This paper provides a practical interpretation of the arguments advanced at the meeting, summarized in the previous paper, on the protein requirements of the lactating cow. The evidence is by no means sufficiently detailed that all issues can be comprehensively resolved. Personal interpretation becomes necessary at some points. Far more important than this is the attention the meeting focused on the scope and ramifications of the problem, ranging from the nutrition of the rumen microflora to the fertility of the cow, such has hitherto not been achieved. This survey has been completed here by reference to several issues not dealt with extensively in the meeting.

In order to contribute to the genetic breeding programs of buffaloes, this study aimed to determine the influence of environmental effects on the stayability (ST) of dairy female Murrah buffalo in the herd. Data from 1016 buffaloes were used. ST was defined as the ability of the female to remain in the herd for 1, 2, 3, 4, 5 or 6 years after the first calving. Environmental effects were studied by survival analysis, adjusted to the fixed effects of farm, year and season of birth, class of first-lactation milk yield and age at first calving. The data were analyzed using the LIFEREG procedure of the SAS program that fits parametric models to failure time data (culling or ST = 0), and estimates parameters by maximum likelihood estimation. Breeding farm, year of birth and first-lactation milk yield significantly influenced (P < 0.0001) the ST to the specific ages (1 to 6 years after the first calving). Buffaloes that were older at first calving presented higher probabilities of being culled 1 year after the first calving, without any effect on culling at older ages. Buffaloes with a higher milk yield at first calving presented a lower culling probability and remained for a longer period of time in the herd. The effects of breeding farm, year of birth and first-lactation milk yield should be included in models used for the analysis of ST in buffaloes.

Lpin1 was a gene with important effects on controlling lipid/energy metabolism in humans and mice. However, little was known about chicken Lpin1 gene. In the present study, two transcript isoforms of chicken Lpin1 were identified. Lpin1-α was predicted encoding one 902 amino acid protein, whereas Lpin1-δ was predicted encoding one 918 amino acid protein with an insertion of 48-bp fragment from intron 12 of chicken Lpin1-α, and a conservative element was found to be located in intron 12 of chicken Lpin1-α genomic sequence. Ten variants were identified from chicken Lpin1-α coding sequence, and two missense mutations were predicted to affect the protein function of Lpin1. Reverse transcription PCR (RT-PCR) analysis revealed that chicken total Lpin1, Lpin1-α and Lpin1-δ were expressed in all analyzed tissues, and presented clear tissue expression differences. Real-time quantitative RT-PCR revealed that 30% energy restriction significantly elevated the total Lpin1 mRNA expression level in hepatic (P < 0.01) and adipose (P < 0.01) tissues of birds. Chicken total Lpin1 gene mRNA expression level presented a significantly inverse correlation with some traits including abdominal fat rate (P < 0.01), serum high-density lipoprotein (P < 0.05) and total cholesterol (P < 0.05), which would make a foundation for the further study on chicken Lpin1 gene function.

Wheat grain was given whole (W), cracked (C) or ammonia-treated (N) as the sole diet to six steers. In Expt 1, W, C and N were given at the rate of 2·1 kg per head per day. In Expt 2, W and N were given at the rate of 7·35 kg per head twice weekly; feeding of C had to be abandoned due to frequent bloat. Dry-matter digestibility was 0·79, 0·86 and 0·88 on W, C and N in Expt 1 and 0·75 and 0·83 on W and N in Expt 2.

The digestibility of neutral detergent fibre was 0·37, 0·24 and 0·57 with diets W, C and N respectively in Expt 1 and 0·27 and 0·47 with diets W and N in Expt 2.

The quantity of whole grain voided in faeces (g/kg grain fed) was 122, 3 and 31 with W, C and N in Expt 1 and 136 and 51 with W and N in Expt 2. Voided grains had a lower ratio of cr-glucose: neutral detergent fibre than grains fed, which indicated partial digestion of starch. Rates of nitrogen retention (g/day) were 6·6, 9·4 and 9·8 with W, C and N in Expt 1 and 7·2 and 12·2 with W and N in Expt 2.

