This study compared the effect of supplementing maize stover (MS) with cowpea (Vigna unguiculata) haulms or commercial concentrate (CC) on feed intake, nutrient digestibility, live weight gain and carcass yield of male Ethiopian Highland sheep. Two cowpea genotypes, 12688 (forage) and IT96D-774 (dual-purpose), were used. A randomised block design was applied with groups of eight sheep, blocked by weight, allocated to one of six treatments; MS ad libitum either unsupplemented or supplemented daily with 150 or 300 g dry matter (DM) of either cowpea or CC. MS contained more neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin than either cowpeas or CC. Crude protein (CP) content of the forage-type cowpeas was higher than either dual-purpose or CC, while MS had the lowest CP content. Relative to the negative control group, cowpea at either level significantly (P < 0.01) increased both MS intake and total NDF and lignin. Supplementation significantly (P < 0.01) increased nitrogen (N) intakes relative to the negative control, with N intake for CC and dual-purpose cowpea (high level) being similar to the intakes for cowpeas at 150 g. N intake with the forage-type cowpea offered at higher levels was significantly (P < 0.01) greater than the other groups. No significant differences (P > 0.01) in MS intake were identified between cowpeas at either level or CC and, although intake level of CC increased, it did not differ significantly from the negative control group. Supplementation significantly (P < 0.01) improved average daily gain, with the negative control group losing weight over the experimental period, and increased final live weight, carcass cold weight and dressing percentage. Supplementation significantly improved the apparent digestibility of DM, organic matter and NDF, with no significant difference found between cowpeas at either level. N retention was negative for sheep offered only MS, but positive with all supplements, with cowpeas improving N retention to a greater extent than CC. Interestingly, N retention/N intake was higher with cowpeas offered at the lower level suggesting an improvement in utilisation efficiency. The results indicate that the supplementation of MS with cowpea enhanced ruminant production through improvements in digestibility and intake. Further, as production improvements associated with the two levels of supplementation did not differ significantly, it is suggested that where limited quantities of cowpea are available, it may be of greater nutritional benefit to offer smaller quantities over an increased number of animal days.

Generally, once-daily milking (ODM) decreases milk yield. This effect may be the consequence of a decrease in mammary epithelial cell (MEC) activity or a reduction in their number. The aim of this study was to determine the effect of ODM on the synthetic activity and rate of apoptosis of MEC using a non-invasive method. Eight Alpine goats were subjected to ODM or twice-daily milking for two 5-week periods. MECs were purified by centrifugation and immunocytochemical binding in milk after 1 and 5 weeks of each period. mRNA levels of some proteins involved in lactose and milk protein synthesis and in apoptosis were evaluated using real-time PCR. Isolation of MEC from milk was a useful method to investigate transcriptional regulation in a timeline study. ODM induced greater decreases in milk, lactose and protein yields after 1 week than after 5 weeks. This suggests an adaptation of the mammary gland to ODM, which reduces the inhibitory effect of this practice. Reductions in milk component yields were associated with lower α-lactalbumin transcripts, suggesting a transcriptional decrease of lactose synthesis during ODM. Glucose transporter GLUT1 transcripts were downregulated under ODM, suggesting that lactose precursor uptake by MEC might be involved in the regulation of lactose synthesis. κ-Casein mRNA levels tended to be lower during ODM. ODM increased levels of the pro-apoptotic transcript Bax after both 1 and 5 weeks, but no variation was observed in the Bax/Bcl-2 ratio. ODM affected cell synthetic activity through transcriptional regulation and may have induced apoptosis. The reduction of the negative effect of ODM on milk yield suggests that Alpine goats are able to adapt to ODM. Further studies are needed to investigate the effect of ODM on MEC turnover.

