bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of semen volume and number of spermatozoa on the fertility of intra-uterine inseminations of pigs
Authors: Hancock J. L. , Hovell G. J. R.
Published: September 2010

Forty-eight sows were inseminated into the uterus with semen (sperm fraction) diluted to 20 ml. with an egg-yolk glucose phosphate (YPG) diluent to contain 10·0 × 109, 1·0 × 109 and 0·1 × 109 spermatozoa. In 24 sows (120 ml. group) insemination of the 20 ml. diluted semen was followed by the intra-uterine insemination of 100 ml. YPG diluent, alone. The success of insemination was judged at autopsy from ova recovered 2-4 days after insemination (Experiment A) or from counts of foetuses present 25 days after insemination (Experiments B and C). In Experiment A the numbers of ‘cleaved’ ova were recorded before fixation: the numbers of ova judged to be ‘fertilised’ were counted in preparations of fixed and stained ova. For 24 sows inseminated with 20 ml. semen alone at the three dosage levels (10·0 × 109, 1·0 × 109 and 0·1 × 109 spermatozoa) the percentages of ‘cleaved’ and ‘fertilised’ ova were 78·5 and 80·9; 83·5 and 81·2; 24·6 and 19·8. For sows inseminated with the same sperm numbers in 20 ml. semen followed by 100 ml. diluent, the percentages were 41·5 and 43·9; 44·2 and 36·2; 24·6 and 6·7. Comparison of numbers of sows with some ova cleaved (or ‘fertilised’) and sows with none cleaved (or ‘fertilised’) showed no significant differences in sow fertility between treatments.

Comparison of numbers of sows with all ova cleaved (or ‘fertilised’) and sows with none cleaved (or ‘fertilised’) shows that inseminations with the 20 ml. volume, alone, were of significantly higher fertility than those inseminated with 120 ml.

Estimates of fertility based on the examination of unfixed ova differed in 9 sows from estimates based on the examination of fixed and stained ova. In one sow some uncleaved ova were shown to be pronucleate after fixation and staining. Morphologically abnormal ova were identified in 6 sows; most of these abnormal ova showed multinucleate blastomeres. These abnormal ova were found only in sows inseminated with not more than 1·0 × 109 spermatozoa.

Counts of the numbers of spermatozoa on fixed ova showed that these tended to decline as the number of spermatozoa inseminated declined. Comparing sows inseminated with the same number of spermatozoa there tended to be fewer spermatozoa on ova from sows inseminated with 120 ml. than on ova from sows inseminated with 20 ml.

Of 13 sows in Experiment B inseminated with 20 ml. semen containing 10·0 × 109 spermatozoa, 9 had foetuses present at autopsy 25 days later (11·6 foetuses per sow).

Of 17 sows in Experiment C inseminated with 20 ml. semen containing 1·0 × 109 spermatozoa, 7 had foetuses present at autopsy 25 days later (7·1 foetuses per sow).

The difference in pregnancy rate for the two groups is not statistically significant.

Differences in litter size between the two groups of sows are explainable by differences in ovulation rate between the two groups (group B, 18·2 corpora lutea per sow, group C, 13·4 corpora lutea per sow).
Weight changes in sows during pregnancy and lactation
Authors: Lodge G. A. , McDonald I. , MacPherson R. M.
Published: September 2010

Results are presented on weight changes in sows which indicate (1) that checks to increases in weight at specific stages appear to be a normal function of pregnancy in sows, (2) that most of the weight gained during pregnancy in excess of that accounted for by the litter and placenta is lost before the next pregnancy, either during lactation or, if this is prevented, immediately after weaning, (3) that considerable weight loss occurs between weaning and re-mating on a level of feeding which is sufficient to allow a mean gain of 1 lb. per day during pregnancy, and (4) that sows given a relatively low level of total feed during lactation appear to lose considerably less weight between weaning and re-mating, and to gain weight more rapidly during the first few weeks of pregnancy, than those fed to a relatively high level during lactation. Practical implications of these results are considered.
The causes of differences in production between dairy herds
Authors: Brumby P. J.
Published: September 2010

The extent of the genetic differences existing among a sample of the dairy herds of New Zealand was assessed by a direct experimental approach. In part one of the experiment, 240 young calves were taken from 40 herds of markedly different production levels and reared and milked as a uniformly treated herd of cattle at Ruakura. In part two of the experiment 120 sets of identical twin calves were divided amongst these 40 high- and low-producing herds.

Results indicated that in general there were no obvious genetic differences between the cattle in the high and low herds in body size, fertility, milk production or days in lactation. There were, however, genetic differences between the high and low herds in milk composition; approximately 50% of the differences between herds in butterfat and protein content and 25% of the SNF content were due to genetic differences between herds.

Genetic differences between herds in yield were found within the high group of herds but not in the low.

Evidence was obtained indicating that interactions between herd environment and the genotype of individual animals provided an appreciable source of variation.

