The comparative effect of spraying wheat straw, maize stover and maize cob with sodium hydroxide and alkaline (sodium hydroxide treated) hydrogen peroxide over a range of moisture contents was evaluated. The effect of concentration of hydrogen peroxide on straw subsequently ammoniated was also investigated. No differences (P < 0·05) were detected between sodium hydroxide and similar concentrations of sodium hydroxide used to provide alkali for alkaline hydrogen peroxide treatments. When however, gaseous ammonia was used as the source of alkali there were significant linear increases in degradability with increasing concentrations of hydrogen peroxide. At 48 h incubation, degradability values for untreated, ammonia-treated, 10, 50 and 100 g alkaline (ammonia) hydrogen peroxide per kg were 528, 595, 640, 676 and 716 for wheat straw, 618, 652, 683, 717 and 743 for maize stover and 392, 467, 585, 632 and 686 g/kg for maize cob respectively. It is concluded that the use of gaseous ammonia as the source of alkali seems a possible practical method of using hydrogen peroxide to increase degradability of straws.

A total of 96 gilts were used in two experiments to determine the effect of live weight and body composition at about 170 days of age on age of attainment of puberty, ovulation rate and subsequent reproductive efficiency.

In the first experiment 48 crossbred (Large White ♂ × Landrace ♀) gilts were randomly allocated at 21 days of age to each of six treatment groups which gave six different intakes of a protein-adequate diet. The food intakes were designed to achieve six live weights ranging from 59·6 to 118·0 kg at boar introduction at 170 days of age. Age at puberty declined linearly from 202 to 173 days with increasing live weight at boar introduction (P < 0·01). Ovulation rate at puberty was also positively affected by live weight at 170 days (P < 0·05).

In the second experiment, four littermates from each of 12 litters were randomly allocated at 28 days of age to four treatment groups. The groups were offered diets of varying protein adequacy at different feeding levels up to boar introduction at 165 days of age. The treatment groups comprised a factorial design with the factors being live weight (light, L or heavy, H) and fat level (lean, 1 or fat, f relative fat content). At boar introduction, mean live weights were 70·6, 71·5, 101·3 and 100·0 kg, and mean backfat depths were 11·3, 20·9, 21·7 and 27·0 mm for the LI, Lf, HI and Hf groups, respectively. Heavier gilts at boar introduction were younger (183 v. 199 days, P < 0·01) at puberty. Ovulation rate at puberty was also greater (11·0 v. 9·5, P < 0·05) in the heavier gilts. Gilts which were leaner at boar introduction also tended to attain puberty earlier (186 v. 195 days, P < 0·10) than fatter gilts.

In both experiments neither the subsequent reproductive efficiency of gilts after parturition nor the performance of their piglets was significantly affected by body weight or body composition at boar introduction.

An experiment was designed to determine whether an injection of 4 μg of the GnRH agonist buserelin (GnRH) followed, 5 days later, by an injection of 100 μg of prostaglandin F2α analogue (PGF), would give a level of oestrus synchronization and fertility comparable with a standard double dose PGF regime. A total of 200 Welsh Halfbred ewes were divided by live weight into two treatment groups using a system of random stratification during the 1994 breeding season. Ninety-one percent of the ewes treated with GnRH combined with PGF were mated by fertile rams within a 3-day period compared with 94% of ewes treated with two injections of PGF, 11-days apart. Returns to service for the two groups were 11·1% and 7·4%, respectively. There was no effect of treatment on lambing performance, as a similar percentage of ewes in the GnRH plus PGF group (88·8%) and the double dose PGF group (92·5%) lambed to synchronized oestrus. Gestation length, litter size and lamb birth weight were similar for both groups. These results demonstrate that GnRH combined with PGF will produce levels of oestrus synchronization and fertility comparable with a double dose PGF regime.

