The study reported in this paper was conducted to evaluate the digestibility of dietary carbohydrates (‘starch and sugars’ (S), neutral-detergent fibre (NDF), acid-detergent fibre (ADF)) and organic matter (OM) in the different parts of the equine digestive tract (stomach, jejuno-ileum, caecum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, small colon and faeces). Three horses were given a standard diet (D1) based on fibrous pellets and straw and four were offered a high energy diet (D2) based on starch pellets and meadow hay. The digesta collection procedure, by total tract removal, permitted measurement of organ length, and dry matter and volume of digesta. Acid-detergent lignin (ADL) and acid insoluble ash (AIA) were used as natural digestibility markers. It was shown that AIA and ADL gave coherent data for ‘starch and sugars’ digestibility evaluation. ADL was a more relevant marker for parietal carbohydrates and OM digestibilities in horses given D1, whereas AIA have been preferred to evaluate these components digestibilities in horses offered D2. In horses given D1, precaecal OM digestibility coefficient varied from -0·04 to 0·20 whereas it varied from 0·46 to 0·62 in horses receiving D2. For both pellets, the results showed a considerable S digestibility occurring in the stomach (0·69 and 0·60 for D1 and D2 respectively) and this continued in the small intestine (0·88 and 0·89 for D1 and D2 respectively). With the exception of D2, structural carbohydrate fractions of the foods were poorly digested in the pre-caecal digestive parts. In the hindgut, OM digestibility coefficient varied from 0·47 to 0·60 for D1 and from 0·33 to 0·51 for D2. In horses given D1, highest digestibility was observed for each dietary carbohydrate in the left dorsal colon where it reached 0·99 for S; 0·45 for NDF and 0·40 for ADF. In horses receiving D2, the dietary components’ digestibilities increased regularly along the hindgut up to the faeces. The D2 structural fractions (NDF and ADF) digestibilities in the hindgut and faeces were lower than in horses given D1. These results not only confirmed that high energy diets like D2 can affect structural carbohydrate digestion in the horse hindgut but also indicated that a large amount of the energy part of the pelleted morning meal is broken down in the stomach.

In temperate latitudes sheep have a seasonal reproductive behaviour, which imposes strong constraints on husbandry in terms of work organization and availability of animal products. During the last 50 years, researchers have focused on understanding the mechanisms driving small ruminants’ reproduction cycles and finding ways to control them. This characteristic is inherited from their wild ancestor. However, the history of its evolution over the 10 millennia that separates present day European sheep from their Near Eastern ancestors’ remains to be written. This perspective echoes archaeologists’ current attempts at reconstructing ancient pastoral societies’ socio-economical organization. Information related to birth seasonality may be retrieved directly from archaeological sheep teeth. The methodology consists of reconstructing the seasonal cycle record in sheep molars, through sequential analysis of the stable oxygen isotope composition (δ18O) of enamel. Because the timing of tooth development is fixed within a species, inter-individual variability in this parameter reflects birth seasonality. A review of the data obtained from 10 European archaeological sites dated from the 6th to the 3rd millennia BC is provided. The results demonstrate a restricted breeding season for sheep: births occurred over a period of 3 to 4 months, from late winter to early summer at latitudes 43°N to 48°N, while a later onset was observed at a higher latitude (59°N). All conclusions concurred with currently held expectations based on present day sheep physiology, which, aside from the historical significance, contributes to the reinforcing of the methodological basis of the approach. Further study in this area will permit regional variability attributable to technical choices, within global schemes, to be fully reported.

A total of 28 adult V-line rabbits were fed ad libitum a control diet or a diet supplemented with 0.5%, 1.0% and 1.5% soybean lecithin (SL) for 12 weeks. Bucks that received 0.5%, 1.0% or 1.5% dietary SL had a higher ejaculate volume, mass motility, sperm concentration, total sperm output and total motile sperm. Dietary SL reduced the percentage of dead sperm and increased the normal sperm, and this concurred with an increase in blood testosterone concentration. Blood and seminal plasma total lipid, acid phosphatase and seminal plasma alkaline phosphatase were significantly increased because of inclusion of SL. Interestingly, SL reduced blood and seminal plasma thiobarbituric acid-reactive substances while increasing blood and seminal plasma glutathione content, glutathione S-transferase, glutathione peroxidase and superoxide dismutase activity. Conception rate and litter size at birth and weaning were also significantly improved. Practically, it could be suggested that SL is a suitable supplement for improving semen quality, antioxidant status, reproductive traits and the economic efficiency of V-line rabbit bucks and 1% is an adequate concentration.