The production level of a herd in which an animal was reared was without effect upon its subsequent production potential for milk yield.
Compensatory growth and sexual maturity in mice
Authors: Monteiro L. S. , Falconer D. S.
Published: September 2010

The effects of environmental factors in the pre-weaning period on the subsequent growth of mice were studied. The variance caused by maternal effects, i.e. by environmental factors common to litter-mates, increased from birth to 4 weeks of age (1 week after weaning) and then decreased by about 60% between 4 and 8 weeks. Furthermore, a high litter weight at 4 weeks was followed by low subsequent growth and vice versa. The occurrence of compensatory growth from 4 weeks onwards was thus established. In contrast, the genetically determined variation of body weight did not show any reduction during the period of compensation, but increased up to 8 weeks of age.

The modification of the growth curve, by which compensation was achieved, was then studied. It was found that the inflexion point separating the initial phase of exponential growth from the subsequent phase of asymptotic growth corresponded closely with the attainment of sexual maturity in females, as judged by the opening of the vagina. Sexual maturity was reached at approximately the same weight in all litters, but at widely different ages. Thus, litters with rapid early growth as a result of a good maternal environment reached sexual maturity and consequently entered the asymptotic phase early, while litters with slow early growth entered the asymptotic phase late. Compensatory growth was therefore achieved through curtailment or prolongation of the exponential phase of growth.
Ground roughage in the diet of the early-weaned calf
Authors: Leibholz Jane
Published: September 2010

An experiment was conducted with 60 male Friesian calves between 5 and 11 weeks of age. The experiment was a 5×2×2 factorial design. The five major treatments were the inclusion of 20 or 40% ground wheat straw or 20, 40 or 60% ground lucerne in a pelleted diet. A methane inhibitor was included in the diet given to 30 of the calves. The diets were given alone or with a chaffed wheat straw supplementad libitum. All diets contained 2% sodium bicarbonate.

The weight gain of the calves was greater with the diets containing ground lucerne than with those containing ground wheat straw, but in both cases weight gains were reduced with increasing roughage content of the diets. The efficiency of feed conversion showed a similar trend. The supplementation of the diets with chaffed wheat straw did not affect the performance of the calves. The inclusion of the methane inhibitor in the diets improved the weight gains and efficiency of feed conversion. The daily retention of nitrogen in the calves showed a similar trend to the growth rates.

The molar percentage of acetate in the rumen increased as the roughage content of the diets increased while the proportions of propionate, butyrate and valerate decreased. The inclusion of the methane inhibitor in the diets decreased the concentration of total volatile fatty acids (VFA) in the rumen and increased the molar percentage of propionate, butyrate and valerate.
Effect of diurnal air temperature cycles on growth and food conversion in pigs
Authors: Morrison S. R. , Heitman H. , Givens R. L.
Published: September 2010

In trials with 64 pigs growing from 37 to 60 kg or from 65 to 88 kg growth rate and food conversion were not affected by either a 10°C or a 20°C range in diurnal air temperature cycle compared with a constant temperature equal to the mean of the cycle when the mean temperatures were optimal. However, with a constant temperature and cycle mean at 6°C above optimum, performance declined with a 20°C range cycle.
The influence of pellet size and density on the intake by calves of dried grass pellets given as supplements to hay
Authors: Tetlow R. M. , Wilkins R. J.
Published: September 2010

High (1·31 kg/1) or medium-density (1·17 kg/1) dried grass pellets of 9, 12 or 18 mm diameter were given to British Friesian male calves of 7 to 14 weeks of age as supplements to chopped hay (Experiment 1). Pellets were given ad libitum but with access limited to two periods of 1½ h per day, and hay was given ad libitum for the remaining 21 h. In Experiment 2, high (1·34 kg/1) or medium-density (1·14 kg/1) dried grass pellets of 18 mm diameter were given to British Friesian male calves of 26 to 30 weeks of age. Pellets were given as supplements to chopped hay as in Experiment 1.

There was no effect of pellet size or density on total intake of organic matter or live-weight gain by calves in either experiment. With the exception of animals given pellets of 12 mm diameter in Experiment 1, animals in both experiments consumed less pellets of high density than of medium density, but they were able to compensate for low pellet intake by eating more hay.

The coefficients of variation for intake were higher in Experiment 1 than in Experiment 2, and higher for the intake of pellets than for total intake. There was a progressive increase in the intake (g organic matter/kg M0·75 per day) by calves in Experiment 1, whereas in Experiment 2 intake increased for the first 10 days and then remained constant. On average the proportion of pellets and hay consumed did not change in Experiment 1, but in Experiment 2 the proportion of pellets in the feed consumed increased from 53·5 to 60·6%.
Digestibility of whole barley and oat grains by cattle of different ages
Authors: Morgan C. A. , Campling R. C.
Published: September 2010

1. Three trials were conducted to investigate in cattle of different ages the digestibility of whole barley and whole oat grains in diets with approximately a 1:1 ratio of hay to concentrates. The cattle used were four 17-month-old steers in Trial 1; four non-lactating cows in Trial 2; and six heifers at 7, 10, 13 and 16 months of age in Trial 3. 2. Steers and cows completely digested the starch in the rolled cereals and the steers digested more of the starch of whole barley than the cows. The digestibility of starch in whole oats was high (0·72) and similar in both types of cattle.

