bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of environmental temperature on ruminal activity and blood urea of Merino sheep
Authors: Abou Akkada A. R. , El Ashray M. A. , Shethata O. , Yousri R. M.
Published: September 2010

Eight Merino wethers were used in an experiment designed to study the effect of heat stress on ruminal activity and blood urea of sheep newly introduced to Egypt. The sheep were exposed to 15° and 35°Cin aclimatic chamberwith controlled temperature and humidity. The animals were divided into two groups; the first received 100% of the TDN daily requirement and the second was given 125% of the recommended TDN. Rumen and blood samples were obtained from the animals before and at 2, 4, 6, 8 and 10 hr after feeding.

VFA concentrations in the rumen were higher in sheep fed on rations of high energy content. The levels of VFA at the low temperature were greater than at the high temperature. Ruminal ammonia and blood urea N concentrations in sheep maintained at the low temperature (15°C) were higher than those of the same animals when kept at the high temperature (35°C). This trend was more obvious at high levels of energy intake. It is suggested that the significant changes in rumen VFA, ammonia N and blood urea N in Merino sheep maintained under hot conditions can be considered as adjustments to changes in nutritional requirements in response to high environmental temperature.
The effects of varying the dietary calorie: protein ratios on the performance characteristics and carcass quality of growing pigs in the tropics
Authors: Babatunde G. M. , Fetuga B. L. , Oyenuga V. A.
Published: September 2010

Two trials were carried out to investigate the effects of increasing calorie: protein (C:P) ratios of high iso-nitrogenous diets on the performance characteristics, nutrient digestibility, carcass quality and organ weights of 67 growing pigs of the Yorkshire and Landrace breeds, reared in a tropical environment on concrete-floored pens from 9 to 56-8 kg live weight before slaughtering and grading. The dietary protein content was approximately 24 % of dry matter in all cases, and the C:P ratios ranged from 153 to 184 kcal digestible energy/g in both trials. Results showed no consistently significant differences in gain and feed intake due to increasing C:P ratio, but feed conversion ratios consistently improved with increasing C:P ratio. Digestible energy consumed per kg of body weight gained also increased with increasing C:P ratio. The nutrient digestion coefficients did not appear to be significantly affected by the C:P ratio. With respect to carcass quality measurements, there were nonsignificant differences in dressing percentage and average backfat measurements, but significant differences in percentage trimmed fat with increase in C:P ratio. The carcass length, loin eye area, and percentage lean cuts decreased as the C:P ratios increased, the last two showing significant differences only in the second trial. The organ weights showed no significant differences due to increases in C:P ratio.
Optimum selection intensity in breeding programmes
Authors: James J. W.
Published: September 2010

The present value of future genetic improvement in a closed population is taken to be proportional to the sum of discounted changes in the population mean. It is shown that, if T animals are available for selection and R is the discount rate per generation, the selection intensity which maximizes present value is a function of TR. If TR is greater than 15, under 10% of the population should be selected. It is then shown how T can be chosen to maximize profit if the value of genetic improvement and cost of testing are known. The theory is illustrated by a numerical example.
Selection of extremes
Authors: Abplanalp Hans
Published: September 2010

A method of selection for two or more traits is investigated, where the selected individuals have to be the highest performing for any one trait, but not necessarily for several traits. The efficiency of selection of extremes is contrasted with the methods of culling levels and tandem selection. It is shown to be superior to culling level selection when the proportion of individuals retained for breeding exceeds 0·5. At higher selection intensities, the effectiveness of selection of extremes falls between that of culling levels and tandem selection.
Effect of winter environment on growth of young beef cattle 1. Effects of exposure during winter to rain or wind and rain combined on performance of 9-month-old Friesian steers fed on two planes of nutrition
Authors: McCarrick R. B. , Drennan M. J.
Published: September 2010

Three experiments were conducted to compare the performance of 9-month-old Friesian steers wintered in three environments, (a) conventional cattle houses, (b) wind-sheltered roofless sawdust pads and (c) unsheltered roofless sawdust pads. Within each environment animals were fed on two planes of nutrition.