It has been suggested that United Kingdom recommendations for feeding the neonatal calf (∼500 g milk replacer (MR)/day; ∼200–230 g CP/kg milk powder) are inadequate to sustain optimal growth rates in early life. The current study was undertaken with 153 high genetic merit, male and female Holstein-Friesian calves (PIN2000 = £48) born between September and March, with heifers reared and bred to calve at 24 months of age. Calves were allocated to one of four pre-weaning dietary treatments arranged in a 2 MR feeding level (5 v. 10 l/day) × 2 MR protein content (210 v. 270 g CP/kg dry matter (DM)) factorial design. MR was reconstituted at a rate of 120 g/l of water, throughout, and was offered via computerised automated milk feeders. Calves were introduced to pre-weaning diets at 5 days of age and weaned at day 56. During the first 56 days of life, calves offered 10 l MR/day had significantly higher liveweight gains (P < 0.001) than calves fed 5 l MR/day. No significant differences in liveweight gain were found between calves fed 210 g CP/kg DM MR and those fed 270 g CP/kg DM MR from birth to day 56. Differences in live weight and body size due to feeding level disappeared by day 90. Neither MR feeding level nor MR CP content affected age at first service or age at successful service, and with no milk production effects, the results indicate no post-weaning benefits of increased nutrition during the milk-feeding period in dairy heifers.

Thirty-six Large White × (Large White × Landrace) young female pigs (gilts) were allocated to one of nine treatments. These were 30 min daily boar contact from 125, 132, 139, 146, 153, 160, 167, 174 or 181 days of age. Gilts were fed so as to maintain them on a pre-determined growth curve, gaining 0·45 kg per day. Once puberty had been detected, gilts were mated at the next (second) oestrous period and subsequently slaughtered 20 days post coitum.

The interval from first boar contact to puberty was significantly longer (P<0·05) amongst gilts first exposed to a boar at ages below 139 days. Amongst gilts older than this the interval was similar. Though the 174- and 181-day groups were significantly older at puberty (P<0·05) no significant differences were observed amongst the younger age groups. Synchronization of pubertal oestrus appeared to be better for the 160- and 167-day groups, with three out of four gilts reaching puberty within an 8-day period. There was no indication that weight at puberty, ovulation rate, percentage embryo survivval, or number of viable embryos at 20 days post coitum were affected by treatment.

From the results it appears that the optimal gilt age at which to commence boar contact, in terms of age at puberty, interval from first boar contact to puberty and synchronization of the pubertal oestrus, is in the age range 160 to 170 days.

Monthly herd recording data from Friesian cows in south-east Queensland are used to evaluate 20 models of the lactation curve, 10 being drawn from the literature and 10 being original. The curve of Wood (1967) with equation y =a nb exp(–cn),and its modificationy =a nfc/cosh(en), generally gave the lowest values for the error mean square across all seasons of calving. However, the model which predicts a constant initial yield, followed by a linear decline,y =a forn =Sc, y =a - b(n –c) forn > c, is as good as the previous two models for winter calving cows. Hence it is a useful representation of the lactation curve in south-eastern Queensland, where about 40% of cows are calved in winter. The inverse polynomial modely =nl(a +bn + en2) is a useful model for lactations commencing in the summer months.