3. The heifers when 7 months of age had the highest coefficients of starch digestibility for both whole barley and whole oats (0·62 and 0·83 respectively). Digestibility of starch declined with age, but this effect was masked by variations within and between animals at different ages. It is concluded that barley should be rolled before feeding but with oats the benefits from rolling are likely to be small and possibly only worth while when given to adult cattle.
Effect of high-protein supplements on the utilization of body reserves by single-suckling cows
Authors: Chestnutt D. M. B.
Published: September 2010

In three successive experiments 32, 30 and 32 autumn-calving, single-suckled cows were subjected to individual planned weight reductions over winter on silage-based diets with various levels of concentrate supplement. At a similar level of weight loss, milk yield and calf gain were increased when protein supplements of low rumen degradability were given. On average, the inclusion of 0·75 kg fish meal in the diet improved calf gain by 0·13 kg/day. Results are discussed in terms of the effect of protein supplement on the efficiency of use of body reserves.
In vitrogas and foam production by rumen fluid from cows of genetically high or low susceptibility to pasture bloat
Authors: Cockrem F. R. M. , McIntosh J. T. , McLaren R. D. , Morris C. A.
Published: September 2010

Rumen fluid was obtained from rumen fistulated cows (two of high (HS) and two of low (LS) susceptibility to bloat) which were bred in experimental herds subjected to long-term divergent genetic selection for pasture bloat susceptibility. In vitro fermentation using strained rumen fluid from each cow with various pasture juice substrates showed no differences between HS and LS in gas production per unit of rumen fluid or in foam production per unit of gas production. Fluid from cows on grazed pasture produced greatest gas volumes. Clover juices produced more foam of similar stability to ryegrass and mixed pasture juices. Foam production per unit of gas was greater for all juices when the rumen fluid was from cows grazing bloat potent pasture.
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight 4. Partitioning of dissected and chemical fat in the body
Authors: Thompson J. M. , Butterfield R. M. , Perry Diana
Published: September 2010

Changes in the partitioning of both dissected and chemical fat were examined from birth to maturity, in rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. The partitioning of fat between six dissected and 11 chemical fat partitions in the body was examined in 34 mature animals, and the maturing patterns for these fat partitions calculated relative to the weight of total body fat, using the mean values for the mature animals and individual data from 106 immature animals.

Strain had no effect on the partitioning of dissected fat in the mature animals, but did affect the partitioning of chemical fat in the bone and pelt partitions. Mature ewes had greater proportions of dissected subcutaneous and kidney fat, and lower proportions of dissected intermuscular and scrotal/udder fat, than the mature rams.

There were significant strain and sex effects on maturing patterns for dissected subcutaneous and intermuscular fat. Strain and sex effects were also significant for the maturing patterns of some chemical fat partitions.

Selection for high or low weaning weight had little effect on the partitioning of either dissected or chemical fat when compared at the same stage of maturity of total fat. There were large differences in the partitioning of both chemical and dissected fat between the rams and the ewes when compared at either the same weight of total fat, or the same stage of maturity of total fat in the body.
The digestible and metabolizable energy of two fat blends for growing pigs as influenced by level of inclusion
Authors: Wiseman J. , Cole D. J. A.
Published: September 2010

Two fat blends differing in free fatty acid concentration and fatty acid composition were included in cereal-based diets at concentrations of 10, 30, 50, 70, 90 and 110g/kg. The digestible (DE) and metabolizable (ME) energy of each diet were estimated in a metabolism experiment based on three 4 × 4 Latin squares using gilts of 30 kg initial live weight fitted with indwelling bladder catheters. With increasing dietary fat both DE and ME increased linearly (P < 0·001) and the linear equations derived were used to calculate the DE values of the two fats by extrapolation. Values were 26·4 and 24·2 MJ/kg respectively for fats A and B. The change in dietary D E and ME to increasing dietary fat concentration showed a curvilinear trend (P = 0·0987 and 0·1268 respectively for DE and ME ) indicating that fats may not be correctly evaluated at only one rate of inclusion. The quadratic functions derived were interpolated to provide DE and ME data for the two fats. Values for DE for fat A ranged from 32·7 o t 25·7 MJ/kg at 10 and HOg/kg, and for fat B from 38·6 to 26·3 MJ/kg at 10 and 110 g/kg. Data for ME followed similar trends. It was concluded that multi-level assays are important in the evaluation of fats and that the rate of decline of fat DE and ME was specific to the fat examined.
The effect of diet in winter on the body composition of young steers and subsequent performance during the grazing season
Authors: Baker R. D. , Young N. E. , Laws J. A.
Published: September 2010

Friesian steer calves born in August were reared from 3 to 7 months of age on silage alone (S) or on silage and concentrates to supply metabolizable energy (ME) in the proportion of 0·5: 0·5 (55) or 0·1: 0·9 (19). The mixed diets were either offered to appetite (55A and 19A) or restricted to provide the same energy intake as the S group (55R and 19R). The cattle were then grazed for a 6-month period as a single group. During the winter the S, 55R and 19R groups had similar live-weight gains. Despite having the highest nitrogen intakes the S group deposited less protein, but more fat than the other two groups. There were no significant differences within A or R groups, but the A groups had higher live weights, empty-body weights and carcass weights than the R groups and had more fat and less protein per kg empty body weight at turn-out to grazing.

Compensatory growth was exhibited by the S, 55R and 19R groups during the grazing season. It arose because of differences in intake and not because of differences in the energy content of the gain. Intake was inversely related to the level of fat per kg empty body weight at the start of grazing. There was no evidence that the nature of the diet in winter had an effect on subsequent herbage intake.