It was concluded that ammonia-treated whole wheat grain is utilized as efficiently as cracked wheat grain when given as a sole diet to cattle and results in fewer digestive disturbances than cracked wheat grain.

Isovalerate supplements could stimulate rumen development by improving morphology and function of rumen mucosa, and then promote the growth of calves. This study was done to evaluate the effects of isovalerate supplements on morphology and functional gene expression of rumen mucosa in dairy calves. In total, 48 Chinese Holstein male calves with 15 days of age and 45.1±0.36 kg of BW were randomly assigned to four groups. The treatments were: control, low-isovalerate, moderate-isovalerate and high-isovalerate with 0, 3, 6 and 9 g isovalerate per calf per day, respectively. Supplementary isovalerate was hand-mixed into milk in pre-weaning calves and into concentrate portion in post-weaning calves. The study consisted of a 15-day-adaptation period and a 60-day-sampling period. Calves were weaned at 60 days of age. Three calves were slaughtered from each of the four treatments at 30, 60 and 90 days of age. The weight of body and stomach were measured, samples of ruminal tissues and blood were analyzed. Total stomach weight, total stomach to BW ratio, rumen wall and keratinized layer thickness, serum growth hormone and IGF-1 for both pre- and post-weaning calves increased linearly with increasing isovalerate supplements. Rumen to total stomach weight ratio, the length and width of rumen papillae, and serum β-hydroxybutyrate increased linearly for post-weaning calves. However, abomasum weight to total stomach weight ratio decreased linearly for both pre- and post-weaning calves. The relative messenger RNA expression for growth hormone receptor, IGF-1 receptor and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa increased linearly for post-weaning calves. Our results suggested that isovalerate supplements promoted rumen development in a dose-dependent manner. The optimum dose was 6.0 g isovalerate per calf per day.

Agroecology opens up new perspectives for the design of sustainable farming systems by using the stimulation of natural processes to reduce the inputs needed for production. In horse farming systems, the challenge is to maximize the proportion of forages in the diet, and to develop alternatives to synthetic chemical drugs for controlling gastrointestinal nematodes. Lactating saddle mares, with high nutritional requirements, are commonly supplemented with concentrates at pasture, although the influence of energy supplementation on voluntary intake, performance and immune response against parasites has not yet been quantified. In a 4-month study, 16 lactating mares experimentally infected with cyathostome larvae either received a daily supplement of barley (60% of energy requirements for lactation) or were non-supplemented. The mares were rotationally grazed on permanent pastures over three vegetation cycles. All the mares met their energy requirements and maintained their body condition score higher than 3. In both treatments, they produced foals with a satisfying growth rate (cycle 1: 1293 g/day; cycle 2: 1029 g/day; cycle 3: 559 g/day) and conformation (according to measurements of height at withers and cannon bone width at 11 months). Parasite egg excretion by mares increased in both groups during the grazing season (from 150 to 2011 epg), independently of whether they were supplemented or not. This suggests that energy supplementation did not improve mare ability to regulate parasite burden. Under unlimited herbage conditions, grass dry matter intake by supplemented mares remained stable around 22.6 g DM/kg LW per day (i.e. 13.5 kg DM/al per day), whereas non-supplemented mares increased voluntary intake from 22.6 to 28.0 g DM/kg LW per day (13.5 to 17.2 kg DM/al per day) between mid-June and the end of August. Hence total digestible dry matter intake and net energy intake did not significantly differ between supplemented and non-supplemented mares during the second and third cycles. In conclusion, supplementing lactating mares at pasture should not be systematic because their adaptive capacities enable to increase herbage intake and ensure foal growth. Further research is needed to determine the herbage allowance threshold below which supplementation is required.