This study aimed to investigate the effect of supplemental camphor on the performance and immune functions of Japanese quail by feeding graded levels (0 (control), 250, 500, 750, 1000, 5000 or 10 000 ppm) of camphor during a 42-day feeding trial. In all, 280 1-day-old quail chicks were randomly assigned into 28 cages of 10 chicks each with separate feeders. The results clearly demonstrated that camphor did not have a significant effect on BW, BW gain, total experimental average daily feed intake, feed conversion ratio, internal organ relative weights and biochemical parameters such as uric acid, albumin, total protein and triglyceride; however, plasma cholesterol concentration was significantly different in a linear manner, in which 500 ppm of camphor resulted in a lower level of cholesterol. Alternatively, greater concentrations of glucose and high-density lipoprotein (HDL) were also found in 5000 and 1000 ppm of camphor groups, respectively. Cellular responses to the phytohaemagglutinin-P and 2,4-dinitro 1-chlorobenzene skin test were not influenced by dietary camphor. Humoral responses to secondary sheep red blood cells, avian influenza virus (AIV) and Newcastle disease virus (NDV) immunisations were positively influenced by camphor supplementation, in which greater secondary response to sheep erythrocytes belonged to 750 and 1000 ppm of camphor groups; whereas, diet supplementation with camphor had no significant effect on lymphoid organ weights and heterophil-to-lymphocyte ratio. The greatest AIV antibody titers were seen in groups, which received 1000 and 5000 ppm of camphor (P<0.05) and the values of NDV antibody titers increased with an increase in the camphor consumption. Furthermore, dietary inclusion of 500 ppm of camphor positively decreased coliform populations in the gastrointestinal tract (GIT). In addition, an increase in lactic acid bacteria was also observed in quails, which were fed on the diets containing 750 ppm camphor. Collectively, these data suggest that as a phytogenic feed additive, camphor may effectively act as a modulator of health status (by increasing glucose and HDL), GIT microbiota and immunological responses of the Japanese quail.

Nitrogen balance was measured in a series of experiments to determine the optimum balance between lysine, threonine and methionine plus cystine by successive additions of the free amino acids to a basal diet of barley, soya bean meal and tallow. The basal diet had a calculated digestible energy (DE) value of 14·5 MJ/kg and a crude protein content of 146 g/kg. The ranges of total lysine; threonine and methionine plus cystine tested were (g/kg) 6·6 to 11·8, 4·9 to 6·9 and 4·3 to 71, respectively. Latin-square designs were used involving a total of 33 pigs. Nitrogen utilization was optimized in pigs of 3 to 9 weeks of age when each kg of diet contained 10·5 g lysine, 6·4 g threonine and 5·0 g methionine plus cystine, corresponding to a ratio of 100: 61: 48. Thereafter, five diets were formulated in which the same ratio was maintained, but at different protein levels (129 to 192 g/kg). Again the diets were based on barley, soya bean meal and tallow supplemented with free amino acids. These diets were compared, in both nitrogen balance and performance experiments, with a conventional early-weaning diet with a protein content of 240 g/kg. All six diets had the same calculated DE value (14·5 MJ/kg). The N balance experiment was of Latin-square design and involved 18 pigs, and the performance experiment used 36 pigs fed individually from 3 to 9 weeks of age. A diet containing 0·99 g lysine per MJ DE (14·4 g lysine and 192 g balanced protein per kg) was considered to be adequate on the basis of the growth rate and food conversion efficiency results obtained.

Intakes and feeding patterns were studied in two groups of 24 Scottish Blackface ewes, with initial mean body condition scores of 2·15 (thin) and 3·15 (fat). Three treatments, allowing access to a dried-grass pellet diet ad libitum for 6, 12 or 24 h/day, were applied in a Latin-square design, with each sheep receiving each treatment for one 12-day period. Food intakes were measured daily and feeding activity was recorded automatically every minute for one 24-h period during the last 5 days of each 12-day treatment period.

Mean intakes were higher for thin than for fat ewes (1720 v. 1467 g dry matter (DM) per day; P < 0·001). There were no interactions between the effects of body condition and food access time and mean intakes over the last 7 days for the 6-, 12- and 24-h food access treatments were 1429, 1686 and 1805 g DM per day respectively (T < 0·001). Time spent feeding was higher for thin than for fat ewes, over the whole day (231 v. 197 mini day; P < 0·05) and in the first 6 h after the introduction of fresh food (140 v. 120 min; P < 0·05), but there were no differences between thin and fat ewes in the frequency of meals or in the rate of intake during meals. Intakes for the first 6 h were higher with restricted food access (1402, 1109 and 819 g DM per day for 6-, 12- and 24-h access; P < 0·001) but there were no differences in time spent feeding. The number of meals during the first 6 h was higher (10·4 v. 8·3; P < 0·05) and the rate of intake was higher (11·4 v. 7·8 g/min; P < 0·05) for 6-h compared with 24-h food access.

