A study of the intake potential of a range of well-preserved silages offered to lambs over several years showed that, of the many parameters considered, those with the greatest positive effect on DM intake were sugars in the grass as ensiled, residual sugars and protein nitrogen in the silage, with ethanol concentration in the silage having a negative effect (Henderson, Anderson and Phillips, 1984). In the experiments reported here ADD-F (85 per cent formic acid) from BP Chemicals International was applied to ryegrass at a rate sufficient to conserve much of the sugar (WSC) in the silage by inhibiting the growth of the micro-organisms on the grass. The initial lowering of the pH should also inhibit the activity of the plant enzymes, conserve protein nitrogen (PN) in the silage and prevent extensive deamination.

In 1986 first-cut perennial ryegrass, and in 1987 Italian/perennial ryegrass, was ensiled direct-cut, untreated or treated with 5 1 ADD-F/t grass in 100t capacity clamp silos. The grass was cut with a mower and lifted with a precision-chop forage harvester. The acid was pumped onto the grass through a dribble bar sited over the pick-up drum.

The aim of this study was to estimate the parameters of the lactation curve of dairy cows in Scotland so as to improve the prediction of milk yield. The data used for deriving the parameters were ‘milk test’ yield values recorded by the Scottish Milk Records Association during a 2-year period. The data were grouped, according to lactation number, breed and area of Scotland, into 27 groups. The data pertaining to each group were then averaged so as to produce by regression analysis a curve for each calving week, lactation number and area. Areas and breeds were found to affect the shape of the lactation curves.

Growth performance and body composition differences between Large White control (C) and 10th generation index-selected (S) pigs were evaluated on a fixed food, fixed time trial. This avoided the complicated interpretation associated with interacting variations in food intake, days on test and body composition. Thirty-nine C and 40 S boars were slaughtered, their carcasses dissected and whole empty bodies minced and chemically analysed after an 84-day trial starting at 26·6 ± 0·27 kg live weight. S boars were older at the start of test (95·2 v. 89·0 days, P < 0·001), were heavier at the end of test (96·2 v. 93·8 kg, P < 001) and converted food more efficiently (0·392 v. 0·378 kg gain per kg food, P < 0·01) than C boars. Bodies of S boars contained more water (48·3 v. 45·9 kg, P < 0·001), less lipid (17·4 v. 18·8 kg, P < 0·001) less gross energy (1 004 v. 1 045 MJ, P < 0·05), but similar amounts of protein (13·8 v. 13·4 kg, NS) compared with C boars. S carcasses contained more lean (34·1 v. 31·8 kg, P < 0·001), less subcutaneous fat (12·5 v. 13·7 kg, P < 0·001), and had lower P2 backfat depths (15·8 v. 18·3 mm, P < 0·001) than C carcasses. Although carcass leanness had been increased, 10 generations of index selection had also reduced the overall energetic efficiency of the selection line, apparently by increasing non-productive heat loss.

Immunity-related traits are heritable in chicken, therefore, it is possible to improve the inherent immunity by breeding programs. In this study using the Illumina chicken 60K single nucleotide polymorphisms (SNPs) chip, we performed a set of genome-wide association studies to determine candidate genes and loci responsible for primary and secondary antibody-mediated responses against sheep red blood cell. A F2 population descended from a commercial meat-type breed and an Iranian indigenous chicken was used for this study. Statistical analysis was based on a mixed linear model utilizing genomic relationship matrix to prevent spurious associations. Correction for multiple testing was done by applying 5% and 10% chromosomal false discovery rates (FDRs) for significant and suggestive thresholds, respectively. Nine significant and 17 suggestive associated SNPs were identified. Most of the SNPs that were suggestively associated with the primary response of total plasma immunoglobulins were also significantly associated with this trait in secondary response. Three SNPs were located within a narrow region of 23 kb on chromosome 16. Pathway analysis for the genes surrounding the associated SNPs showed that they are involve in antigen processing and presentation, primary immunodeficiency, vitamin digestion and absorption, cell adhesion molecules, phagosome, influenza A, folding, assembly and peptide loading of class I major histocompatibility complex, lipid digestion, mobilization, and transport (FDR < 0.1). Interestingly, there were common regains associated with multiple immune-related traits.

The influence of pre-slaughter nutrition on the potency of foetal serum in cell culture was studied. Ewes carrying late-gestation foetuses (120-day gestation) were either fasted for 66 h (F), fasted for 66 h but drenched with Ketol, a propylene glycol preparation, (5 × 120 ml doses; FK), given food ad libitum (A), or given food ad libitum and drenched with Ketol (5 × 120 ml doses; AK). Following slaughter foetal blood was collected for the determination of potency in cell culture using industry-standard cell culture bioassays: cloning efficiency, plating efficiency and a 96 h cell proliferation assay. Foetal serum insulin-like growth factor (IGF) concentrations were also measured. Pre-slaughter fasting or drenching with Ketol had no effect on the potency of foetal serum in any of the cell culture bioassays. Fasting significantly lowered foetal plasma IGF-1 levels (F < 0·01). Foetal IGF-2 levels were unaffected by fasting or drenching with Ketol.