Cholesterol-loaded cyclodextrins (CLC) added to the sperm before cryopreservation enhance sperm quality after freeze-thawing in several cold shock-sensitive species, including cattle and goats. However, all studies conducted to date have used conventional protocols, in which sperm are cooled slowly to 5°C before freezing. As cholesterol plays a significant role in sperm cold shock resistance, it is possible that CLC-treated sperm can withstand cooling damage when the sperm are not cooled slowly to 5°C before freezing. In this study, we determined whether CLC-treated goat (1 mg CLC/120×106 sperm) and bull (2 mg CLC/120×106 sperm) sperm quality, after thawing, was different for sperm frozen using conventional protocols (including a slow cooling phase to 5ºC) and protocols in which the sperm were frozen from room temperature, without cooling the sperm slowly to 5°C before freezing. CLC-treated sperm exhibited higher percentages of plasma membrane-intact sperm than control sperm when cryopreserved using conventional protocols. In addition, CLC treatment enhanced both sperm motility and plasma membrane integrity when sperm were frozen directly from room temperature. However, this treatment did not fully prevent the damage of the sperm after cooling rapidly and subsequent freezing, as the sperm quality was lower than that presented by the samples frozen using the conventional protocol. The results are promising, but studies to optimize the protocols for freezing sperm directly from room temperature need to be conducted, as well as studies to determine how cryopreserving sperm in this manner affects other sperm functions.

Maturing patterns of carcass muscle, bone and fat were established using dissection data from 20 large mature size strain and 19 small mature size strain Merino rams. The rams were fed a pelleted ration soon after weaning and individual rams from both strains slaughtered at 6 kg increments in live weight from 18 kg to maturity at 116 and 91 kg for the large and small strains respectively.

Composition of mature rams of both strains was similar for the proportion of muscle and bone but there was a slightly greater proportion of fat in the larger strain.

The progress of each carcass tissue to maturity was assessed relative to progress of shorn full live weight to maturity. Maturing patterns of the three carcass tissues were not significantly different in the two strains. Muscle and bone were early maturing relative to live weight and fat late maturing.

The composition of the large and small mature size strains at the same live weight and at the same proportion of maturity was predicted from the maturity patterns of the carcass tissues and the composition of the mature rams. At the same live weight the large mature size strain had a greater proportion of bone and a smaller proportion of fat than the small mature size strain. At the same proportion of mature live weight, differences between the strains in proportional composition were reduced, and the large mature size strain had slightly more fat.

Some guidelines for comparison of strains of animals of different mature size are developed.

Heat stress is a global issue constraining pig productivity, and it is likely to intensify under future climate change. Technological advances in earth observation have made tools available that enable identification and mapping livestock species that are at risk of exposure to heat stress due to climate change. Here, we present a methodology to map the current and likely future heat stress risk in pigs using R software by combining the effects of temperature and relative humidity. We applied the method to growing-finishing pigs in Uganda. We mapped monthly heat stress risk and quantified the number of pigs exposed to heat stress using 18 global circulation models and projected impacts in the 2050s. Results show that more than 800 000 pigs in Uganda will be affected by heat stress in the future. The results can feed into evidence-based policy, planning and targeted resource allocation in the livestock sector.

The particle size of the forage has been proposed as a key factor to ensure a healthy rumen function and maintain dairy cow performance, but little work has been conducted on ryegrass silage (GS). To determine the effect of chop length of GS and GS:maize silage (MS) ratio on the performance, reticular pH, metabolism and eating behaviour of dairy cows, 16 multiparous Holstein-Friesian cows were used in a 4×4 Latin square design with four periods each of 28-days duration. Ryegrass was harvested and ensiled at two mean chop lengths (short and long) and included at two ratios of GS:MS (100:0 or 40:60 dry matter (DM) basis). The forages were fed in mixed rations to produce four isonitrogenous and isoenergetic diets: long chop GS, short chop GS, long chop GS and MS and short chop GS and MS. The DM intake (DMI) was 3.2 kg/day higher (P<0.001) when cows were fed the MS than the GS-based diets. The short chop length GS also resulted in a 0.9 kg/day DM higher (P<0.05) DMI compared with the long chop length. When fed the GS:MS-based diets, cows produced 2.4 kg/day more (P<0.001) milk than when fed diets containing GS only. There was an interaction (P<0.05) between chop length and forage ratio for milk yield, with a short chop length GS increasing yield in cows fed GS but not MS-based diets. An interaction for DM and organic matter digestibility was also observed (P<0.05), where a short chop length GS increased digestibility in cows when fed the GS-based diets but had little effect when fed the MS-based diet. When fed the MS-based diets, cows spent longer at reticular pH levels below pH 6.2 and pH 6.5 (P<0.01), but chop length had little effect. Cows when fed the MS-based diets had a higher (P<0.05) milk fat concentration of C18 : 2n-6 and total polyunsaturated fatty acids compared with when fed the GS only diets. In conclusion, GS chop length had little effect on reticular pH, but a longer chop length reduced DMI and milk yield but had little effect on milk fat yield. Including MS reduced reticular pH, but increased DMI and milk performance irrespective of the GS chop length.