It was concluded that long-term differences in intake due to body condition and short-term changes due to restricting food access time, involve different behavioural responses and this may reflect differences in the mechanisms involved in the regulation of voluntary intake. Keywords: body condition, feeding behaviour, sheep.

Twenty-four indigenous goats suckling either single (male or female) or twin kids were traditionally reared during a 32-week lactation period. During the suckling period of 12 weeks, milk production was estimated at 7-day intervals. During the milking period the goats were hand-milked twice daily and their milk production was measured at 4-week intervals. Milk samples were analysed for fat, protein, lactose, ash and dry matter concentration and solids-not-fat and energy concentration were calculated. During lactation, the goats were weighed at regular intervals and their body-condition score assessed at each weighing.

Goats with twins produced more milk than did those with singles during the suckling period but not after weaning. Peak yield occurred between the 10th and 11th week of lactation. Yield declined rapidly after weaning at 12 weeks and then decreased gradually from 16 to 32 weeks. The sex of the single kids had no effect on lactation yield. Milk composition was not affected by the number or sex of the kids suckled. Fat, protein and ash concentration fell during the 1st month of lactation and thereafter showed a gradual rise. Lactose concentration fell gradually after the 2nd month. Both live weight and body condition of the goats increased continuously throughout lactation.

Improving immune status in neonates is crucial to health and production. Gut active carbohydrates (GAC) have been associated with increasing immunoglobin levels and immonucompetence development in mammals. The objective of the following studies was to evaluate whether GAC (mannan-oligosaccharides) applied orally to progeny immediately following parturition, improved blood plasma immunoglobulin (Ig) type G concentrations in piglets and calves. Three trials were conducted comparing control groups with those receiving GAC orally. The first two trials used piglets that were monitored for blood IgG at 2 days of age and for changes in body weight (BW), and the third trial monitored calf IgG from birth to 21 days of age. Piglets in the experimental group received 0.75 g GAC in 10 ml saline at birth and 24 h of age. The calf trial compared the control group against calves that received 22.5 g GAC mixed into 4.5 l of colostrum (to give 5 g/l) in the first 24 h after parturition. Blood serum samples were taken at 2 days post partum in piglets, and at several time points from 6 h to 21 days of age in calves, and were analysed for IgG levels by radial immunodiffusion. In the first piglet trial, significantly higher levels (32%) of IgG were observed for piglets fed GAC (P < 0.001), and in the second, IgG concentration was elevated by 23% (P < 0.01) and BW increased by 9% (P = 0.023) with GAC supplementation. Significant improvements for calves were recorded at all time points in those fed GAC (P < 0.05), with an increase in serum IgG observed after the first day, which was maintained throughout the sampling period, resulting in a difference of 39% at the end of the trial (21 d). These findings form a basis for further studies, which are required to investigate possible modes of action involved in enhancing blood immunoglobulin concentrations in young animals, and the longer-term effects this may have on the development of the immune response.