It was concluded that diet per se in winter had no residual effect on intake at grazing, but that it did have direct and residual effects on the relative deposition of fat and protein which could lead to an association between the level of fat in the empty body and intake. Inefficient use of nitrogen from silages with moderate fermentation characteristics was also demonstrated.
Total amino acid requirements of weaned piglets 8 to 25 kg live weight given diets based on wheat and soya-bean meal fortified with free amino acids
Authors: Gatel F. , Buron G. , Fékéte J.
Published: September 2010

Two experiments were carried out with weaned piglets from 8 to 25 kg live weight in order to determine the dietary amino acid content necessary for maximum growth. Six diets based on wheat, soya-bean meal, soya-bean oil and free amino acids were compared in each experiment. Essential amino acids were in the same relative proportion for all diets: (methionine + cystine)/lysine = 0·60 to 0·65; threonine/lysine = 0·65; tryptophan/lysine = 0·19. The range of amino acid content was 9·53 to 12·52 g lysine per kg in the first experiment and 11·34 to 15·94 g lysine per kg in the second experiment. The number of piglets used per diet was 136 (20 pens) and 106 (16 pens) in respectively the first and the second experiment. The relationship between either dietary lysine content or daily lysine intake and growth rate was quadratic and significant. Dietary lysine content and daily lysine intake which enable maximum growth were calculated according to this model. Dietary lysine contents were 15·5 and 14·9 g/kg for the first 3 weeks (8 to 17 kg) and for the overall post-weaning period (8 to 25 kg) respectively. Daily lysine intakes were 10·6 and 13·3 g/day respectively for the same two periods. Reasons for these values being higher than those currently cited are discussed.
Measuring hunger in the pig using operant conditioning: The effect of food restriction
Authors: Lawrence A. B. , Appleby M. C. , Macleod H. A.
Published: September 2010

Operant conditioning techniques were used to measure the feeding motivation (hunger) of pigs restricted to the low food levels used under certain commercial conditions. Six Large White × Landrace boars were maintained in individual pens where they received their daily food allowance. Initially food was available ad libitum; subsequently boars were restricted proportionately to 0·8, 0·6 and 0·4 of their ad libitum intake in a Latin-square design. Finally boars were again offered their previously measured ad libitum intake (treatment 1·0). Hunger was measured by conditioning boars to press a panel 10 times to receive a 7-g reward of food. Operant response rates were measured over 20-min sessions during each of the treatments and at three times of day (pre-feeding, immediately post feeding and 5 h post feeding).

Operant response rate was strongly affected by restricting food allowance (means: treatment 1·0, 42 panel presses; 0·8, 212; 0·6, 266; 0·4, 320). There was a signficant interaction between food allowance and time of day (P < 0·001). Treatments did not vary in response rate before feeding. Treatments 1·0 and 0·8 depressed response rate post feeding (P < 0·001) and treatment 1·0 also 5 h post feeding (P < 0·001). Response rates on treatments 0·6 and 0·4 did not vary significantly from one another or with time of day.

Restricting pigs to low food levels resulted in a high level of hunger throughout the day. This was so even for food allowances that met current recommended feeding levels sufficient for maintenance and low weight gain (treatment 0·6 equivalent to 1·3 times maintenance). Commercial levels of feeding for the pig breeding population whilst meeting production needs do not satisfy feeding motivation. The hunger resulting from low food levels may act as a major source of stress under certain husbandry conditions such as tether and stall systems for dry sows, where sows are subject to both physical and food restriction.
A note on the breeding season of Lincoln ewes at Bahia Blanca, Argentina
Authors: Iglesias R. M. Rodriguez , Giglioli C. , Irazoqui H.
Published: September 2010

Days elapsed from the mid point of the anoestrous period to first (DF) and last (DL) oestrus of the breeding season and duration of this breeding season (DD) within a flock of 60 adult Lincoln ewes are reported in this note. All traits showed considerable variation and the phenotypic correlation between DF and DD was −0·57 (P < 0·01) while that between DL and DD was 0·87 (P < 0·01). However, DF was not correlated with DL (P = 0·10).
The effects of protein and energy content of compound supplements offered at low levels to October-calving dairy cows given grass silage ad libitum
Authors: Davies O. D.
Published: September 2010

Ninety-six October calving, multiparous Friesian dairy cows were given from week 2 of lactation perennial ryegrass silage ad libitum, supplemented with one of four compound foods, offered at a flat rate of 3 kg/day. The compound foods differed in crude protein (CP) concentration (210 (LP) and 350 (HP) g/kg dry matter (DM)), achieved by including fish meal at 50 and 250 kg/t respectively; and in metabolizable energy (ME) concentration (12·8 (LE) and 14·0 (HE) M/kg DM), achieved by adding protected fat (approx. 100 kg/t). There were no significant interactions between supplement type in terms of animal performance. Over an average feeding period of 152 days, milk yields were significantly increased by 0·49 kg/day per 100 g supplementary CP (P < 0·01) and 0·50 kg/day per MJ of supplementary ME (P < 0·05).