Eight pregnant beef cows and four rumen-fistulated cows were given 1·67 kg barley dry matter per day and 5·1 kg chopped oat straw dry matter treated by one of four different methods. The straw treatments (given in a 4 × 4 Latin square design) were (A) nil, (B) sodium hydroxide (25 g/kg straw, dry matter basis), (C) a fully soluble liquid supplement containing urea, calcium, phosphorus, sodium, trace elements and vitamins (40 g/kg straw, dry matter basis), and (D) sodium hydroxide plus liquid supplement. In the absence of liquid supplement 0·3 kg per day of the straw dry matter was not consumed, and with the sodium hydroxide plus liquid supplement treatment the cows would have consumed more straw than was offered. Sodium hydroxide increased the digestibility of the straw organic matter from 0·46 to 0·50 (P <0·05), and this was further increased to 0·53 (P <0·01) for the combined sodium hydroxide plus liquid supplement treatment. The calculated metabolizable energy intakes from straw were increased from 31 (nil) t o 36 by either the sodium hydroxide or liquid supplement treatments (P <0·05) and to 41 by the combined treatments (P <0·001). Sodium hydroxide tended to increase the concentrations of n- and iso-butyric acids in the rumen liquor.

Mutants of Bacillus subtilis can be developed to overproduce Val in vitro. It was hypothesized that addition of Bacillus subtilis mutants to pig diets can be a strategy to supply the animal with Val. The objective was to investigate the effect of Bacillus subtilis mutants on growth performance and blood amino acid (AA) concentrations when fed to piglets. Experiment 1 included 18 pigs (15.0±1.1 kg) fed one of three diets containing either 0.63 or 0.69 standardized ileal digestible (SID) Val : Lys, or 0.63 SID Val : Lys supplemented with a Bacillus subtilis mutant (mutant 1). Blood samples were obtained 0.5 h before feeding and at 1, 2, 3, 4, 5 and 6 h after feeding and analyzed for AAs. In Experiment 2, 80 piglets (9.1±1.1 kg) were fed one of four diets containing 0.63 or 0.67 SID Val : Lys, or 0.63 SID Val : Lys supplemented with another Bacillus subtilis mutant (mutant 2) or its parent wild type. Average daily feed intake, daily weight gain and feed conversion ratio were measured on days 7, 14 and 21. On day 17, blood samples were taken and analyzed for AAs. On days 24 to 26, six pigs from each dietary treatment were fitted with a permanent jugular vein catheter, and blood samples were taken for AA analysis 0.5 h before feeding and at 1, 2, 3, 4, 5 and 6 h after feeding. In experiment 1, Bacillus subtilis mutant 1 tended (P<0.10) to increase the plasma levels of Val at 2 and 3 h post-feeding, but this was not confirmed in Experiment 2. In Experiment 2, Bacillus subtilis mutant 2 and the wild type did not result in a growth performance different from the negative and positive controls. In conclusion, results obtained with the mutant strains of Bacillus subtilis were not better than results obtained with the wild-type strain, and for both strains, the results were not different than the negative control.

The objects of this investigation were to discover the amount of current inbreeding, the extent of any genetic divergence between the beef and dairy types, and whether the breed was dominated by an élite group of herds as for example, in the British Friesian (Robertson, 1953). An extensive investigation by Sewall Wright (1923a), (1923b) and McPhee and Wright (1925), (1926) established that there was at that time little current inbreeding and that genetic divergence between Dairy and Beef Shorthorns was negligible. This work adds to and corroborates their findings and throws some light on breed structure.

The sampling technique in this investigation is based upon Wright (1925). If consisted of noting the number, parents, grandparents and great-grandparents of a randomly selected sample of 128 females registered in Coates’ Herd Book, Vol. 94, 1948. Simple random lines were traced back from each great-grandparent as far as 1900, a toss of a coin deciding whether to record a sire or a dam. The information contained in Coates’ Herd Book made it a simple matter to record in addition the mate of the randomly selected ancestor, thus providing 16 random lines behind the eight great-grandparents.