Pre-slaughter transportation may affect poultry welfare and mortality rates. A retrospective analysis was conducted to examine the effect of environmental, management and individual factors on the percentage of dead birds during pre-slaughter transportation (dead-on-arrival, DOA). The variables accounted for in the analyses included: environmental temperature, travel duration, genetic line, gender, crate type and crate stocking density. Among the 41 452 loads of turkeys (34 696 388 birds) and 3241 of end of lay hens (21 788 124 birds) transported to three large abattoirs in northern Italy in a 3-year period, the median DOA was 0.14% in turkeys, and 0.38% in hens. In turkeys, travel duration longer than 30 min, temperature higher than 26°C and high in-crate densities were associated with increased DOA. In winter (⩽2°C), high stocking densities did not reduce the mortality risk from cold stress; on the contrary, for stocking densities either near to or just above the maximum density in EC Reg. 1/2005, the DOA risk was greater than for loads with densities of 10 kg/m2 less than the EC maximum. Male birds and specific genetic lines also showed a higher DOA. In hens, transportation lasting longer than 2 h and the brown-feathered breed were associated with higher DOA. Dead-on-arrival progressively increased with travel duration, remaining constant between 4 and 6 h and peaking at 8 h (median: 0.57%). The maximum DOA increase was detected during winter. These results show that several species-specific factors may lead to increased risk of mortality.

Footbaths represent a potentially useful strategy for the prevention of claw infectious diseases by treating a large number of animals concomitantly. Nevertheless, under field conditions, footbath solutions are exposed to increasing number of animal passages and therefore, to different volume losses and concentrations of manure contamination which could alter their presumed bactericidal activity. Across increasing number of cow passages, the organic matter (OM) concentration, the microbial load (ML) and the residual volumes were assessed in six commercial farms. The results indicate that the OM concentration and ML increased linearly with the number of passages of animals, and with the number of defecations in the footbath. The OM concentrations and the ML were not impacted by the farm’s feet hygiene status (clean, fair and dirty), suggesting that probably the increasing number of cow passages and defecations influenced more the contamination of footbaths than the hygiene of the feet. In all the farms the volumes decreased drastically after 200 cow passages (50%). The OM concentrations after 150 and 200 cow passages did not exceed the regulatory concentrations in which disinfectant products should demonstrate to still be effective (20 g/l), and coincide with the often advised renewal rates. The findings of this study suggested that beyond the footbath contamination by OM, the renewal rates must be mainly adapted according to the remaining volume to guarantee that the entire foot is covered and therefore assure the topical action of the solution. This study highlights the importance of footbath designs for the successful implementation of these strategies in practice.