Increasing the level of supplementary CP had no effect on milk composition but significantly increased yield of milk protein (67 g/day). An increase in supplementary ME significantly reduced protein concentration in the milk (1·1 gjkg) but had no effect on protein yield. Yield of milk fat was significantly increased (76 g/day). The additional energy also significantly improved cow fertility in terms of a reduced interval from calving to both first service and conception.
A note on haemoglobin levels in West African cattle
Authors: Wharton F. D.
Published: September 2010

The physiology of indigenous West African cattle has not been investigated thoroughly. The ability of native cattle to survive on dietary regimes drastically deficient by standards based on requirements of temperate zone cattle, indicates an adaptability suggestive of a physiology differing from that of temperate zone cattle. The study reported herein was conducted to provide information on one aspect of this problem; namely the haemoglobin levels of indigenous cattle, as influenced by breed, season of year, growth characteristics and nutrient intake.
Social behaviour of domestic animals II. Effect of the peck order on poultry productivity
Authors: McBride G.
Published: September 2010

1. Peck order position was assessed by aggressiveness scores for birds housed intensively on deep litter on the floor and in cages.

2. Relationships were shown between scores and egg weight, egg number and egg mass for the birds on the floor but not for the caged birds. The nature of the relationships found was discussed.

3. The correlation between egg weight and egg number was higher in the flock on the floor than in the caged flock. This appeared to be due to a significant positive correlation among the lowest scoring birds on the floor.
Social behaviour of domestic animals III. Steers in small yards
Authors: McPhee C. P. , McBride G. , James J. W.
Published: September 2010

Behaviour observations and measurements were carried out on three classes of beef steers kept in yards under drought feeding conditions. The classes were (i) 2-year-old Brahman × Hereford crossbreds, (ii) 2-year-old Herefords and (iii) 3-year-old Herefords.

Animals of each class were placed in two groups and fed on low quality bush hay, one group ad lib. and the other on a restricted basis. An intermingled group comprised two animals from each class and was fed ad lib.

Fairly stable linear social orders were observed in each yard, social success depending mainly upon height. In the intermingled group, the crossbreds dominated the 3-year-old Herefords, which in turn dominated the 2-year-old Herefords.

Crossbreds bunted more actively and were more often disturbed at feeding during the day. They consequently consumed proportionately more feed at night than the Herefords.

Although high social ranking animals had priority at the feed trough there was no relationship between social rank and growth.

The orders in which the 2-year-old Herefords and crossbreds entered a crush were non-random. These orders appeared not to be related to social rank.
Studies of the inheritance of bovine serum transferrins
Authors: Gall G. A. E. , Berg R. T.
Published: September 2010

1. The transferrins in two cattle herds were studied by means of starch gel electrophoresis. Three phenotypes were observed in a Hereford herd and six in a Hybrid herd comprised of Galloway, Aberdeen Angus and Charolais breeds.

2. Gene frequencies were calculated for each herd. Great variation was found in the frequency of the transferrin alleles between breed and source within the Hybrid herd and between the Hybrid and Hereford herds. The frequencies of the transferrin alleles found in the cows in the Hereford herd were TfA= 0·467 and TfD= 0·533; those found in the cows in the Hybrid herd were TfA= 0·382, TfD= 0·506 and TfE= 0·112.

3. Progeny data were in general agreement with the three-allele theory of inheritance, although the data suggested that offspring in the Hybrid herd carrying the TfEallele occurred at a lower frequency than expected.

4. The possible relation of transferrin type to embryonic mortality was studied. The results were in general agreement with those of other workers, indicating a possible interaction between the genotypes of the foetus and dam.

5. The characteristics of the transferrin types and the postulated three-allele genetic mechanism for the control of the observed variation are discussed.
The effects of level of feeding of sows during pregnancy. II. Changes in body weight
Authors: Lodge G. A. , Elsley W. H. , MacPherson R. M.
Published: September 2010

1. Twelve groups of 3 litter-sister Large White gilts were given during three successive pregnancies a daily meal allowance of either 6 lb. (Group A) 3 lb. (Group B) or 3 lb. for 76 days followed by 6 lb. until parturition (Group C). During 8-week lactation periods all received the same daily allowance of 4 lb. meal plus 0·8 lb. for each piglet suckled.

2. Net weight gains during the three successive pregnancies respectively were: Group A, 114, 97 and 79 lb.; Group B, 11, 10 and 7 lb.; Group C, 47, 44 and 35 lb. The differences between groups were highly significant (P<0·001) and there was a significant parity interaction (P<0·05) in that Group A sows showed a significant decline in net weight gain from parity to parity whereas those of Groups B and C did not. No relationship was found between net weight gain and litter weight at birth.

3. Weight changes during the three successive lactation periods respectively were: Group A, –37, –41 and –36 lb.; Group B, 2, 14 and 4 lb.; Group C, –10, –14 and –5 lb. The differences between groups were significant to various degrees in different lactations. There was no relationship between weight changes during lactation and total litter weight at 3 weeks of age.

4. Overall weight changes from first service to third weaning were: Group A, 160 lb.; Group B, 72 lb.; Group C, 71 lb. The differences between Group A and Groups B and C were highly significant (P<0·001).