Two groups of six male goats were used to assess the effects of rumen-protected supplements offish oil on intake, digestibility and nitrogen (N) balance. The animals were offered a diet consisting of forage and concentrate, the latter fraction supplemented with 0 (control) or lOOg/kg of rumen-protected fish oil supplement (PFO), containing a high proportion of the n-3 series (whole diet contained 0 or 60 g PFO per kg dry matter). No significant differences (P > 0.05) were found between the two groups concerning live-weight gain, food intake, digestibility of DM, organic matter, N, neutral-detergent fibre and energy. In contrast, there were differences (P < 0.05) regarding the digestibility of fat and of acid-detergent fibre, which were higher among the animals given the PFO diet. With respect to the individual fatty acids, we observed higher digestibility (P < 0.05) of C14:0, C16:0, C18:0 and C20:0 among the animals given the PFO diet. The digestibility of C14:0, C18:0 and C20:0 was found to be negative among the animals given the control diet. No significant differences (P > 0-05) were found regarding digestibility of total C18:1. In contrast, the coefficients for C18:2 (n-6) and C18:3 (n-3) were higher (P < 0.05) among the non-supplemented animals. The intake and faecal flow values of C18:0 suggest that the mono- and polyunsaturated fatty acids with 18 atoms of carbon may, in both cases, undergo partial hydrogenation, which would be greater among the control group. The utilization of C20:5 (n-3) and, especially, of C22 : 6 (n-3), which were consumed only by the animals given the PFO diet, was estimated at 1-000. The PFO diet also produced lower levels ofurinary-N excretion (P < 0.05), giving rise to higher N balances (P < 0.05).

An evaluation of the response to selection for prolificacy within a nucleus sheep flock of a commercial group-breeding scheme is presented. In 1979, the Romney Group Breeders formed a nucleus flock of 120 prolific ewes chosen from 12 contributing flocks. A control flock was established in 1982 from the same source. The analysis was conducted on the trait of litter size. Selection differentials are presented for each year of birth progeny group in both flocks. Expected selection response was calculated from selection differentials and was found to have an average value of 1·5% of parent mean litter size per year. Using least squares procedures the litter size performance of control and nucleus ewes of 2, 3 and 4 years of age was corrected for environmental effects. Realized response was estimated from the differences between corrected litter size means of control and nucleus flocks. Response in litter size was found to be significant within years and within ewe age groups (P < 0·05).

Twelve Friesian calves were each fitted with an abomasal cannula. The calves were placed in a controlled environment chamber and given a milk substitute diet in buckets at 12-h intervals. The calves were exposed to air temperatures of 25°C from 4 to 10 days of age, 5°C from 11 to 14 days of age, and 25°C at 15 days of age. At 9, 10, 11, 14 and 15 days of age, the abomasal contents of the calves were sampled at 2-h intervals and the temperature and pH of the abomasal contents were recorded at 40-min intervals for a period of 12 h. The rectal and abomasal temperatures of the calves were lower at 11 days of age than at 10 days of age, and were greater at 15 days of age than at 14 days of age (P < 0·05).

In a similar experiment four Friesian calves were each fitted with an ileal re-entrant cannula. The calves were exposed to air temperatures of 25°C from 5 to 19 days of age, 5°C from 20 to 26 days of age, and 25CC at 27 days of age. At 18, 19, 20, 26 and 27 days of age the ileal contents of the calves were collected and sampled for a period of 12 h.

No significant effects of the air temperatures of 25° and 5°C on the abomasal digestion (acidity and proteolytic activity of the abomasal contents) and ileal apparent digestibility of the diet were found.

The effects of nutrition on patterns of live-weight change, hair follicle activity, moult, hormone profiles and associated activities of monodeiodinase enzyme types II and III (MDII and MDIII) in cashmere goats were investigated. From 1 week before the winter solstice (mid December), one group of 15 animals was given a ration designed to provide 2·0 × live weight maintenance requirements (high; H) while a second, similar, group was given 0·8 × live weight maintenance requirements (low; L). After approximately 3 months, L animals had significantly lower mean live weights (P<0·01) than H animals. This was associated with lower (P<0·05) overall mean hair follicle activity in L than H animals during the March to May period and a lower overall mean moult score during March and April in L animals (P<0·01) but a similar mean date of moult onset. Mean concentrations of all of the hormones measured exhibited significant changes (P<0·01) with date of sampling. Overall mean concentrations of insulin, tri-iodothyronine and thyroxine did not differ with treatment but, compared with L animals, H animals exhibited higher mean concentrations of prolactin in April and May (P<0·05) and of insulin-like growth factor-1 in December and January (P<0·001). Rates of activity of MDII and MDIII in skin differed with date (P<0·001) but were not significantly affected by nutritional treatment. The MDIII/MDII ratio differed (P=0·05) with month but was significantly higher (P<0·05) in L than H animals in January, only. It is concluded that the reduction in hair follicle activity and the slower onset of moult associated with reduced nutrition were unlikely to be controlled, directly, by differences in activities of MDII or MDIII in skin tissue.