Sixty pigs, equal numbers of boars and gilts of the two breeds Large White (LW) and Gloucester Old Spot (GOS), in litter groups of three, were divided equally between an initial slaughter group and two treatment groups; H, given a diet with 149 g/kg crude protein (CP) at a daily level of 0·1 W0·75; and L, given a diet with 193 g/kg CP at a daily level of 0·075 W0·75. The cumulative total amount of feed given to each pig was the same, 175 kg, but H received more energy per day. All pigs received the same CP per day but L received more CP in total. Pigs started on experiment at 12 weeks of age. The treatments differed mainly in their ability to promote fat deposition: H pigs grew faster than L, due mainly to a greater deposition of fat (as measured by the weight of subcutaneous fat produced) rather than lean (as measured by the weight of hind limb lean produced). H pigs had a poorer feed efficiency than L pigs.

The breeds were similar in most aspects of production and body composition over both treatments but GOS tended to be slower growing and fatter than LW, with shorter carcasses, thicker backfat, and smaller subcutaneous fat-free hind limbs. Boars were faster growing, leaner and more efficient than gilts, with a higher proportion of bone in the subcutaneous fat-free hind limb and a lower muscle: bone ratio (boars 4·74, gilts 5·28).

For several aspects of carcass composition the potential benefits of the lean types (LW and boars) over the fat types (GOS and gilts) were realized on treatment L but not on H. There was a significant breed × treatment interaction for lean content of hind limb: LW had higher values than GOS on L but both breeds were similar on H. Both LW and boars had significantly less subcutaneous fat than GOS and gilts respectively on treatment L but similar amounts on H.

Resting heat production (H), respiratory rate (RR) and rectal temperature (Tr) were measured at different controlled temperatures (Tt) in Hariana (Bos indicus) and its F, crosses with Jersey (JH), Brown Swiss (BH) and Holstein Friesian (FH) (Bos taurus) breeds and the values obtained were used to assess their relative thermosensitivity.

The lowest Tt at which H significantly decreased from that at 17°c was 32°c for Hariana, JH and BH and 27°c for FH after exposure for 8 days. The corresponding values after exposure for 18 days were 37°c for Hariana and 32°c for all the three crossbred groups. Differences between the genetic groups were also significant. The lowest Tt at which metabolizable energy (ME) decreased significantly in comparison with those at 17CC was 32°c in all the genetic groups. The differences in ME intake between genetic groups were significant only at 32°c Tt. The lowest Tt at which RR significantly increased from those at 17°c were 32°c in Hariana, 27°c in JH, BH and FH for both 5 to 7 and 15 to 17 days of exposure. The corresponding Tt for increase in Tr was 37°c in Hariana, 32°c in JH and 27°c in BH and FH at both 5 to 7 and 15 to 17 days of exposure.

The ambient temperature at which H would have significantly decreased and RR and Tr increased from the respective values at 17CC Tt were calculated curvilinearly for different genetic groups. There were differences in these values of calculated ambient temperatures between genetic groups and between exposure durations in respect of H, RR, and Tr, indicating differences in thermosensitivity.