5. The implication of the results as an indication of feed requirements for reproduction is discussed.
Sources of variation in the uptake of a marker antibody by piglets
Authors: Perry G. C. , Watson J. H.
Published: September 2010

1. Homologous antibodies toSalmonella pullorumwere produced by immunising pigs between 100 and 200 lb. live-weight.

2. Standardised doses of antibody, extracted from whole serum after these pigs were slaughtered, were administered to 245 piglets by stomach tube during the first 24 hr. after birth.

3. The marked variation in uptake of the marker antibody, determined by direct agglutination tests on the blood serum of the dosed pigs, was chiefly due to variation between litters. This variation was attributed to maternal effects, associated with agents secreted in varying quantities into colostrum. Concentration of antibody in the dose administered to piglets, time elapsing between birth and dosage and differences between sire families, were subsidiary causes of variation. Possible mechanisms influencing efficiency of antibody absorption were examined and discussed.
Rearing of dairy cattle. 7. Effect of level of nutrition and body condition on the fertility of heifers
Authors: Leaver J. D.
Published: September 2010

One-hundred-and-seventy British Friesian heifers were individually fed from 6 weeks before to 6 weeks after artificial insemination on a diet of 90% maize silage and 10% decorticated groundnut in the dry matter. Three levels of nutrition were compared: 48, 55 and 62 g/day of digestible organic matter/kg live weight0·73, which gave mean growth rates of 0·34, 0·50 and 0·68 kg/day respectively. Pregnancy rates to first service were not significantly different, averaging 67, 69 and 65%. Heifers were given a body condition score at the time of insemination, and pregnancy rates corrected for level of nutrition were 42,72, 70 and 63% for heifers in poor, moderate, good or very good condition. For heifers in poor/moderate condition increasing the level of nutrition increased pregnancy rates and for those in good/very good condition pregnancy rates declined, but these effects were not significant.
Effect of season of the year and phase of the moon on puberty and on the occurrence of oestrus and conception in dairy heifers reared on high planes of nutrition
Authors: Roy J. H. B. , Gillies Catherine M. , Perfitt M. W. , Stobo I. J. F.
Published: September 2010

A study of the factors that influence the age at first oestrus has been made with 57 Friesian heifers reared on high planes of nutrition in a partially-controlled environment. Although animals born during the period of increasing daylength reached puberty approximately 2 months earlier than those born during decreasing daylength, there was also a marked influence of live weight at 182 days of age and of the phase of the moon at the time of oestrus.

Frequency of occurrence of first oestrus and of conception showed four distinct peaks at approximately 7-day intervals within the lunar cycle; this association between conception and lunar phase appeared to decline with increasing parity. Frequency of occurrence of artificial insemination, which reflected all suspected instances of oestrus, was also related to lunar phase. This effect of the lunar phase appears to be associated in the young heifer with 7-day cycles of oestrous activity positioned in time by the occurrence of the full moon.
The incidence of halothane sensitivity in British pigs
Authors: Webb A. J.
Published: September 2010

An adverse reaction in pigs to the anaesthetic halothane at approximately 8 weeks of age appears to be controlled by a single recessive gene affecting stress susceptibility, lean content and reproductive performance. In a survey of British nucleus herds, a total of 2998 pigs between 5 weeks of age and 28 kg live weight were given 3-min halothane tests during visits to 17 breeders or companies. There were no positive halothane reactions among 764 Large Whites from 7 herds. The frequency of positive reaction among 1538 Landrace from 14 herds averaged 11%, with a range from 0 to 23 % in individual herds. Frequencies in other pure breeds or synthetic lines varied from 0 to 88%. British and foreign breeds are compared, and the possibility of eliminating the halothane gene is discussed.
Feeding sows for specific weight gains in pregnancy and its effect on reproductive performance
Authors: Lee Pauline A. , Mitchell K. G.
Published: September 2010

Forty-five Large White × Landrace gilts were given food to realize energy intakes recommended by the Agricultural Research Council (1981) to attain maternal weight gains in pregnancy of either 40, 20 or 10 kg using a diet containing 125 g crude protein and 12·5 MJ digestible energy (DE) per kg over three parities. During a 3-week lactation period all animals were given a standard level of feeding. Maternal weight gains in pregnancy were much greater than those anticipated, for all treatments during each parity. The relationship between the actual and the predicted weight gains (kg) was the same for all three parities, actual AW = 22·62 + 0·71 predicted AW (R = 0·69). There was a large range of weight gains within treatments which was related to backfat thickness (P2 measurement (mm)) at conception in the second and third pregnancies, AW = 10·52 + 0·62 P2 measurement (R = 0·63) and to the change in P2 measurement, AW = 38·37 + 1·68 AP2 (R = 0·38) in the first pregnancy. The daily gain per MJ DE intake decreased wth parity and with decreasing energy intake. Numbers of piglets born and weaned were similar for all treatments; birth weights were also similar but there was an unexplained significant difference in piglet weaning weight in parity 2. There were no significant differences among treatments for either the total number or weights of piglets produced over the three parities.
The behaviour of pigs in a semi-natural environment
Authors: Stolba A. , Wood-Gush D. G. M.
Published: September 2010