Current feeder space recommendations in laying hen welfare guidelines are inconsistent among and within countries. One determining criterion forming the recommendations (e.g. 12.0 cm/hen for the EU guideline) is that all birds can feed simultaneously. However, if there are other resources in the environment, as in enriched colony housing (ECH), it is unknown whether group-housed hens will choose to feed simultaneously. This study assesses the impact of feeder space on feeding behavior of 60 laying hens (W-36) in ECH using a ultra-high frequency radio-frequency identification-based tracking system. The feeder spaces investigated were 12.0, 9.5, 8.5 and 6.5 cm/hen, achieved by blocking portions of the overall feeder access to keep hens at the same stocking density. Each feeder space treatment, randomly assigned over the course of the experiment, lasted for 7 consecutive days. Feeding behaviors were characterized as daily time spent at the feeder (TS, min/hen-day), daily frequency of visits to the feeder (FV, #/hen-day), and maximum or average percentage of hens feeding simultaneously (MPB, APB, %). Group-average daily feed intake (FI, g/hen-day), water use (WU, g/hen-day), and hen-day egg production (HDEP, %) were also measured. The results revealed that at 12.0 cm/hen, where unoccupied feeder space was present, a maximum of 59.0±1.4% (average of 31.7±0.3%) hens fed simultaneously. No significant differences were detected among 12.0, 9.5 and 8.5 cm/hen in TS (293±10, 286±10 and 281±10 min/hen-day) and MPB (59.0±1.4, 57.3±1.4 and 53.3±1.4%) (P>0.05). The outcome of no significant differences also held true between 12.0 and 9.5 cm/hen in APB (31.7±0.3 v. 30.8±0.3%) and between 9.5 and 8.5 cm/hen in all response variables measured (P>0.05). However, there were significant differences in APB between 6.5 cm/hen and all other treatments; in TS and FV between 6.5 and 9.5 cm/hen; and in MPB between 6.5 and 12 cm/hen (P<0.05). Considerable inter-hen variability was observed in TS (CV varying from 28.0% to 32.1%) and FV (CV varying from 26.5% to 27.8%). All the feeder spaces tested showed no significant impact on FI, WU or HDEP (P>0.05). The results revealed that synchronous feeding of hens in the ECH did not increase with increasing feeder space. However, it is worth noting that lower feeder space may lead to aggression or frustration which was not quantified in the current study.

Determining welfare status in a population is the first step in efforts to improve welfare. The primary objective of this study was to explore a new epidemiological approach for analysis of data from official competent authorities that pertain to compliance with animal welfare legislation. We reviewed data already routinely collected as part of Swedish official animal welfare inspections for 2010–13, using a checklist containing 45 checkpoints (CPs). These covered animal-, resource- and management-based measures of equine welfare. The animal-based CPs were measures that directly related to the animal and included social contact, body condition, hoof condition and cleanliness. Non-compliance with one or more of the animal-based CPs was used as a binary outcome of poor equine welfare; 95% confidence intervals (CI) were estimated using the exact binomial distribution. Associations were determined using multivariable logistic regression, adjusting for clustering on premises. Resource- and management-based CPs (model inputs) were reduced by principal component analysis. Other input factors included premises characteristics (e.g. size, location) and inspection characteristics (e.g. type of inspection). There were 30 053 premises with horses from 21 counties registered by the Swedish Board of Agriculture. In total 13 321 inspections of premises were conducted at 28.4% (n=8532) of all registered premises. For random inspections, the premises-prevalence of poor equine welfare was 9.5% (95% CI 7.5, 11.9). Factors associated with poor equine welfare were non-compliance with requirements for supervision, care or feeding of horses, facility design, personnel, stable hygiene, pasture and exercise area maintenance, as well as the owner not being notified of the inspection, a previous complaint or deficiency, spring compared with autumn, and not operating as a professional equine business. Horses at premises compliant with stabling and shelter requirements had significantly better welfare if they also complied with documentation requirements. We present a novel approach for analysis of equine welfare data from regulatory inspections by the official competent authorities, and propose on-going analyses and benchmarking of trends in animal-based measures over time. We also suggest how such a database could be further improved to facilitate future epidemiological analyses of risk factors associated with poor equine welfare. The study has implications for other competent authorities and researchers collaborating in the area of animal welfare epidemiology.

1. The voluntary dry-matter intake, water intake and rate of live-weight gain of indigenous, exotic and crossbred cattle on low- and medium-roughage diets have been compared under similar conditions of management.