The continuous presence of active male small ruminants prevents seasonal anestrus in females, but evidence of the same mechanism operating from the females to the males is scarce. This study assessed the effects of the continuous presence of ewes in estrus in spring on ram sexual activity, testicular size and echogenicity, and LH and testosterone concentrations. On 1 March, 20 rams were assigned to two groups (n = 10 each): isolated (ISO) from other sheep, or stimulated (STI) by 12 ewes, which were separated from the rams by an openwork metal barrier, allowing contact between sexes. Each week, four ewes were induced into estrus by intravaginal sponges. Live weight, scrotal circumference, testicular width (TW) and length (TL) were recorded at the beginning and at the end of the experiment, and testicular volume (TV) was calculated; at the same time, testicular ultrasonography and color Doppler scanning were performed. Blood samples (March to May) were collected once per week for testosterone determinations, and at the end of the experiment, blood samples were collected for 6 h at 20-min intervals for LH analysis. Rams were exposed to four estrous ewes in a serving-capacity test. Scrotal circumference, TW and TL were higher in the STI than in the ISO rams (P < 0.05) in May, and TV was higher (P < 0.05) in the STI (391 ± 17 cm3) than in the ISO rams (354 ± 24 cm3). In ISO rams, the number of white pixels was higher (P < 0.01) in May (348 ± 74) than in March (94 ± 21) and differed significantly (P < 0.01) from that of the STI rams in May (160 ± 33). In ISO rams, the number of grey pixels was higher (P < 0.05) in May (107 ± 3) than it was in March (99 ± 1). Stimulated and ISO rams did not differ significantly in mean LH plasma concentrations (0.8 ± 0.5 v. 0.9 ± 0.4 ng/ml), LH pulses (2.1 ± 0.5 v. 2.2 ± 0.2) and amplitude (2.0 ± 0.4 v. 3.2 ± 0.7 ng/ml, respectively). Stimulated rams had significantly higher testosterone concentrations than ISO rams from April to the end of the experiment. Stimulated rams performed more (P < 0.05) mountings with intromission (3.0 ± 0.4) than did ISO rams (1.5 ± 0.5). In conclusion, after 3 months in the continuous presence of ewes in estrus in spring, rams had higher TV and some testicular echogenic parameters were modified than isolated rams. Although exposed rams also had higher levels of testosterone after 2 months in the presence of estrous ewes, their LH pulsatility at the end of the study was not modified.

The aim was to determine the effect of orally administered ovine serum immunoglobulin (Ig) on growth performance, organ weight, gut morphology and mucin production in the Salmonella enteritidis – gavaged growing rat. Four groups consisted of non-gavaged rats fed a casein-based control basal diet (BD) and three groups of rats gavaged with 1 × 107 CFU S. enteritidis and fed a casein-based diet, a diet containing freeze-dried ovine Ig (FDOI) or a casein-based diet containing inactivated ovine Ig (IOI). The rats were randomly allocated to one of the four groups (n = 15/group) and received their respective diets for an 18-day experimental study. Gavaging took place on day 15. Average daily gain and body gain : feed ratio (post-gavage, 3 days) were significantly (P < 0.05) higher for the Salmonella-challenged rats fed the FDOI diet compared to those fed the BD and IOI diets. At the end of the study, the small intestine and colon were significantly (P < 0.05) heavier for the gavaged rats fed the FDOI diet compared to the gavaged rats fed either the BD or IOI diet. Moreover, the relative weights of the caecum, liver and spleen of the gavaged rats fed the BD or IOI diet were significantly (P < 0.05) heavier compared to the gavaged rats fed the FDOI diet. Generally, the gavaged rats fed the FDOI diet had significantly (P < 0.05) higher goblet cell counts and luminal mucin protein contents than the gavaged rats fed either the BD or IOI diet and had a more functional gut morphology. Overall, the FDOI fraction prevented the acute effects of S. enteritidis.

Sows housed with free access to water were found to have urine protein levels comparable to those recorded for man, dog and sheep. However, in stalled sows with restricted access to water, urine protein levels were twice as high as those of penned sows.

Physiological proteinuria has been found to occur in the piglet, in which respect it is similar to the ruminant and the dog. Proteinuria reaches a peak within 20 hr of birth and lasts for approximately 48 hr. The rapid decline in urine protein levels after this period coincides with gut closure. Proteinuria did not occur in piglets fed on glucose saline, only in those receiving colostrum; however, the continued feeding of colostrum did not prolong the period of proteinuria. In piglets fed varying levels of colostral protein there was a direct correlation between serum protein levels and mean urinary protein concentration during the period of proteinuria, but there was no direct correlation between the amounts of colostral protein ingested and the serum protein level.