There is strong evidence that the gonads modulate the hypothalamic–pituitary–adrenal axis. To investigate these sex differences at the adrenal glands of sheep we compared the cortisol response to ACTH (experiment 1) and measured the relative expression of oestrogen receptor alpha (ERS1), androgen receptor (AR), melanocortin 2 receptor (MC2R) and steroid acute regulatory protein (STAR) mRNA in adrenal glands (experiment 2) of gonadectomised rams and ewes either with or without sex steroid replacement. In experiment 1 six castrated adult rams and four ovariectomised adult ewes were used in two ACTH trials. On each trial blood samples were taken every 15 min for 4 h through an indwelling jugular catheter and each animal received 0.5 mg of an ACTH analogue i.v., immediately after the sample at 1 h from the beginning of the trial. Four days after the first trial the males received 100 mg of Testosterone Cyclopentilpropionate (TC) i.m. and the females received 2.5 mg of Oestradiol Benzoate (EB) i.m. At 72 h after TC or EB administration the second trial was performed. In experiment 2 the adrenal glands were obtained from gonadectomised adult rams (n=8) and adult ewes (n=8). Four rams received 100 mg of TC i.m. and four females received 0.5 mg of EB i.m. Blood samples were taken at 0, 12, 24, 48 and 72 h relative to steroid replacement and the animals were thereafter slaughtered. Cortisol, testosterone and 17β-oestradiol were determined by radioimmunoanalysis. The transcripts of ERS1, AR, MC2R and STAR were determined by real-time reverse transcription PCR in adrenal tissue. Cortisol secretion was higher in female sheep than in male sheep, and higher in EB-treated than non-treated ewes. No difference in cortisol secretion was observed between TC-treated and non-treated rams. Gonadectomised rams treated with TC presented greater AR mRNA and MC2R mRNA expression than males without the steroid replacement. Gonadectomised ewes treated with EB tended to present lower AR mRNA than the ones without steroid replacement. Gonadectomised rams with TC also had greater AR mRNA, ERS1 mRNA and MC2R mRNA expression than ewes treated with EB. The relative amount of STAR transcript was not different among the different groups. The results confirm sex differences in ACTH-induced cortisol secretion in sheep, as well as in the expression of the receptor proteins for both 17β-oestradiol and testosterone in the sheep adrenal gland. However, the underlying mechanisms for sex steroid modulation remain unresolved.

One hundred and twenty eight gilts by Landrace sires out of Large White × Landrace females were allocated on the basis of litter relation-ship and initial weight to 16 treatments involving the individual feeding of four dietary protein levels (approximately 15%, 18%, 21% and 24% CP) at each of four energy levels (2830, 3100, 3375 and 3585 kcal DE/kg air-dry feed). Amino acid balance (as% of total CP) was maintained relatively constant, using synthetic lysine and methionine where necessary. Growth performance was measured over a live-weight range of 23 kg to 59 kg, at which latter weight the pigs were slaughtered for carcass evaluation by dissection of the middle ‘joint’ from a half carcass. Linear carcass measure-ments were also taken. There was a significant energy × protein interaction only for killing-out percentage; for all other measures the main effects could be assessed independently. Increase in dietary energy value gave linear increase in growth rate (GR) and improve-ment in efficiency of feed conversion (EFC), accompanied by linear decrease in lean percentage and increase in fat percentage. Increase in dietary protein level gave an increase in GR and improvement in EFC with the first increment (from 15% to 18% CP), but depressions in both these characteristics with the final increment (from 21% to 24% CP). Lean percentage increased and fat percentage decreased with the first protein increment, with no further significant changes. Calculation of daily rates of tissue deposition indicated that maximum rate and efficiency of fat-free carcass gain could be attained with the second lowest energy and protein levels tested (i.e. 3106 kcal DE/kg and 18·2% CP).

Using whole-genome sequence (WGS) data are supposed to be optimal for genome-wide association studies and genomic predictions. However, sequencing thousands of individuals of interest is expensive. Imputation from single nucleotide polymorphisms panels to WGS data is an attractive approach to obtain highly reliable WGS data at low cost. Here, we conducted a genotype imputation study with a combined reference panel in yellow-feather dwarf broiler population. The combined reference panel was assembled by sequencing 24 key individuals of a yellow-feather dwarf broiler population (internal reference panel) and WGS data from 311 chickens in public databases (external reference panel). Three scenarios were investigated to determine how different factors affect the accuracy of imputation from 600 K array data to WGS data, including: genotype imputation with internal, external and combined reference panels; the number of internal reference individuals in the combined reference panel; and different reference sizes and selection strategies of an external reference panel. Results showed that imputation accuracy from 600 K to WGS data were 0.834±0.012, 0.920±0.007 and 0.982±0.003 for the internal, external and combined reference panels, respectively. Increasing the reference size from 50 to 250 improved the accuracy of genotype imputation from 0.848 to 0.974 for the combined reference panel and from 0.647 to 0.917 for the external reference panel. The selection strategies for the external reference panel had no impact on the accuracy of imputation using the combined reference panel. However, if only an external reference panel with reference size >50 was used, the selection strategy of minimizing the average distance to the closest leaf had the greatest imputation accuracy compared with other methods. Generally, using a combined reference panel provided greater imputation accuracy, especially for low-frequency variants. In conclusion, the optimal imputation strategy with a combined reference panel should comprehensively consider genetic diversity of the study population, availability and properties of external reference panels, sequencing and computing costs, and frequency of imputed variants. This work sheds light on how to design and execute genotype imputation with a combined external reference panel in a livestock population.