In order to obtain a better knowledge of the behaviour of the domestic pig, a small population was established in 1978 near Edinburgh in an enclosure with several types of habitat, including woodland and bog. Over a 3·5-year period 13 different groups were studied with each group typically containing a boar, four sows, a young sub-adult boar and an immature gilt. The sow and her piglets were allowed to determine the time of weaning and, apart from providing food for maintenance and reproduction, handling was kept to a minimum. The behaviour of these pigs, which included most of the behaviour of the European wild boar, is described in a general manner for the non-specialist.
A note on the effect of early weaning on performance and carcass characteristics in Angus cross and Charolais cross steers
Authors: Butler-Hogg B. W. , Prescott J. H. D. , Lowman B. G.
Published: September 2010

Eight Angus cross and eight Charolais cross steer calves (out of Hereford × British Friesian cross dams) were weaned at turnout when 7 months old. Over a summer grazing period of 182 days these ‘early-weaned’ calves grew 30 to 35 % slower than eight comparable steer calves of each cross which continued to suckle their dams until 11 months of age. At housing, the early-weaned calves were 100 g/kg lighter, but this difference had no effect on growth rates or silage intakes during the 138-day finishing period. At the same age early-weaned steers had reduced hot carcass weight and dressing percentage but a similar proportion of fat in the forerib joint.
The use of natural shelter by hill sheep
Authors: Munro Joan
Published: September 2010

A small flock of 16 Blackface ewes occupying 40 acres of hill ground grazed as a fairly tight community. From observations over a complete year, 1960, it has been shown that sheltering behaviour was largely dependent on wind speed exceeding 24 m.p.h. Sheltering increased markedly at temperatures below freezing. Temperature above freezing, except for rapid falls in temperature exceeding 4° F., exerted little effect on sheltering. No relationship could be found between sheltering behaviour of the sheep and other factors which included rain, relative humidity, wind direction or season of the year.

It would appear therefore that the sensitivity of sheep to exposure is influenced more by wind speed than any other climatic factor.
Effect on production records of sex of lamb, twinning, and dam's age in a grassland flock
Authors: Donald H. P.
Published: September 2010

The effects of sex, twinning and age of ewe on birth weight, weaning weight and fertility have been studied in 5 years' records of a small grassland flock of Wiltshire × Blackface crossbred ewes with the object of providing provisional correction factors for these variables in recorded flocks under similar management. All these variables produced large effects in the flock studied. On birth weight these were; sex, 0·6 lb.; twinning, 2·1 lb.; hogg's lamb, 2·3 lb. The corresponding adjustments for weaning weight were 7 lb., 14 lb., and 11 lb. Ewes first bred as hoggs subsequently performed well.
A note on the effect of castration on the growth performance and concentrations of some blood metabolites and hormones in British Friesian male cattle
Authors: Galbraith H. , Dempster D. G. , Miller T. B.
Published: September 2010

Eight British Friesian bulls and eight steers were compared in terms of performance and levels of metabolites and hormones in circulating blood. Under conditions of generous nutrition the bulls grew significantly more quickly, exhibited a superior feed conversion efficiency and had lower levels of serum albumin and plasma urea and higher levels of serum growth hormone and prolactin than the steers. Differences in levels of plasma glucose and free fatty acids and serum total protein and insulin were not significant. It is suggested that the superior growth performance of the bulls is due, at least partially, to hormonally mediated differences in nitrogen metabolism that result in a greater deposition of lean tissue and hence increased weight gain.
Environmental and genetic causes of variation in production traits of Damascus goats. 1. Pre-weaning and post-weaning growth
Authors: Mavrogenis A. P. , Constantinou A. , Louca A.
Published: September 2010

Data on 1542 Damascus kids, collected from 1977 to 1981, were used to study environmental and genetic factors influencing pre-weaning and post-weaning growth traits of kids. Season of birth, type of birth, sex of kid and dam lactation number were the environmental factors investigated. Phenotypic and genetic parameters were estimated from paternal half-sib correlations. The average sire family size was 17·2 kids. Single kids were heavier at birth, at weaning and at 140 days of age than twins or other multiples (P < 0·01). Male kids were heavier (P < 0·01) and grew faster (P < 0·01) than female kids from birth to 140 days of age (4·7 and 4·2 at birth, and 29·2 and 24·6 kg at 140 days, respectively). Dam lactation number significantly affected pre-weaning growth, but had no effect on the post-weaning growth rate of kids.

Heritabilities for birth, weaning and 140-day weights, and pre-weaning and post-weaning growth rate, were 0·31 (s.e. 0·08), 0·27 (s.e. 0·07), 0·21 (s.e. 0·07), 0·16 (s.e. 0·06) and 0·22 (s.e. 0·07), respectively. Genetic correlations were mostly high and all positive, especially between weaning weight and 140-day weight (0·82 (s.e. 0·08)), and pre-weaning growth rate and 140-day weight (0·80 (s.e. 0·10)). The corresponding phenotypic correlations were also high and positive (0·71 and 0·67, respectively). No genetic antagonisms were found among the characters studied. Response to selection for post-weaning growth should be effective.
Evaluation of a model of the energy system of lactating and pregnant cows
Authors: Broadbent P. J. , Topps J. H. , Clark J. J. , Bruce J. M.
Published: September 2010

1. The model of the energy system of lactating, and pregnant, cows proposed by Bruce, Broadbent and Topps (1984) has been evaluated using data relating to 166 lactations for dairy cows and 48 lactations for beef cows. The cows in both sets of data were subjected to various nutritional and managerial regimes.