Concentrations of growth hormone (GH), insulin-like growth factor (IGF-1), insulin and glucagon were determined in the plasma of growing bulls, steers and heifers (no. = 138 in total, German Simmental breed). The animals were offered either a high level or a low level of energy resulting in relatively high and low average daily gain. Trials were subdivided into two experimental series and started at approximately 3 months of age at an average live weight of 110 kg. The animals were slaughtered at different body weights from 200 to 510 kg (heifers) or 660 kg (bulls, steers). Blood samples (needle puncture) were collected at biweekly intervals. Frequent samples time-course analysis of GH were taken by catheter from nine animals in total. Concentrations of GH declined during growth in steers and heifers as well as in bulls in blood samples collected by means of a catheter. IGF-1 and insulin concentrations increased from the start of the trial onwards up to different ages among the groups. Concentrations of glucagon constantly decreased from the start of the trial until slaughter. Significant differences (P < 0·05) in concentrations ofGH, IGF-1 and insulin could be observed between sexes and levels of nutrition, with the highest GH and IGF-1 levels in bulls followed by steers and heifers. In contrast insulin values were highest in heifers followed by steers and bulls. A high level of nutrition increased concentrations of IGF-1 and insulin in all sexes.

Azaperone treatment can control aggression and decrease stress due to weaning, re-grouping and hierarchical fighting of gilts and sows. However, the effects of this butyrophenone neuroleptic and sedative administered at weaning on pig reproductive function are poorly characterized. In this year-long study, a total of 619 cross-bred sows (Polish Large White×Polish Landrace) kept on a commercial farm received an i.m. injection of azaperone (Stresnil®; 2 mg/kg BW) just before weaning and were artificially inseminated during the ensuing estrus with 3×109 spermatozoa per dose of an inseminate; 1180 sows served as untreated controls. Immediately after weaning, the sows were moved to four pens of seven to nine animals each. A teaser boar was used twice daily to check for estrus and sows were bred at heat detection. Subsequently, all sows stayed in individual stalls until pregnancy testing on day 30 post-artificial insemination and were then re-grouped until farrowing. The proportion of pigs that were in estrus within 6 days post-weaning was significantly lower in azaperone-treated groups of animals than in controls (71.4% v. 84.2%). Overall, the azaperone-treated sows had a significantly longer weaning-to-estrus interval (WEI; 8.7±10.1 v. 6.3±8.1 days; mean±SD) and a significantly larger litter size (LS: 11.8±3.0 v.11.3±3.2; azaperone-treated v. control sows). Treatment of the winter-farrowing sows was associated with increased LS (12.8±2.6 and 11.3±3.1 piglets/sow, respectively; P<0.05) and longer (P<0.05) weaning-to-effective-service intervals (11.7±19.3 and 8.4±12.3 days, respectively) as well as farrowing intervals (155.7±19.7 and 152.2±16.1 days, respectively) compared with untreated controls. In the summer months, significantly longer WEIs (12.1±21.0 v. 8.4±16.9 days) were accompanied by a significant decline in LS only in azaperone-treated sows that were inseminated within 6 days post-weaning (10.8±2.9 v. 11.5±3.3 piglets/sow; azaperone-treated v. controls). Azaperone-treated second parity sows had greater LS (P<0.001) along with prolonged WEIs (P<0.05) in comparison to their respective controls, regardless of the timing of estrus. An application of azaperone at weaning increased the annual piglet productivity of winter-farrowing animals and of second parity sows but depressed it significantly in summer. The extra cost and labor due to delayed onset of estrus may cancel out any reproductive benefits of azaperone treatment.

Three steers cannulated in the rumen and abomasum were given a diet of wheat straw, chopped and soaked in sodium hydroxide and then washed to pH less than 8. The straw was sprayed with sucrose, urea and minerals. The diet was free of digestible protein and given at 1·7 to 4·1 kg/day. Microbial protein flowing to the omasum was measured by 15N. By difference, the flow of endogenous protein nitrogen to the omasum was found to be 2·2 g/kg dry-matter intake. The flow of endogenous protein nitrogen to the abomasum was 3·3 to 9·4 g/kg dry-matter intake, and it decreased with increasing food intake.