In summer 1973, the sheep farmer in most parts of the Irish Republic could telephone his local cattle Artificial Insemination (AI) station and ask for a technician to treat his ewes for ‘early-lamb’ (December/January) production with intravaginal sponges and pregnant mare's serum gonadotrophin (PMSG). The 60 p per ewe service, which first became available at that time, covered two visits by the technician: the first to insert sponges; the second, 14 days later, to withdraw them and administer the gonadotrophin. On the basis of considerable experimental evidence, the farmer could expect about 60 to 70% of ewes treated to conceive to first services and lamb within a short period of each other, and some 80% to produce offspring to the combined first and second services. The scheme, based on natural service, was used by several hundred farmers in that first year of operation, and was made available on a similar basis again in 1974. The introduction of this cheap, effective and simple technique for the hormonal control of reproduction in sheep was the result of considerable activity over the years by Dr Sean Crowley and his staff in An Foras Taluntais and various workers in University College, Dublin (UCD). Due credit must be given, however, to the Irish Department of Agriculture, which sponsored extensive field testing of controlled breeding techniques in 197/172, and subsequently arranged with cattle AI stations to provide countrywide coverage on a fee per ewe basis from 1973.

On the basis of the isomer-specific effects of trans fatty acids (FA) on human health, and the detrimental effect of t10,c12-conjugated linoleic acid (CLA) on cows’ milk fat production, there is a need to identify factors that affect the shift from trans-11 to trans-10 pathway during ruminal biohydrogenation of FA. This experiment was conducted in vitro and aimed at separating the effects of the diet of the donor cows from those of the fermentative substrate, which is necessary to prevent this shift. A total of four dry Holstein dairy cows were used in a 4 × 4 Latin square design. They received 12 kg of dry matter per day of four diets based on maize silage during four successive periods: the control diet (22% starch, <3% fat); the high-starch diet, supplemented with wheat plus barley (35% starch, <3% crude fat); the sunflower oil diet, supplemented with 5% of sunflower oil (20% starch, 7.6% crude fat); and the high-starch plus oil diet (33% starch, 7.3% crude fat). Ruminal fluid of each donor cow was incubated for 5 h with four substrates having similar chemical composition to the diets, replacing sunflower oil by pure linoleic acid (LA). The efficiency of isomerisation of LA to CLA was the highest when rumen fluids from cows receiving dietary oil were incubated with added LA. The shift from trans-11 to trans-10 isomers was induced in vitro by high-starch diets and the addition of LA. Oil supplementation to the diet of the donor cows increased this shift. Conversely, the trans-10 isomer balance was always low when no LA was added to incubation cultures. These results showed that a large accumulation of trans-10 FA was only observed with an adapted microflora, as well as an addition of non-esterified LA to the incubation substrate.