The effects of body condition score (BCS) of 2·0 or 3·0 units at calving (low v. moderate), post-partum energy intake at 0·6 or 1·0 MJ metabolizable energy (ME) per day per kg M0·75 (low v. high) and unrestricted or restricted (once daily) suckling on the ability of cows to ovulate were studied in a 2 ✕ 2 ✕ 2 factorial design with each treatment replicated eight times. Calf isolation and restricted suckling were imposed shortly after selection of the first dominant follicle (DF) to emerge after day 21 post partum. The episodic release of LH (sampled at 15-min intervals for 10 h) was determined 48 h before and 48 h after the day calf isolation and restricted suckling commenced. Additional blood samples were collected weekly for plasma insulin determination. The mean interval from calving to first ovulation was shorter for cows in moderate than low BCS at calving (47·8 v. 57·1 days, s.e.d. = 4·50, P < 0·05), and for cows suckling once daily than for those with unrestricted suckling (42·9 v. 62·0 days, s.e.d. = 4·50, P < 0·001). Post-partum nutrition did not affect this interval. Mean LH pulse frequency prior to the start of restricted suckling was higher for cows of moderate than low BCS at calving (3·2 v. 1·6 pulses per 10 h, s.e.d. = 0·60, P < 0·05). Subsequently, LH pulse frequency was higher for cows suckling once daily than for those with unrestricted suckling (4·0 v. 2·2 pulses per 10 h, s.e.d. = 0·82, P < 0·05). More cows in moderate than low BCS ovulated the first DF to emerge after day 21 post partum (within 4 to 6 days) in response to restricted suckling (69 v. 25%, P < 0·05). LH pulse frequency prior to restricted suckling increased (P < 0·05) with plasma insulin concentration (categorized as low, < 5; moderate, 5 to 8; and high, >8 mIU per l). There were indications of interactions between suckling treatment and BCS (P < 0·08), and suckling treatment and plasma insulin concentration (P < 0·06), on LH pulse frequency, which suggested that calf restriction could alleviate the suppressive effects of under nutrition on episodic LH release. Amongst cows suckling once daily, the non-ovulating animals had fewer LH pulses prior to restricted suckling and smaller, slower growing DF, indicating an inability of the DF to respond to increased LH pulse frequency following calf restriction. Cows of moderate BCS, particularly those with moderate to high levels of plasma insulin (³ 5 mIU per l), responded favourably to restricted suckling. In contrast, excessively thin cows with low plasma insulin concentrations (<5 mIU per l), that had most to gain from restricted suckling, responded poorly.

To analyse trends in greenhouse gas (GHG) emissions from production and consumption of animal products in Sweden, life cycle emissions were calculated for the average production of pork, chicken meat, beef, dairy and eggs in 1990 and 2005. The calculated average emissions were used together with food consumption statistics and literature data on imported products to estimate trends in per capita emissions from animal food consumption. Total life cycle emissions from the Swedish livestock production were around 8.5 Mt carbon dioxide equivalents (CO2e) in 1990 and emissions decreased to 7.3 Mt CO2e in 2005 (14% reduction). Around two-thirds of the emission cut was explained by more efficient production (less GHG emission per product unit) and one-third was due to a reduced animal production. The average GHG emissions per product unit until the farm-gate were reduced by 20% for dairy, 15% for pork and 23% for chicken meat, unchanged for eggs and increased by 10% for beef. A larger share of the average beef was produced from suckler cows in cow–calf systems in 2005 due to the decreasing dairy cow herd, which explains the increased emissions for the average beef in 2005. The overall emission cuts from the livestock sector were a result of several measures taken in farm production, for example increased milk yield per cow, lowered use of synthetic nitrogen fertilisers in grasslands, reduced losses of ammonia from manure and a switch to biofuels for heating in chicken houses. In contrast to production, total GHG emissions from the Swedish consumption of animal products increased by around 22% between 1990 and 2005. This was explained by strong growth in meat consumption based mainly on imports, where growth in beef consumption especially was responsible for most emission increase over the 15-year period. Swedish GHG emissions caused by consumption of animal products reached around 1.1 t CO2e per capita in 2005. The emission cuts necessary for meeting a global temperature-increase target of 2° might imply a severe constraint on the long-term global consumption of animal food. Due to the relatively limited potential for reducing food-related emissions by higher productivity and technological means, structural changes in food consumption towards less emission-intensive food might be required for meeting the 2° target.