The objective of this study was to evaluate genetic and non-genetic factors influencing artificial insemination (AI) success in French dairy goats. Data analysis, on a total of 584 676 and 386 517 AI records for Alpine and Saanen breed, respectively, collected from 1992 to 2009, was conducted separately on each breed. We used a linear simple repeatability animal model which combined male and female random effect and environmental fixed effects. The most important environmental factor identified was the period within year effect due to the European heat wave of 2003. The estimated values of the annual fertility exhibited a negative trend of 1% loss of AI success per 10 years for Alpine breed only. The range of variation for the flock×within years random effect was 70% and 65% for Alpine and Saanen breeds. The negative effect on AI success of antibody production after repetitive hormonal treatment was confirmed. We observed an important positive relationship between fertility and protein yield expressed as quartile within flock×years of protein 250-day yield for female with lactation number over 1, while this trend was negative for primiparous females. We detected a negative effect of the duration of conservation of semen with a difference of about 4% of AI success between extreme values (2 to 8+ or 9+ years). Heritability estimates for male fertility were 0.0037 and 0.0043 for Alpine and Saanen breed respectively, while estimates for female fertility was 0.040 and 0.049. Repeatability estimates for males were 0.008 and 0.010 for Alpine and Saanen, respectively, and 0.097 and 0.102 for females. With such low values of heritability, selection can hardly affect fertility.

The half carcasses of 39 pre- and postnatal Romney sheep were dissected into anatomical units of bone and, where possible, into 32 muscle units which comprised nine functional groups. The growth of wet weight of the total bone and of the muscle groups (and their chemical components, which included deoxyribonucleic acid, protein, and total lipid) was compared with the growth of the carcass using allometric analysis.

Although bone grew faster prenatally than postnatally relative to carcass weight, the growth of total muscle and of all the muscle groups and their chemical components occurred at a constant, linear rate throughout the growth period studied.

The muscle: bone ratio decreased during prenatal growth, reached a minimum at around parturition and then increased postnatally.

The abdominal, m. longissimus and thigh muscle groups grew faster than total side muscle, relative to carcass weight.

Protein, and especially triglyceride, grew at relative rates which exceeded that of muscle wet weight.

The amount and proportion of intramuscular triglyceride, and the weights of the muscle groups in sheep at three different stages of growth, were predicted from allometric equations. The content of triglyceride was greatest in the cutaneous and neck muscle groups. As a proportion of total muscle, the thigh, m. longissimus and abdominal groups increased as carcass weight increased from 1 kg to 15 kg.

Two experiments were carried out to compare three methods of harvesting grass silage for beef production. These involved (a) harvesting the grass directly with a flail forage harvester (b) pre-cutting the grass with a rotary mower and harvesting it with a precision-chop forage harvester without wilting and (c) pre-mowing and harvesting with a precision-chop forage harvester after field wilting for 36 to 80 h (experiment 1) or 20 to 24 h (experiment 2). Half of the grass harvested by each method received formic acid at a rate of 2·5 1/t while the other half received no additive. The silages were offered ad libitum and supplemented with 2·6 kg concentrates per head daily to 72 castrated male cattle in each experiment. The unwilted and wilted herbages had mean dry-matter concentrations of 163 and 273 g/kg at ensiling and all silages were well preserved. Harvesting silage with a precision-chop rather than a flail forage harvester produced only a small non-significant increase in intake (0·034) and performance (0·046) and did not affect carcass gain per ha. Field wilting for 36 to 80 h prior to ensiling (experiment 1) reduced animal performance by 0·08 and beef output per ha by 0·11. Wilting for 20 to 24 h in ideal weather (experiment 2) did not affect animal performance or beef output per ha compared with that produced by well-preserved, unwilted silage. There was no significant interaction between method of harvesting and additive treatment.