2. The discrepancies between observed and predicted values of milk (energy) and live weight were small, both as a proportion of the measured values and total energy intake. For Danish Black and White dairy cows the discrepancies for milk were virtually zero on both bases; those for live weight represented 0·020 of the total energy intake, or an over-prediction by 0·054 in late lactation. For Hereford × British Friesian beef cows, suckled by one or two calves, the discrepancies as a proportion of the total energy intake ranged from 0·005 to 0·051 for milk and 0·001 to 0·063 for live-weight change across the nutritional and managerial regimes.

3. It was concluded that the model of Bruce et al. (1984), which considers genetic potential for milk production and growth, nutritional (energy), reproductive and environmental status, may be used to predict milk yield and live-weight change simultaneously from food (energy) input.
The association between clinical mastitis and milk yield in dairy cows
Authors: Lucey S. , Rowlands G. J.
Published: September 2010

A study of 1514 lactations that occurred between 1977 and 1982 in 790 Friesian, Ayrshire and Holstein crossbred cows was undertaken. One thousand and eighty-four of these lactations were used to consider the association between the occurrence of clinical mastitis and changes in milk yield, and to illustrate a technique that enables the previous lactation history of a cow to be used for estimating changes associated with the disease.

The lactation curves were described using the model y(n) = anbe−cn from which values for peak yield, persistency, rate of decline at week 25, and recorded and extrapolated 305-day yield were calculated. A significant correlation between successive lactations of the same animal was observed for each of these variables. Pairs of successive lactations free from clinical mastitis were then compared by regression analysis with lactations in which the preceding lactation was free from the disease whilst the second lactation of the pair was infected.

Significant reductions in peak yield, recorded and extrapolated 305-day yield were found when mastitis occurred before the week of peak yield. A reduction in recorded 305-day yield was also observed when the disease occurred between peak and 10 weeks after peak. Mastitis later in the lactation had no significant effect.

The mean reduction in recorded 305-day yield of 540 kg when mastitis occurred before peak for a cow with a mean yield of 4830 kg, was higher than previous estimates. No evidence of recovery was observed in subsequent lactations that were free of clinical infection, indicating that once a cow has contracted mastitis it may not achieve its full milk-yield potential in the next lactation.
Oestrous synchronization in ewes: a comparison of prostaglandin F2α tham salt with a progestagen pessary
Authors: Henderson D. C. , Downing J. M. , Beck N. F. G. , Lees J. L.
Published: September 2010

An experiment was designed to compare saline, prostaglandin F2α tham salt and progestagen pessaries as agents for oestrous synchronization in mature cyclic ewes maintained under normal husbandry conditions. The effect of these agents on ewe fertility and lambing performance was also assessed.

One hundred and sixty Clun Forest ewes were allocated to one of four equal-sized treatment groups and received either two injections of saline given 9 days apart (group A), two injections of 10 mg (group C) or 20 mg (group D) postaglandin F2α tham salt given 9 days apart, or progestagen pessaries left in situ for 12 days (group B). Oestrous response, fertility and lambing performance were monitored thereafter. Oestrus occurred within 3 days of the end of treatment in 0·28, 0·98, 0·58 and 0·83 of ewes in groups A to D respectively, with return rates after a single mating of 0·15, 0·13, 0·25 and 0·33 respectively. There was no difference between treatments in lambing performance. These results indicate that two injections of either 10 or 20 mg prostaglandin F2α given 9 days apart is a less effective means of synchronizing oestrus in sheep than progestagen pessaries.
A note on the use of chromic oxide incorporated in a feed to estimate faecal output in ruminants
Authors: Curran M. K. , Leaver J. D. , Weston E. W.
Published: September 2010

Chromic oxide (Cr2O3) has been used for some time as an inert marker to estimate the faecal output of livestock. Although several methods of administration have been reported (Grassland Research Institute, 1961) the more widely used form would appear to be that of purchased gelatin capsules containing a suspension of Cr2O3 in maize oil. An alternative is to include the Cr2O3 in a concentrated feeding stuff. This method was widely used by early workers (e.g. Edin, Kihlén and Nordfeldt, 1944).
Studies on degradation and outflow rate of protein supplements in the rumen of dry and lactating Chios ewes and Damascus goats
Authors: Hadjipanayiotou M. , Koumas A. , Georghiades E. , Hadjidemetriou D.
Published: September 2010

Outflow rate of small particles from the rumen of dry and lactating Chios ewes and Damascus goats were measured in two separate trials using Cr-treated soya-bean meal (SBM). In another trial, the in situ degradation of fish meal (FM) and SBM in the rumen of Chios ewes and Damascus goats were measured. Outflow rate (per h) of small particles from the rumen of the two species was similar but higher outflow rates were observed in lactating than in dry animals (dry ewes 0·054, lactating ewes 0·086, dry goats 0·057, lactating goats 0·081). With the exception of dry-matter degradability of SBM at 6-h incubation periods there were no significant differences between ewes and goats in crude protein or dry-matter degradability of both supplements at all incubation intervals. Degradation measurements at various incubation periods and effective degradation values were different between supplements.