Reproductive performance is receiving increased attention from beef cattle producers. There are concerns that intensive selection for carcass traits might reduce the reproductive performance of females. Genetic parameters among six carcass traits and, age at first calving (AFC), gestation length (GL), days open (DO) and calving interval (CI) under year-round artificial insemination were estimated. Reproductive traits were extracted from 174005 calving records of Japanese Black cows and were analysed with 31364 carcass records. The restricted maximum likelihood procedure under animal models was used to estimate the parameters. Heritabilities of AFC, GL, DO and CI were estimated to be 0.20, 0.40, 0.05 and 0.05, respectively, and those of carcass traits were higher, ranging from 0.38 to 0.56. Genetic correlations of CI with AFC and GL were 0.25 and 0.16, respectively, while no relationship was observed between AFC and GL. Correlations among carcass traits were generally favourable and a slightly negative estimate was obtained between subcutaneous fat thickness and marbling score. Genetic correlations for AFC were -0.27 with carcass weight and -0.24 with marbling score. In contrast, GL, DO and CI were genetically independent of carcass traits. Genetic relationships between reproductive and carcass traits were generally low, and therefore serious antagonism was not observed. The results suggested that selection for carcass traits would not compromise genetic progress in reproductive traits.

The experiment was undertaken to quantify the α and γ-tocopherols accumulation in muscle and backfat from Iberian pigs given food free-range as affected by the time of free-range feeding or the weight gained during the fattening in free-range. Pigs were given their food in a free-range production system with pasture and acorns (Quercus rotundifolia) for different periods of time: 46 days (free-range 3), 83 days (free-range 2) and 111 days (free-range 1). A control was given food free-range for 0 days. In addition another experiment was developed to determinate the effect of the the weight gained on the tocopherols accumulation at a similar period of time (111 days) given food free-range: one group gained 68·7 kg of weight (free-range A) and the other 43·6 kg (free-range B). The concentration of γ-tocopherol significantly (P<0·0001) increased after 83 days of feeding in the longissimus dorsi (LD) and biceps femoris (BF) muscles, and after 111 days in the inner and outer backfat layers. The concentration of α-tocopherol was not statistically affected by the days of free-range feeding in any case. Iberian pigs that put on more weight had significantly (P< 0·0001) higher concentration of α and γ-tocopherols in the inner and outer backfat layers, and α-tocopherol in the BF muscle than those given food free-range B. However, no differences were detected in the proportion of α-tocopherol in the LD and γ-tocopherol in the LD and BF. The γ-tocopherol content of LD and BF muscles depending on the days of feeding were adjusted to linear and quadratic regressions (R2=0·8705 and 0·8697, respectively), while the outer and inner backfat layers were linear equations (R2=0·8480 and 0·8119, respectively). However, the γ-tocopherol concentration as affected by the weight gained in free-range showed in all tissues a linear and a quadratic trend that were adjusted to exponential responses. The α-tocopherol content was affected by the γ-tocopherol concentration in muscle and outer backfat layer. The tocopherol concentration (α and γ-tocopherols) in the backfat layers may discriminate better between the pigs of high quality that were given food free-range for a long period of time and those that stayed an intermediate period. However, to discriminate between the pigs on formulated food and those given food free-range, the quantification of the γ-tocopherol concentration in muscle could be a better indicator.

The susceptibility of whole and rolled cereal and legume seeds to microbial attack within the rumen of cows was examined by incubating seeds in nylon bags in the rumen for 24,48 and 72 hr. With whole, intact seeds the husked cereal grains were less susceptible than naked grains and legume seeds. Inter-varietal differences were observed with maize, oats and barley. Breaking the cereal grains before incubation considerably increased the losses of dry matter. Digestibility trials with non-lactating cows confirmed that barley, sorghum, wheat and oats were poorly digested when given whole, and considerable variation was recorded between individual cows in their ability to digest whole grains. Rolling the grains before feeding made the greatest improvement in digestibility with sorghum, wheat and barley and the least with oats.