2. At similar live weights and on similar diets exotic cattle usually have a higher food intake than indigenous animals.

3. When roughage was freely available the voluntary dry-matter intake of both types of cattle increased.

4. Water intake was closely related to dry-matter intake and varied with the nature of the diet. The ratio of water to dry-matter intake was not affected by live weight and varied only slightly between the different types of cattle.

5. Exotic cattle were generally more efficient than indigenous cattle of comparable live weight in converting food into live-weight gain; crossbred animals were intermediate. It is suggested that this largely reflects their higher intake of food relative to their maintenance requirement.

6. One group of indigenous animals that were initially mature but under weight gained weight as quickly, and converted their food as efficiently, as did exotic animals.

Europe’s roadmap to a low-carbon economy aims to cut greenhouse gas (GHG) emissions 80% below 1990 levels by 2050. Beef production is an important source of GHG emissions and is expected to increase as the world population grows. LIFE BEEF CARBON is a voluntary European initiative that aims to reduce GHG emissions per unit of beef (carbon footprint) by 15% over a 10-year period on 2172 farms in four large beef-producing countries. Changes in farms beef carbon footprint are normally estimated via simulation modelling, but the methods current models apply differ. Thus, our initial goal was to develop a common modelling framework to estimate beef farms carbon footprint. The framework was developed for a diverse set of Western Europe farms located in Ireland, Spain, Italy and France. Whole farm and life cycle assessment (LCA) models were selected to quantify emissions for the different production contexts and harmonized. Carbon Audit was chosen for Ireland, Bovid-CO2 for Spain and CAP’2ER for France and Italy. All models were tested using 20 case study farms, that is, 5 per country and quantified GHG emissions associated with on-farm live weight gain. The comparison showed the ranking of beef systems gross carbon footprint was consistent across the three models. Suckler to weaning or store systems generally had the highest carbon footprint followed by suckler to beef systems and fattening beef systems. When applied to the same farm, Carbon Audit’s footprint estimates were slightly lower than CAP’2ER, but marginally higher than Bovid-CO2. These differences occurred because the models were adapted to a specific region’s production circumstances, which meant their emission factors for key sources; that is, methane from enteric fermentation and GHG emissions from concentrates were less accurate when used outside their target region. Thus, for the common modelling framework, region-specific LCA models were chosen to estimate beef carbon footprints instead of a single generic model. Additionally, the Carbon Audit and Bovid-CO2 models were updated to include carbon removal by soil and other environmental metrics included in CAP’2ER, for example, acidification. This allows all models to assess the effect carbon mitigation strategies have on other potential pollutants. Several options were identified to reduce beef farms carbon footprint, for example, improving genetic merit. These options were assessed for beef systems, and a mitigation plan was created by each nation. The cumulative mitigation effect of the LIFE BEEF CARBON plan was estimated to exceed the projects reduction target (−15%).

In this study, the level of technical efficiency of 58 sheep farms rearing the Chios breed in Greece was measured through the application of the stochastic frontier analysis method. A Translog stochastic frontier production function was estimated using farm accounting data of Chios sheep farms and the impact of various socio-demographic and biophysical factors on the estimated efficiency of the farms was evaluated. The farms were classified into efficiency groups on the basis of the estimated level of efficiency and a technical and economic descriptive analysis was applied in order to illustrate an indicative picture of their structure and productivity. The results of the stochastic frontier model indicate that there are substantial production inefficiencies among the Chios sheep farms and that these farms could increase their production through the improvement of technical efficiency, whereas the results of the inefficiency effects model reveal that the farm-specific explanatory factors can partly explain the observed efficiency differentials. The measurement of technical inefficiency and the detection of its determinants can be used to form the basis of policy recommendations that could contribute to the development of the sector.

1. Calorimetric evaluation of the nutritive value of feeds for ruminants has, of necessity, involved using mature sheep isolated in respiration chambers. This experiment was designed to examine how such information relates to growing lambs reared in different ways.

2. Lambs were either completely isolated, individually fed, or fed in groups. Two lambs in each group were fed to gain 100 g/day (medium) and two to gain 200 g/day (high). Calorimetric measurements were made on individuals or groups at intervals over 20 weeks.