The influence of season and management system on the productivity of Friesian cows in a Mediterranean climate was assessed. Intakes of food and water and milk yields were measured in 154 cows over 2·5 years while intensively managed in yards giving access to shelter (free stalls) or that were fully exposed to solar radiation (open lots). Food quality was also monitored to permit estimates of the efficiency of utilization of metabolizable energy for milk production over fortnightly periods.

The highest milk yields and energetic efficiencies were recorded during spring. Energy intakes were highest but energetic efficiencies were lowest during winter. Cows consumed the least food during summer and autumn and drank the most water during summer. The only significant effect of management system was for water intake, which was higher in the open lots than in the free stalls. There was evidence of heat stress in summer and cold stress in winter, but there appeared to be little benefit with milk yields through the provision of shelter.

The delayed onset of heat-induced panting (at 42°C) immediately following previous shearing and exposure to cold was studied in 54 Scottish Blackface and 53 Tasmanian Merino sheep.

In control sheep (not previously cold-exposed) thermal panting commenced in 15 min. In cold-treated sheep, when the cold was intensified stepwise from +26°C (+30cC being thermoneutral) down to −10°C, using 2-hr exposures, or lengthened from 2 hr to 16 hr at +8°C, the delay (block) to panting increased non-linearly from 40 to 70 min.

The minimum intensity of cold required to produce a block (26°C in Merinos, 22°C in Blackfaces) was similar to that inducing peripheral vasoconstriction. More intense vasoconstriction preceded longer blocks, but vasoconstriction sometimes occurred without a subsequent block.

Merinos were more sensitive than Blackfaces to the blocking effects of cold, and, once blocked, the effect in Merinos was less easily removed by re-warming.

The time taken for cancellation of the heat debt during heat stress could account for half the block. The remainder, a delay of about 30 min, was attributed to a specific inhibition of respiratory control in the central nervous system.

Single nucleotide polymorphisms (SNPs) are the most widespread source of variation in genomes. While the very large number of SNPs allows for a very precise description of genetic variation, it impedes data processing and significantly increases analysis time. Many of the SNPs located close to each other frequently carry the same or similar information. This problem can be solved by selecting the most informative SNPs (tagSNPs) using linkage disequilibrium information by identifying a set of tagSNPs representative for a chromosome fragment. The goal of this study is to check whether the genetic structure of a population, expressed by relationship and inbreeding coefficients, affects tagSNP selection. Six subsets of 450 bulls are selected out of the 1228 Polish Holstein-Friesian bulls genotyped by the Illumina BovineSNP50 Bead Chip. TagSNPs are selected for each of the subsets, as well as for the whole data set. The average reduction of the SNP number is 77.2% and is very similar in each sub-population. Differences in tagSNP selection between sub-populations are small. On average, 93.88% of the tagSNPs overlap between subsets. The study showed that differences in the genetic structure of the reference population have little influence on tagSNP selection.

Ammonium bicarbonate is a solid, non toxic compound wich could be easily handled and applied to roughages as an alternative source of ammonia. The preliminary experiments reported here were designed to study the possibility of using ammonium bicarbonate for treating wheat straw.

In the first experiment samples of 100 g of wheat straw were placed in 28 glass jars (11 volume). The jars were then assigned in a factorial design to four levels of ammonium bicarbonate (0, 25, 50 and 75 g/kg on ammonia basis) and to seven temperatures of treatment (0, 20, 40, 60, 80, 100 and 120°C for 3 hours). After the treatment the straw samples were ground with a laboratory hammer mill (5 mm sieve). Two g of each sample were incubated in two replicated nylon bags (Ørskov, Hovell and Mould, 1980) into the rumen of two cannulated cows and withdrawn after 48 hours. The cows (mean live weight 550 kg) were fed 1.8 kg/100 kg live weight of a diet based on 0.80 hay, 0.15 dried sugar beet pulp and 0.05 soyabean meal, supplemented with vitamins and minerals.

This paper reports the second of two experiments which examined the possibility of improving pasture utilisation by restricting grazing and giving cows a supplement of concentrates. Two treatments (A and B) were continuously imposed, each on a group of 10 adult Ayrshire cows, for about 4 months. Cows received either pasture alone allocated daily by electric fence (B), or half this area of pasture plus 3 Ib. cubed concentrates per 10 lb. milk (A).

Herbage intakes were estimated by grass cutting techniques and also by faecal index methods, and animal performance was recorded. Over the whole experiment the two treatments gave similar levels of production per animal. Significant differences in milk yield and live-weight gain were detected only in periods 1 and 4, respectively, when the intended restriction was not completely achieved. While production per acre of grass was doubled by treatment a about 4,000 lb. grain was considered necessary to replace one acre of grazing.

The results are discussed in relation to the previous experiment. They suggest that the method of replacing half the normal grazing with barley or other concentrated feeds could be usefully employed to alleviate pasture shortage in parts of the grazing season and might therefore facilitate the maintenance of a high stocking rate.