Dietary changes alter dairy cow milk fat concentration (MFC) and yield (MFY) through modifications in the supply of nutrients, which act as precursors or inhibitors of mammary fat synthesis. The current models used to formulate dairy cow diets cannot predict changes in milk fat. The knowledge of the effects of the nutrients on milk fat would help to progress toward this prediction. To this end, we quantified and compared the milk fat responses to variations in the supply of seven nutrients derived from digestion: volatile fatty acids, glucose, proteins, long-chain fatty acids (LCFA) and t10,c12-conjugated linoleic acid (CLA). A database was compiled from studies involving digestive infusions of these nutrients in dairy cows. It included 147 comparisons between a nutrient infusion and a control treatment. The nutrient infusions were limited to the range of physiological variations to mimic nutrient changes after dietary modifications. We established models for the response of MFC, MFY and milk fatty acid (FA) composition to the supply of each nutrient. MFC and MFY responses to the nutrients were significant and linear, except for the MFC response to glucose that was curvilinear. The nutrients differed in their effects on MFC and MFY: acetate, butyrate and LCFA increased MFC and MFY, whereas propionate, glucose and t10,c12-CLA decreased them. Protein infusions increased MFY and decreased MFC because of an increase in milk yield. The effects of numerous interfering factors related to animals, diets or experimental conditions were tested on the residuals of the response models. The responses of milk FA percentages are also provided. When adjusted to the in vivo variations in the nutrients observed after dietary changes, the effects of the different nutrients were moderate. Finally, this study showed that several of these nutrients could contribute to the changes in milk fat production and composition observed after dietary changes. This is a first step toward predicting milk fat response to changes in nutrient supply.

A total of 161 bulls from 11 breeds were used to generate crossbred calves from Angus cows in 1973 to 1977 at each of three diverse New Zealand locations, and from Hereford cows at one of the locations in the same years. The bulls comprised four local breeds, Angus, Friesian, Hereford, and Jersey, and seven recently imported breeds, Blonde d'Aquitaine, Charolais, Chianina, Limousin, Maine Anjou, Simmental and South Devon. This paper reports the reproductive and maternal performance of the straightbred and first-cross cows over the first four calvings, with first mating as yearlings at 14 to 16 months of age. A total of 7575 mating records from 2109 cows were analysed. Location differences were greater for reproduction than for growth traits and resulted in genotype × environment interactions for some components of cow performance and particularly the composite traits, weight of calf weaned per cow joined (productivity) and cow ‘efficiency’ (the ratio of productivity to cow weight). At all locations the Friesian-cross cows weaned the greatest weight of calf per head but were matched or surpassed by the lighter Jersey crosses in terms of efficiency of calf production. Most of the European crosses performed relatively much better in the most favourable environment than in the harsh environment and this was particularly marked for the productivity of Simmental crosses. Heterosis as a proportion of the purebred mean was important for cow performance and particularly pregnancy rate (0·12), productivity (0·21) and the efficiency ratio (0·16). Heritabilities for weight and age at puberty were both 0·34 (s.e. 0·08). Repeatabilities and heritabilities for cow reproductive traits were low (0·0 to 0·10) but higher for calf weights up to weaning as a trait of the cow (0·09 to 0·38). In general, the large European breeds which excelled in growth and carcass production produced female progeny which reached puberty at greater ages, had lower reproductive performance (especially in less favourable environments) and larger mature size. Some breed utilization strategies to achieve trade-offs between these genetic antagonisms are discussed.

Trends in milk production, calving rates, and survival were monitored on a potential 5580 primiparous and multiparous Holstein-Friesian dairy cows across 14 Irish seasonal spring-calving dairy farms between the years 1990 and 2001. Over this period calving rate to first service (CALV1) reduced by 0·96% per year (55 to 44%; P< 0·001), calving rate to first and second service (CALV12) reduced by 0·84% per year ( 77 to 70%; P< 0·001) and herd average parity number reduced by 0·10 lactation per year (4·3 to 3·5; P<0·001). The proportion of North American Holstein Friesian (NAHF) genes in the cows increased by 5·5% per year (8 to 63%; P<0·001), while pedigree index for milk yield (PIMILK) of the cows increased by 25 kg per year ( P<0·001). The predicted difference of the sires of the cows for calving interval and survival increased by 0·5 days (P<0·001) and reduced by 0·12% ( P<0·001) per year, respectively. A negative association was found between increased phenotypic milk yield, NAHF and PIMILK and reduced calving rates as assessed by CALV1 and CALV12. Increased proportion of NAHF genes exhibited a negative effect on survival ( P<0·001) whereas increased levels of heterosis had a positive impact on survival ( P<0·001). The results of the present study indicate that in seasonal calving herds in Ireland a need for direct selection on traits related to fertility and survival is required to arrest and reverse the declining trends in calving rates and survival.