In each experiment, winter live-weight gains of animals accommodated on the three winter environments were similar as were weight changes during the subsequent four weeks at grass in Experiments 2 and 3.

No interaction on live-weight gain was found between plane of nutrition and winter environment. Health of outwintered animals was good throughout. The response to feeding barley with hay in these experiments (obtained by comparing low-plane with high-plane treatment groups) showed that on average 5·5 kg of barley dry matter were required to produce 1 kg of additional live-weight gain above that obtained from hay fed alone.
The effects of level of feeding during rearing and early pregnancy upon reproduction in young female sheep
Authors: Hamra A. M. , Bryant M. J.
Published: September 2010

Two hundred and forty Suffolk × (Cadzow Improver × Scottish Blackface) female sheep were housed at 4 months of age and average live weight (± s.d.) of 30·6 ± 501 kg, and divided into four equal treatment groups: HH, HL, LH and LL. They were group-fed such that HH and HL sheep were 39·7 ± 5·27 kg, and LH and LL were 35·6 ± 4·64 kg, at puberty, which was recorded in all sheep. There were no differences in average date at puberty.

After puberty the sheep were gradually transferred to different levels of feeding by the time of mating with fertile rams at the second oestrus such that HH and LH were group-fed 1·50, and HL and LL 0·75 of maintenance requirement. The sheep were slaughtered at return or 25 ± 3 days after mating.

The proportion of sheep with live embryos was 0·48,0·40,0·50 and 0·41 for HH, HL, LH and LL groups respectively (NS). Ova wastage was 0·59, 0·68, 0·51 and 0·59 for the treatments, with statistically significant differences in losses between treatments in sheep with two corpora lutea (P<0·05). Ovulation rate also differed between treatments (HH > HL, P < 0·01; HH > LH and LL, P < 0·05). Differences occurred between treatments in the proportion of multiple cycles between first and second oestrus (P<0·05), and HL sheep had a greater proportion of sheep failing to return to service but without embryos (HH>HL, P<0·05). The pooled results showed that pregnant sheep were heavier at 4 months of age (P < 0·05), but not at mating, than non-pregnant sheep. Sheep with two corpora lutea were more likely to be pregnant than sheep with one corpus luteum (P < 0·05).
The effect of pattern of concentrate allocation on milk production from autumn-calving heifers
Authors: Gordon F. J.
Published: September 2010

Forty-four British Friesian, first-lactation heifers were used in a randomized block experiment over a 2-year period to examine the effects of two patterns of concentrate allocation during the post-calving, indoor feeding period. The animals, mean calving date 17 October (s.d. 15 days), were offered concentrates either on a high-low system consisting of 80kg/day for the first 90 days of lactation and thereafter 5-4kg/day, or on a uniform system in which 6-8 kg/day was offered from calving until going to pasture (mean of 182 days). In addition, all animals received access ad libitum to grass silage, with a mean dry-matter content and digestible organic matter in the dry matter value of 218 and 679g/kg respectively. During the 1st year all 22 animals were housed as a single group, but in the 2nd year the animals were housed in individual stalls and silage intakes recorded for all replicates. In each year all animals grazed as a single group at pasture without supplementary concentrates.

Total concentrates consumed were 1163 and 1187 (s.e. 19·4)kg for the high-low and uniform treatments respectively. Although the animals on the high-low treatment reached a higher peak milk yield, there were no significant differences in milk yield over the winter period, 3257 and 3311 (s.e. 41·5) kg, or total lactation, 4862 and 4886 (s.e. 80·6)kg, for the high-low and uniform treatments respectively. The animals on the high-low treatment, however, were significantly lighter in body weight at the end of the winter but there was no difference between treatments at the end of lactation. Milk composition data are also presented.
A study of body weight from birth to 1 year of age in European-zebu crossbred cattle in Ethiopia
Authors: Kebede B. , Galal E. S. E.
Published: September 2010

Body weights at birth, 90 days, 180 days and 1 year of age were analysed in 620 calves, the offspring of sires of the Friesian, Jersey and Simmental breeds, and of dams of three indigenous zebu breeds, namely Barka, Boran and Horro, at four diverse locations in Ethiopia.