MC4R (melanocortin 4 receptor) is expressed in the appetite-regulating areas of the brain and takes part in leptin signaling pathways. Sequencing of the coding region of the MC4R gene for 354 yaks identified the following five single nucleotide polymorphisms (SNPs): SNP1 (273C>T), SNP2 (321 G>T), SNP3 (864 C>A), SNP4 (1069G>C) and SNP5 (1206 G>C). SNP1, SNP2 and SNP3 were synonymous mutations, whereas SNP4 and SNP5 were missense mutations resulting in amino acid substitutions (V286L and R331S). Pairwise linkage disequilibrium (LD) analysis indicated that two pairs of SNPs, SNP2 and SNP5 (r2=0.81027) and SNP4 and SNP5 (r2=0.53816), exhibited higher degrees of LD. CC genotype of SNP4, CGACG and CTCCC haplotypes for all SNPs were associated with increased BW of animals that were 18 months old and with the average daily gain. The secondary structure and transmembrane region prediction of the yak MC4R protein suggested that SNP4 was correlated with influential changes in the seventh transmembrane domain of the MC4R protein and with the functional deterioration or even incapacitation of MC4R, which may contribute to the increased feed intake, BW and average daily gain of the yaks with CC genotypes. The data from this study suggested that 1069G>C SNP of the MC4R gene could be used in marker-assisted selection of growth traits in the Maiwa yak breed.

The reproductive performance of 51 Finnish Landrace × Dorset Horn (FD) ewes was compared with that of 50 Border Leicester × Scottish Blackface or Greyface (GF) ewes. Ewes were mated without hormone synchronization in November 1973 and with hormone synchronization in August 1974 and again in February 1975. Conception rates at the three matings were 88, 82 and 73% respectively in FD ewes and 96, 56 and 26% respectively in GF ewes. Mean litter size over three lambings was 2·34 in FD ewes and 2·15 in GF ewes. Stillbirths accounted for 12·0 and 10·2% of all lambs respectively and further lamb deaths during and after birth were 15·2 and 4·3% respectively; 11·6% of live FD lambs and 7·7% of GF lambs were fostered or reared artificially. The losses resulted in mean numbers of lambs weaned per ewe lambing of 1·75 from FD ewes and 1·85 from GF ewes (including lambs from those ewes that were artificially reared). Annual productivity was 2·13 and 1·67 lambs respectively.

Two experiments were conducted to determine the nutritive value of extruded or raw peas (Pisum sativum as an energy and protein supplement for pigs of 33 to 100 kg live weight. Experiment 1 determined the effects of extrusion on the nutrient apparent digestibility of peas when included at 200 g and 400 g/kg in the diet. In experiment 2, performance was determined in individually fed pigs (no. = 70) offered diets ad libitum including a control (no peas, T1), 200 g/kg raw peas (T2), 400 g/kg raw peas (T3), 200 g/kg extruded peas (T4), 400g/kg extruded peas (T5). The peas were extruded at 120°С for 30 s. All diets were formulated to have similar concentrations of digestible energy (DE) and total lysine. There was a significant interaction effect (P < 0·05) between level of peas and extrusion on the digestibility of the organic matter (OM), nitrogen (N), energy and the DE content of the peas. The inclusion of 400 g/kg raw peas led to a lower estimated digestibility of OM (P < 0·001), N (P < 0·001), gross energy (P < 0·05) and DE content (P < 0·05) of the peas compared with the 200 g/kg peas. However, there was no difference (P > 0·05) between the digestibility of the 200 and 400 g/kg peas when the peas were extruded. In experiment 2, there was a significant interaction (P < 0·05) between the level of peas in the diet and extrusion. As the level of raw peas increased from 200 to 400g/kg, growth rate decreased (P < 0·01) and food conversion ratio (FCR) increased (P < 0·01). However, as the level of extruded peas was increased from 200 to 400g/ kg, there was no difference in either growth rate or FCR. It is concluded that extrusion of peas improved the nutrient digestibility and improved overall gain and FCR of the pigs.