3. All lambs fed to gain 100 g/day consumed their entire ration, isolated lambs gained on average 123 g/day and the others 160 g/day. On the ‘high’ ration isolated lambs ate less than the others and gained 178 as against 228 g/day.

4. Metabolizable energy intake, heat production and thus energy retention were similar in all groups offered the ‘medium’ ration. Differences in energy retention on the ‘high’ ration were related to differences in intake.

5. The net availability for weight gain of the diet (kf) estimated from energy balance trials conducted throughout the growth period (0·61) agreed well with that predicted from its content of metabolizable energy (0·63).

6. Estimates of the caloric density of the weight gain suggested that on the ‘medium’ ration the isolated lambs retained substantially more energy as fat than those reared in groups. These observations are discussed in relation to the design and interpretation of calorimetric experiments to predict the nutritive value of feeds for growing lambs.

Due to their functional similarity to estradiol, phytoestrogens could prove to be beneficial in late gestating sows. The goal of this study was to determine the impact of providing the phytoestrogen genistein during late pregnancy on the performance of sows and their litters. In total, 56 gilts were equally divided into the two following groups on day 90 of gestation: (1) controls (CTL); and (2) two daily i.m. injections of 220 mg of genistein (GEN). Treatments were carried out until farrowing. Jugular blood samples were collected from 16 gilts/treatment on days 89 and 110 of gestation, and on days 3 and 21 of lactation. Milk samples were also obtained from those sows on day 3 of lactation. A male piglet from 16 CTL and 15 GEN litters was slaughtered at 24 h postpartum and a blood sample was obtained. The liver, heart and visceral organs were weighed and the semitendinosus (ST) muscle was collected and carcass composition was determined. The treatment increased (P<0.05) the concentrations of genistein and daidzein in the plasma of gilts on day 110 of gestation and of genistein in the plasma of piglets at 24 h postpartum. It also increased IGF1 concentrations in gilts at the end of the treatment period (P<0.05). Genistein had no impact (P>0.1) on weight or backfat loss of sows during lactation, milk composition or weights of piglets. The pre-weaning mortality rate of piglets was very low (<7%), yet the odds ratio comparing CTL with GEN sows indicated almost twice as many chances of pre-weaning deaths occurring in litters from CTL than GEN sows. Weights of the piglet carcasses were similar for both treatments, as well as weights of the various organs and of the ST muscle (P>0.1). However, carcasses from GEN litters contained more fat than those from CTL litters (9.63% v. 8.34%, P<0.05). None of the biochemical properties of the ST muscle differed between groups (P>0.1). In conclusion, injecting gilts with 440 mg/day of genistein in late gestation increased IGF1 concentrations in gilts and carcass fat in neonatal piglets, but had minimal effect on muscle development of piglets at birth and on the performance of lactating sows and their litters.

Forty pregnant F1 crossbred dairy cows (20 Friesian × Boran and 20 Simmental × Boran) were stratified in a 2 × 2 diet × work factorial arrangement (not working-not supplemented, NWNS; not working-supplemented, NWS; working-not supplemented, WNS; and working-supplemented, WS) were used to study the effect of work and diet supplementation on roughage intake, apparent digestibility of nutrients, digesta kinetics and plasma metabolites. Dry matter (DM) and organic matter (OM) intakes were greater for working than for non-working cows. Work and supplementation increased DM and OM in vivo apparent digestibility. This effect was particularly significant when comparing working cows at rest and at work. Passage rate and rumen mean retention of Cr-mordanted hay were similar for working and for nonworking cows. Liquid turn-over rate of Co-ethylene diamine tetra acetic acid (EDTA) was lower and rumen mean retention time of Co-EDTA was greater in working than in non-working cows whether supplemented or not. Working coios had lower plasma glucose during and immediately after working than non-working cows. Plasma non-esterified fatty acid (NEFA) was higher in working cows at the end of the working period and after rest between working hours. This effect was greater in non-supplemented than in supplemented cows. In working cows, β-hydroxybutyrate was lower at the end of working hours than in non-working cows. Lactate was greater in working than in non-working cows after the 3rd and 4th hours of work. Digesta kinetics could explain only partially the possible mechanisms responsible for greater roughage intake and apparent digestibility in working cows. The decrease of plasma glucose and the increase in NEFA during work indicates an increasing utilization of NEFA by muscle during consecutive working hours.