Breed of sire, breed of dam and location all significantly affected weight. Progeny of Friesian and Simmental sires were similar in weight but both were heavier than the progeny of Jersey sires, their weight being, respectively, 25·0,24·9 and 21·2 kg at birth; 88·0, 84·6 and 74·9 kg at 90 days; 151·7, 150·6 and 135·4 kg at weaning at 180 days; and 220·6,224·8 and 193·3 kg at 365 days. Barka crosses were heaviest and Horro lightest. Mean weight for progeny from Barka, Boran and Horro dams was, respectively, 24·0, 24·6 and 22·5 kg at birth; 85·2, 83·8 and 78·5 kg at 90 days; 149·6, 148·0 and 140·1 kg at 180 days; and 233·7, 208·1 and 196/9 kg at 365 days. Dam breed × location interaction was significant except at birth, and sire breed × dam breed and sire breed × location interaction were significant at 90 days of age. In a comparison of Friesian and Simmental, the Friesian sires interacted relatively more favourably with the Barka dams, and the Simmental with the Boran. The Jersey was also relatively better with the Boran crosses, compared with either the Barka or the Horro crosses. By 1 year of age Jersey crosses were at a relative (but insignificant) advantage in body weight at the hottest location.
An evaluation of red clover silage for beef production
Authors: Steen R. W. J. , McIlmoyle W. A.
Published: September 2010

Two experiments have been conducted to compare wilted, formic acid-treated red clover and unwilted, formic acid-treated grass silages for beef production, and to examine the effects of digestibility of red clover and level of concentrate supplementation on food intake and animal performance.

In experiment 1, 12 groups of four British Friesian steers (initial live weight 229 kg) were given red clover silages of high and low dry-matter digestibility (0·70 and 0·60 respectively) and grass silage (0·71) ad libitum for a period of 11 weeks. Silage dry-matter intake and live-weight gain for the steers given red clover of high digestibility, red clover of low digestibility and grass silages were 7·75, 0·89; 6·91, 0·69; and 5·59, 0·59 kg/day respectively.

In experiment 2, 12 groups of four British Friesian steers (initial live weight 332 kg) were given red clover silage with a dry-matter digestibility of 0·63 and grass silage with a value of 0·76 ad libitum, either unsupplemented or supplemented, with 2 kg/day of fortified barley per head for a period of 19 weeks. Silage dry-matter intake, live-weight gain and carcass gain were 8·52, 0·63, 0·32 and 6·98, 0·78, 0·43 kg/day for the unsupplemented and supplemented red clover silage treatments, and 6·82, 0·59, 0·31 and 5·75, 0·75, 0·44 kg/day for the unsupplemented and supplemented grass silage treatments respectively. The performance of the cattle offered red clover silage was similar to that of cattle offered grass silage of 0·12 higher digestibility, largely as the result of higher dry matter intakes achieved on red clover silage.
The effect of various factors on the efficacy of tylosin as a growth promoter in clinically healthy pigs
Authors: Jones P. W. , Tarrant M. E.
Published: September 2010

Nineteen field trials were conducted in eight 1 uropean countries to examine the effects of tylosin, administered in the food at a level of 20mg/kg to healthy pigs under good management conditions. Average daily gain and food conversion ratio were improved by 33 g and 0·17 respectively over untreated control animals, with no change in average daily food consumption. These improvements in growth performance were similar in the grower and finisher phases, and the response to tylosin was not affected by sex, initial weight or year. Absolute responses in average daily gain and efficiency of food utilization were constant, whatever the level of performance in the controls.
Plasma concentrations of progesterone, oestradiol-17β and luteinizing hormone in relation to repeat breeding in buffalo (Bubalus bubalis)
Authors: Arora R. C. , Pandey R. S.
Published: September 2010