Behavioural adaptation of farm animals to environmental changes contributes to high levels of production under a wide range of farming conditions, from highly controlled indoor systems to harsh outdoor systems. The genetic variation in livestock behaviour is considerable. Animals and genotypes with a larger behavioural capacity for adaptation may cope more readily with varying farming conditions than those with a lower capacity for adaptation. This capacity should be exploited when the aim is to use a limited number of species extensively across the world. The genetics of behavioural traits is understood to some extent, but it is seldom accounted for in breeding programmes. This review summarizes the estimates of genetic parameters for behavioural traits in cattle, pigs, poultry and fish. On the basis of the major studies performed in the last two decades, we focus the review on traits of common interest in the four species. These concern the behavioural responses to both acute and chronic stressors in the physical environment (feed, temperature, etc.) and those in the social environment (other group members, progeny, humans). The genetic strategies used to improve the behavioural capacity for adaptation of animals differ between species. There is a greater emphasis on responses to acute environmental stress in fish and birds, and on responses to chronic social stress in mammals.

The synthetic disaccharide lactulose is known to improve the intestinal microflora by stimulating the growth of selected probiotic bacteria in the gut. In our experiment the effects of lactulose in combination with the probiotic bacteria Enterococcus faecium on growth performance and morphology of the bovine intestine were examined. Calves aged 39 ± 2 days were randomised to three feeding groups (no. = 14 each group): control (L0), fed milk replacer (MR) containing E. faecium; a lactulose group (L1) containing additional 1% lactulose and a second lactulose group (L3) containing 3% lactulose dry matter. The calves were weighed weekly. After 19 weeks the calves were slaughtered and tissues were collected for histological studies. The average daily live weight gain tended to be higher (P < 0.1) for L3 (1350 g/day) than L0 (1288 g/day). Compared with L0, a reduction (P < 0.001) of ileal villus height due to lactulose treatment of approximately 14% in group L1 and 20% in L3 was determined. A significant decrease in the depth of the crypts about 12% in L1 and 8% in L3 was detected in the caecum. The surface area of lymph follicles from Peyer's patches was decreased by lactulose treatment. Results show that lactulose has an effect on the morphology of intestine. A significant effect on growth performance can not be confirmed. However, results permit the conclusion that lactulose feeding has the tendency to increase growth performance.

This paper presents an analysis of nematode faecal egg counts from Scottish Blackface ewes facing mixed, natural nematode infections (predominantly Teladorsagia circumcincta). The data set comprised 1445 measurements on 421 ewes taken at 4 and 6 weeks post-lambing, over a 4-year period. The ewes, themselves, were the progeny of 73 sires and 285 dams. Only Strongyle eggs were consistently present, and faecal egg counts from this genera ranged from zero (0·4 of all measurements) to 3388 eggs per g. Faecal egg counts were significantly affected by the number of lambs reared and suckled (increasing reproductive burden led to higher counts) by ewe age (older ewes had lower counts) and by previous selection history (ewes from a line previously selected for increased carcass fatness had lower faecal egg counts than ewes from a conversely selected lean line). The heritability of log-transformed faecal egg counts was 0·23 (s.e. 005) and the repeatability, including both within- and between-year permanent environmental effects, was 0·25 (s.e. 004). The apparent presence or absence of infection had a heritability of 015 (s.e. 007) on the observed scale and 0·39 (s.e. 016) when analysed as a binomial threshold trait. The genetic correlation between average 4-week weight of lamb suckled by the ewe and faecal egg counts was 0·24 (s.e. 010). The results suggest that faecal egg counts during early lactation are heritable and influenced by the reproductive performance of the ewe. Selection to reduce nematode faecal egg output from ewes during this period should be successful in reducing pasture larval contamination.