An analysis was conducted on milk production data collected from 1954 to 1981 at Turrialba, Costa Rica. The local conditions are humid and tropical without a sharply defined dry season. The data included purebred Central American Milking Criollos, Jerseys, their reciprocal F, crosses and backcrosses. Two data sets were created: one with minimum restrictions intended to include production data from all calvings, and another data set intended to include only lactations with normal let-down without the presence of the calf. Data were analysed by maximum likelihood according to a model that included the fixed effects of year of calving, parity of lactation, breed or cross and the regression on year of birth of the sire's first daughter and random effects of sire, cow and error. Breed or cross differences were significant for milk yield, fat-corrected milk (FCM) yield and lactation length but were not significant for fat concentration.

F1 crosses were superior to both parental breeds for milk and FCM yields for both data sets; there were no significant reciprocal effects. The ¾ Criollo backcross had significantly lower milk and FCM yields and shorter lactations than did the F1 or ¾ Jersey. These results suggest that breeding programmes for this type of environment should backcross F1's to Jersey sires and use criss-crossing from then on. The proportion of heterosis for milk, FCM, butterfat concentration and lactation length was 0·26, 0·28 0·02 and 0·15 for minimum-restriction lactations and 0·21, 0·22, 0·01 and 0·09 for normal lactations. Heritabilities for milk, FCM, fat concentration and length of lactation were 0·44, 0·42, 0·28 and 0·41 for minimum restriction lactations and 0·28, 0·27, 0·35 and 0·08 for normal lactations. The relatively higher values for minimum-restriction records suggest a strong genetic effect on ease or difficulty of milk let-down.

A significant number of lambs born each year in Australia die within 72 h of birth. Periods of high wind, combined with rain and low temperatures can lead to marked increases in the mortality level. Under these climatic conditions mortality levels may be reduced with the provision of shelter. This study used contact loggers to compare interactions between ewes with twin lambs across two shelter types (Hessian and shrubs), while also comparing ewes with single and twin lambs in a single shelter type (Hessian). The contact loggers record the time of the initial contact (within approximately 4 to 5 m) between collared animals and the duration of each contact. Contact levels between ewes immediately after lambing were only 10% of the initial levels (1 h/day). For single-born lambs, lambs averaged 11 h contact per day with their mother, while for twinborn lambs, each lamb averaged 9.25 h/day with its mother and 14.7 h/day with its sibling. The level of contact between ewes and each of their offspring in the Hessian was 24% lower (P < 0.05) for ewes with twin lambs than with singles. For ewes with twin lambs the level of contact was 17% lower (P < 0.05) in the Hessian shelter compared with shrub shelter. We conclude that shelter type and birth number can affect the level of contact between ewes and their offspring.

An experiment was carried out to examine the performance of young steers given basal diets of either silage or ammoniated hay ad libitum, with or without a daily supplement of fish meal, equivalent to 0·75 g/kg live weight, over 16 weeks. Serial slaughter of animals was carried out to examine changes in body composition during the winter feeding period and the subsequent grazing season.

There was no difference in the intakes of hay and silage organic matter over the 16 weeks of treatment. Despite the increased intake of nitrogen on the ammoniated-hay diet there was no increase in the rate of protein gain. By turn-out the steers given silage had higher empty body and carcass weights, and greater contents of fat and energy. The increased rates of empty body-weight, carcass, protein, water and energy gains achieved when the supplement was given were similar for both basal diets. There was no effect of winter feeding treatment on changes in body composition during the grazing period, so that at the end of the summer period the silage-fed animals still had heavier empty body and carcass weights. Attention is also drawn to the possible dangers of feeding hay treated with anhydrous ammonia at high temperatures to such cattle.