The aim of this experiment was to evaluate the effect of calf management during lactation on dam performance and nursing behaviour. Thirty-six multiparous beef cows (aged 7.5 ± 0.52 years) of Parda de Montaña breed (mean live-weight (LW) at calving 566 ± 9.3 kg) with a moderate body condition (mean 2.6 ± 0.02 on a 1 to 5 scale), were assigned to three nursing frequencies from the day after parturition: Once-daily restricted nursing during a 30 min period at 0800 h (RESTR1), twice-daily restricted nursing during two 30 min periods at 0800 and 1530 h (RESTR2) and ad libitum nursing (ADLIB). Cows were fed throughout the experiment 80 MJ/day of metabolizable energy. Cow–calf behaviour recordings were performed on days 30 and 66 of lactation in each treatment. Blood samples were collected fortnightly to analyse non-esterified fatty acids (NEFA) by an enzymatic colorimetric method, and twice weekly to determine progesterone concentrations by radioimmunoassay. Cow LW losses (P < 0.05), fat-corrected milk yield (P < 0.05) and calf average daily gain (P < 0.01) during lactation were higher in ADLIB. Nursing frequency affected the mean serum concentrations of NEFA, being lower in RESTR1 (0.18 mmol/l; P < 0.05) than in RESTR2 and ADLIB cows (0.29 and 0.25 mmol/l, respectively). The highest occurrence of nursing bouts was observed in ADLIB, leading to greater nursing duration per day (not statistically compared) in this treatment (58.8 ± 5.84 min) than in their restricted nursing counterparts (22.2 ± 1.42 and 34.3 ± 1.16 min, in RESTR1 and RESTR2, respectively). The nursing system did not affect the proportion of cows cycling within 3 months post partum (58%, 46% and 55% in RESTR1, RESTR2 and ADLIB, respectively; P > 0.05). The majority of cows in all treatments showed a short oestrus cycle after first ovulation (75%, 100% and 83%; P > 0.05). In conclusion, the post-partum luteal function in cows managed under continuous access to calves was similar to restricted nursing frequencies, despite the greater suckling intensity of the formers. Restricting calf presence does not enhance the resumption of ovarian activity when suckler cows are managed in moderate nutritional conditions.

Post-weaning metabolizable energy intake, growth of empty-body chemical components and efficiencies of energy utilization were evaluated for Hereford intact males (17) and females (16) and Simmental intact males (15) and females (16) during a 212-day feeding period. Within each breed × sex subclass, animals were assigned to one of three levels of metabolizable energy (ME) intake: (1) 544 kJ/kg M0·75 per day, (2) 795 kJ/kg M0·75 per day, and (3) ad libitum. Body composition of each animal was estimated at the beginning and end of the feeding period by deuterium oxide dilution.

Protein and water gain of Hereford and Simmental cattle were similar at restricted levels of intake but were greater for Simmental than for Hereford cattle at ad libitum intakes. Similarly, rates of protein and water gain tended to increase more rapidly in response to increased energy intake by males than by females. Hereford males gained fat and energy slightly more rapidly than Hereford females, but Simmental males gained fat and energy at slower rates than Simmental females.

Males had higher maintenance requirements and tended to use ME with less efficiency for maintenance and gain than females. Hereford cattle had lower maintenance requirements and used ME with greater efficiency for both maintenance and gain than Simmental cattle.

Precision feeding requires a mathematical model to estimate standardized ileal digestible (SID) lysine (Lys) requirements (SIDLysR) in real time. However, this type of model requires constant calibration updates. The objective of this study was to review the calibration of the model used to estimate the real-time Lys requirements of individual growing-finishing pigs. A digestibility trial (n = 10) was conducted to evaluate amino acids digestibility during the growing and finishing phases. Additionally, 120 pigs were used in two 28-day growth experiments conducted as completely randomized design with growing (25 ± 2.1 kg BW, n = 60; 10 pigs per treatment) or finishing barrows (68.1 ± 6 kg BW, n = 60; 10 pigs per treatment). In each experiment, the pigs were divided into six equal treatment groups and fed 60%, 70%, 80%, 90%, 100% or 110% of their estimated individual SIDLysR. The Lys requirement of each pig was estimated daily using a real-time model. Body composition was measured with dual-energy X-ray densitometry on day 1 and 28 of the experiments. Average daily feed intake increased quadratically (P < 0.05) during both growth phases. Maximum average daily gain (ADG) (0.98 kg) and maximum protein deposition (PD; 170 g/day) were observed in growing pigs fed 100% of the estimated SIDLysR (P < 0.001). During the growing period, PD in BW gain (17% to 19%) and N efficiency (52% to 65%) increased linearly (P < 0.01) with increasing inclusion rates of SID Lys. Finishing pigs had maximum ADG (1.2 kg/day) when they were fed 100% of the requirements. However, the amount of protein in BW gain (13% to 16%) and N efficiency (40% to 55%) increased linearly (P < 0.01) with increasing inclusion rates of SID Lys. In conclusion, the model proposed for precision feeding is correctly calibrated to predict SIDLysR that maximize PD and ADG of average pigs from 25 to 50 kg BW. Still, there is an opportunity to improve the estimation of SIDLysR and N retention in individual pigs by better representing the individual proportion of protein in BW gain and the factors controlling the efficiency of Lys utilization in individual pigs.