Free-range laying hen systems are increasing within Australia. The pullets for these systems are typically reared indoors before being provided first range access around 21 to 26 weeks of age. Thus, the rearing and laying environments are disparate and hens may not adapt well to free-range housing. In this study, we reared 290 Hy-Line® Brown day-old chicks divided into two rooms each with feed, water and litter. In the enriched room, multiple structural, manipulable, visual and auditory stimuli were also provided from 4 to 21 days, the non-enriched room had no additional objects or stimuli. Pullets were transferred to the laying facility at 12 weeks of age and divided into six pens (three enriched-reared, three non-enriched-reared) with identical indoor resources and outdoor range area. All birds were first provided range access at 21 weeks of age. Video observations of natural disturbance behaviours on the range at 22 to 23 and 33 to 34 weeks of age showed no differences in frequency of disturbance occurrences between treatment groups (P=0.09) but a decrease in disturbance occurrences over time (P<0.0001). Radio-frequency identification tracking of individually tagged birds from 21 to 37 weeks of age showed enriched birds on average, spent less time on the range each day (P<0.04) but with a higher number of range visits than non-enriched birds from 21 to 24 weeks of age (P=0.01). Enriched birds accessed the range on more days (P=0.03) but over time, most birds in both treatment groups accessed the range daily. Basic external health scoring showed minimal differences between treatment groups with most birds in visibly good condition. At 38 weeks of age all birds were locked inside for 2 days and from 40 to 42 weeks of age the outdoor range was reduced to 20% of its original size to simulate stressful events. The eggs from non-enriched birds had higher corticosterone concentrations following lock-in and 2 weeks following range reduction compared with the concentrations within eggs from enriched birds (P<0.0001). Correspondingly, the enriched hens showing a greater increase in the number of visits following range area reduction compared to non-enriched hens (P=0.02). Only one rearing room per treatment was used but these preliminary data indicate 3 weeks of early enrichment had some long-term effects on hen ranging behaviour and enhanced hen’s adaptability to environmental stressors.

Thirty-two Friesian cows in early lactation were divided into four treatment groups to receive ad libitum a mixed diet consisting of silage (0·70) and grain-based concentrate (0·30). Fish meal was subsequently mixed into the diet at levels of 0, 40, 80 and 120 g/kg to provide crude protein concentration (g/kg dry matter) in the complete diets of 156, 181, 200 and 212 respectively. In the 2nd week after calving the yields of fat-corrected milk (FCM) were 28·5, 29·2, 32·0 and 34·9 kg/day for the four levels respectively; at this time, food intake was sufficient only to meet the calculated energy requirement for 15 kg FCM per day. Due to recurring problems with ketosis on the diet containing 120 g fish meal per kg, this treatment was terminated and the experiment continued for 15 weeks with the groups receiving 0, 40 and 80 g/kg fish meal supplements. During this time average yields of FCM were 23·5, 25·6 and 28-0 kg FCM per day respectively and energy intakes were calculated to be sufficient to meet the requirement for 18 kg FCM per day.

It appeared possible to increase milk yield by stimulating fat mobilization through giving undegraded protein supplements to underfed cows in early lactation. However, when an excessive mobilization occurred with a high supplement, and when the animals were yielding 15 to 20 kg FCM more than their metabolizable energy intake was calculated to sustain, some cows became ketotic.

In cattle artificial insemination plays not only a vital role in the successful establishment of pregnancy, which is a prerequisite for initiation of the subsequent lactation, but also in accelerating genetic improvement and facilitating the distribution of semen from genetically elite sires. The latter has been greatly facilitated by the ability to successfully cryopreserve semen. The objective of an insemination is to ensure that there is an adequate reservoir of competent, capacitated, motile sperm in the caudal region of the oviductal isthmus, the site of the main sperm reservoir in the cow, at the time of ovulation to ensure fertilisation. Handling of semen, particularly the 0.25 ml straw, is critically important. Thawed semen needs to be protected from cold and heat shocks and inseminated within 6 to 8 min of thawing. Uterine horn insemination give a modest improvement in conceptions rates particularly in situations where conception rates are low following uterine body inseminations. Most of the studies that evaluated heterospermic insemination were conducted on fresh semen only, and many lacked adequate replication. Consequently, it is difficult to deduce if there are real benefits from using heterospermic semen. While the interval from oestrous onset to time of ovulation would appear to be similar for cows and heifers at about 28 h there is huge variation (standard deviations of 5 to 6 h) around this average. While best conception rates are achieved when cows are inseminated from mid oestrus to a few hours after the onset of oestrus, this is difficult to achieve in practice. There is emerging evidence that having one insemination time, when all cows requiring insemination in the herd on that day are inseminated, does not compromise fertility provided insemination technique is good and the semen used is of high fertility.