones for ectoparasite control has also increased to 0·24 of all sheep treated in 2005 compared with 0·1 in 1997. The proportion of sheep treated in communal spray showers also increased from 0·01 in 1997 to 0·14 in 2005. Control of blowfly maggots (Lucilia spp.) and prevention of sheep scab (Psoroptes ovis) were the main reasons given by farmers for sheep treatments. On the farms that plunge-dipped, an estimated 0·68 of surplus dip wash was disposed of immediately after dipping took place, with 0·8 of farms emptying the dipping tanks using a vacuum tanker and 0·54 spreading the surplus dip wash directly onto land. An estimated 0·35 of these farmers mixed the dip wash with slurry pre-disposal. The survey suggests that the products used for spray showers are those recommended for plunge-dipping as there are no contemporary products recommended for use in spray showers. Macrocyclic lactone injections recorded in the survey had the dual function of controlling both endo- and ectoparasites.

The physical properties of hardness and dry matter and the histological characteristics of dermal and epidermal tissues were investigated in lateral and medial claws obtained post mortem from mature crossbred female cattle. Claws containing pigmented (n=22) or non-pigmented (n=22) coronary wall horn were studied. Impression hardness, measured on the dorsal border of claws, proximo-distal at intervals of 5 mm from the lower perioplic line was shown to increase to the 20 mm lower site. Similarly, in comparison with values for pigmented horn, pooled measurements for non-pigmented horn showed greater hardness from the lower perioplic line to the 40 mm lower site but were not different for subsequent measurements towards the distal edge. Differences in values recorded for sole and heel and for coronary wall horn measured under the distal edge were not different for claws varying in coronary horn pigmentation. The absence of differences in dry matter at measurement sites suggested that differences in impression hardness values were not caused by variation in water content of horn. Histological examination of pigmented claw wall horn and underlying soft tissue showed pigment-containing cells in the coronary epidermis but not coronary dermis or in dermis or epidermis of laminae. Pigmentation appeared concentrated in melanosomes in cells along the basement membrane and was present uniformly throughout the epidermis and in cells lining horn tubules. There was no pigmentation detected in the soft tissue epidermis of claws selected visually for non-pigmented wall horn. The presence of melanosomes in epidermal cells from the pigmented coronary region was demonstrated by electron microscopy. The results suggest that pigmentation in the coronary region is associated with reduced initial development of hardness. The possible antagonism between antioxidant properties of melanins and requirement for an oxidative environment for disulphide bond formation in the cytoskeleton of horn cells is discussed.

The current study evaluated responses of early lactation Iranian Holstein cows to feeding roasted whole soybeans (SB) plus cottonseed meal (CSM), raw SB plus CSM and soybean meal (SBM) plus cottonseed (CS) in diets with lucerne hay and maize silage as the primary forage source. Treatments consisted of a total mixed ration that included 387 g forage/kg, supplemented with: (1) 120 g roasted SB/kg and 82 g CSM/kg, (2) 120 g raw SB/kg and 82 g CSM/kg, or (3) 120 g SBM/kg and 82 g CS/kg on a dry matter (DM) basis. Diets were offered to 14 multiparous Holstein cows (body weight=617·0 kg, days in milk=16·9) that were assigned randomly to one of three experimental diets for a 45-day trial. Dry matter intake (DMI) was significantly higher for the roasted SB plus CSM diet than for the raw SB plus CSM diet but the difference between the SB plus CSM diets and SBM plus CS was not significant. Yields of milk and 35 g fat-corrected milk (FCM)/kg and milk fat were significantly higher for the roasted SB plus CSM diet than for raw SB plus CSM and also for the SB plus CSM diets than for SBM plus CS. Milk protein concentration was significantly increased by about 2·0 g/kg by the SBM plus CS diet, but milk protein yield was the same for cows fed SBM plus CS, roasted SB plus CSM and raw SB plus CSM diets. Rumen ammonia N, plasma urea N (PUN) and milk urea N (MUN) concentrations were lower when the roasted SB plus CSM diet was fed. Ruminal pH and plasma glucose and β-hydroxybutyrate concentrations were not affected by dietary treatments. Plasma concentrations of essential amino acids (EAA), except Leu and Phe, were higher in cows fed the roasted SB plus CSM diet than in those fed raw SB plus CSM. The cows fed the SBM plus CS diet had the same concentrations of EAA, except Phe, as cows fed SB plus CSM diets. For diets based on lucerne hay and maize silage as the primary forage source, roasting of SB provides additional benefits over raw SB.