Preweaning mortality in piglets is a welfare issue, as well as an ethical and economic concern in commercial pig farming. Studying the causes of preweaning mortality and their prevalence is necessary to reduce losses. Preweaning piglet mortality was investigated in a field study including 347 sows from 14 loose-housed Norwegian piglet-producing herds. A total of 5254 piglets were born in these herds during the study period, and 1200 piglets were necropsied. The cause of death was based on pathoanatomical diagnosis (PAD). Preweaning mortality of all piglets in the study was 23.4%, including 6.3% stillborn. The two main causes of preweaning mortality in live-born piglets (n=4924) were trauma (7.1%) and starvation (2.7%). Piglets dying of an infection accounted for 2.0%. Among the necropsied piglets (n=1200), 29.1% had died due to trauma, 26.8% were categorized as stillborn and 11% had died of starvation. Piglets that had died of trauma, had a mean time of death of 1 lactation day (LD 1), ranging from LD 0 to LD 21. The mean time of death of piglets that died due to bacterial infection was LD 9, ranging from LD 0 to LD 31, with Escherichia coli accounting for most infections found in necropsied piglets. Farmers were able to identify death by trauma in piglets, but were less able to identify death due to hunger. Most piglets that died in the preweaning period, died of trauma. Surprisingly, this included large and well-fed piglets. The second most prevalent cause of preweaning mortality was starvation. Improved monitoring may reveal piglets with low body mass index, and additional nutrition may contribute to increase the survival rate.

Due to global climatic changes, water and soil salinization is an increasing worldwide phenomenon, thus creating new threats for farm animal production. The present study was designed to investigate the adaptation capacity of goats towards sodium chloride (NaCl) in drinking water. Twelve non-pregnant Boer goats with an average body weight of 50.5 ± 9.0 kg were kept in individual pens. The study was conducted in four phases applying a two-choice preference test. In the control phase (phase 1) only fresh water was supplied in two containers. In phase 2, water with different salt concentrations (0.25%, 0.5%, 0.75%, 1.0%, 1.25% and 1.5%) was offered in one container and tap water in the other (sensitivity test). During the third phase (adaptation), goats were stepwise habituated to saline water by offering only saline water with different increasing concentrations (between 0% and 1.5% NaCl) in both containers. Subsequently, in phase 4 (sensitivity re-test) the same treatment as in phase 2 was repeated. Goats had ad libitum access to hay, water and a mineral licking block. Individual water and feed intake were recorded daily, while body weight and body condition score were measured every 2nd week. Body weight was not affected by saline water intake, whereas dry matter intake and body condition scores decreased significantly during the experiment. Water intake was significantly (P<0.001) higher in phase 2 (sensitivity test) and phase 3 (adaptation), compared to phase 1 (control) and phase 4 (sensitivity re-test). Total sodium intake followed the same pattern. In phase 2, when goats had the choice between fresh and saline water for the first time they preferred higher salt concentrations and consumed significantly (P<0.001) higher amounts of saline water (75.4 ± 53.2 g/kg BW0.82 per day) than in the re-test (40.4 ± 34.0 g/kg BW0.82 per day) after the habituation period. Thus, salt discrimination rejection thresholds were lowered to 1.25% in phase 4 compared to 1.5% in phase 2. The results suggest that a stepwise adaptation to saline drinking water in goats is an effective method to habituate the animals to saline water intake when concentrations were below 1.5%. Goats reacted more sensitively to the salinity of drinking water after prolonged exposure to saline water indicating flexible regulation mechanisms depending on the total sodium balance of the animal.