An F2 cross between Duroc and Large White pigs was carried out in order to detect quantitative trait loci (QTL) for 11 meat quality traits (L*, a* and b* Minolta coordinates and water-holding capacity (WHC) of two ham muscles, ultimate pH of two ham and one loin muscles), 13 production traits (birth weight, average daily gain during post-weaning and fattening periods, carcass fat depths at three locations, estimated lean meat content, carcass length and weights of five carcass cuts) and three stress hormone-level traits (cortisol, adrenaline and noradrenaline). Animals from the three generations of the experimental design (including 456 F2 pigs) were genotyped for 91 microsatellite markers covering all the autosomes. A total of 56 QTL were detected: 49 reached the chromosome-wide level (suggestive QTL with a maximal probability of 0.05) and seven were significant at the genome-wide level (with a probability varying from 6 × 10−4 to 3 × 10−3). Twenty suggestive QTL were identified for ultimate pH, colour measurements and WHC on chromosome (SSC) 5, 6, 7, 8, 9, 11, 13, 14, 15 and 17. For production traits, 33 QTL were detected on all autosomes except SSC6, 8 and 9. Seven of these QTL, located on SSC2, 3, 10, 13, 16 and 17, exceeded the genome-wide significance threshold. Finally, three QTL were identified for levels of stress hormones: a QTL for cortisol level on SSC7 in the cortisol-binding globulin gene region, a QTL for adrenaline level on SSC10 and a QTL for noradrenaline level on SSC13. Among all the detected QTL, seven are described for the first time: a QTL for ultimate pH measurement on SSC5, two QTL affecting birth weight on SSC2 and 10, two QTL for growth rate on SSC15 (during fattening) and 17 (during post-weaning) and two QTL affecting the adrenaline and noradrenaline levels. For each QTL, only one to five of the six F1 sires were found to be heterozygous. It means that all QTL are segregating in at least one of the founder populations used in this study. These results suggest that both meat quality and production traits can be improved in purebred Duroc and Large White pigs through marker-assisted selection. It is of particular interest for meat quality traits, which are difficult to include in classical selection programmes.

An implantation technique utilizing slow-release selenium pellets was evaluated as a means of controlling nutritional muscular dystrophy (NMD) in sheep. Sixty ewes were fed a dystrophy-producing hay and implantations were made at mid-pregnancy (14 animals) and in late pregnancy (15 animals); the remainder were kept as controls. Selenium was determined at intervals on milk and blood samples from the ewes and on blood samples from the lambs. Various muscles were examined histologically for NMD lesions.

Selenium levels in the milk of implanted ewes were higher than controls up to the 60th day of lactation and levels in the blood of both ewes and lambs were higher than controls during nursing. Selenium implantation at mid-pregnancy resulted in higher selenium concentrations in lamb's blood at birth than implantation in late pregnancy. However, by 30 days of age and thereafter, this difference was reversed. Large variability was encountered in the blood values for implanted ewes and their lambs. While complete protection against NMD was not achieved, implantation reduced the incidence and severity of the disease. The earlier implantation gave slightly fewer deaths from NMD, but the numbers were too small to make critical comparisons.

Data on 1,795 Scottish Blackface sheep were examined to see what effect treatment during the animal's first winter had on subsequent performance. Two treatments were used, wintering on the hill with the breeding ewe flock, or wintering away on low-ground farms. Away-wintered sheep gained on average about 16 lb. more than hill-wintered sheep between 6 and 12 months of age. These live-weight differences declined with age to about ⅔lb. at 5–6 years of age. Away-wintered sheep also had heavier first fleeces by about fIb. on average and had a lower mortality rate. However, differences in subsequent fleece weights and lamb production were small and not sufficient to cover the cost of away wintering.