Progesterone, oestradiol-I7β and luleinizing hormone were measured by radioimmunoassay in plasma samples collected daily or on alternate days following insemination in six ‘repeat breeder’ buffaloes. The endocrine profiles in these animals demonstrated that a variety of temporary disturbances in behaviour of these circulating hormones resulted in reproductive failure.
The utilization by calves of formaldehyde-treated maize silages and the response to supplementary protein
Authors: Kaiser A. G. , Osbourn D. F. , England P. , Dhanoa M. S.
Published: September 2010

Four silages were prepared from whole crop maize, each receiving additives of 21 1 formic acid per t fresh crop, and 0, 14, 27 or 53 g formaldehyde per kg crude protein in the crop. These silages, together with 19·6 g urea per kg dry matter, were offered ad libitum for 83 days to 60 British Friesian steer calves, initially 99 kg live weight, either alone or with groundnut or fish meal to raise the dietary crude protein content by 27 g/kg dry matter.

Formaldehyde treatment restricted silage fermentation, increased silage and dry-matter intake and live-weight gain, but reduced digestibility, so digestible organic matter and digestible energy intakes were unaffected. Much of the increase in live-weight gain appeared to be due to an increase in gut fill, as carcass weight was not significantly affected by formaldehyde treatment. There was no improvement in the utilization of dietary nitrogen, but there was some evidence that formaldehyde treatment may have increased the proportion of muscle in the carcass.

Supplementation with protein improved intake, nitrogen retention, feed conversion ratio, live-weight gain and carcass weight. The improvement in intake and food conversion ratio occurred mainly on the control silage, there being little effect on the formaldehyde-treated silages. Fish meal supplementation increased the digestibility of organic matter, cellulose and energy, and was more effective in improving food conversion ratio than groundnut meal. There were no significant differences between diets in the proportion of dietary nitrogen retained.

It was concluded that the scope for the use of formaldehyde, when ensiling maize for use in diets for young calves, appears to be limited.
The use of teat-size measurements or calf weaning weight as an aid to selection against teat defects in cattle
Authors: Frisch J. E.
Published: September 2010

Measurements of the median diameter of all teats were recorded within 2 days of calving on 892 cows from eight breeding lines. Teats with a median diameter of ≥35 mm were classed as bottle teats. Their incidence varied from zero in a Hereford line to 0-55 in a Sahiwal crossbred line. In all lines, except the Hereford line, bottle teats were the most important single cause of mortality, up to 2 months of age, of calves that were born alive. However, mortalities became disproportionately high only when all four teats were classed as bottle teats.

Of calves that survived to weaning, those born to cows with at least one bottle teat had heavier live weights at weaning than those born to cows without bottle teats. Consequently, more calves were selected for high growth rate as potential sires from cows with bottle teats than from cows without bottle teats. This, combined with the observation that bottle teats occurred only after at least two calvings, is likely to reduce progress towards elimination of the defect through culling. However, indirect culling of the defect through any effect on calf performance is completely ineffective and uneconomic, and it is recommended that cows be culled directly for the defect in the year in which it first appears.
Laboratory evaluation of ensiled poultry litter
Authors: Hadjipanayiotou M.
Published: September 2010

Poultry litter collected from a commercial broiler house, bedded with wood shavings, was used. The material was screened and ground before it was ensiled either alone or with other agricultural by-products, namely chopped barley straw, a mixture of weeds and grapefruit peels. The digestible organic matter in the dry matter value in vitro (0·39) for litter was comparable with that for straw and weeds. Of the total nitrogen (36·3 g/kg dry matter), 0·19 was ammonia-nitrogen and 0·77 protein-nitrogen. Digestible energy and crude fibre in the litter were 7·19 MJ and 334 g/kg dry matter, respectively. Addition of poultry litter at ensiling resulted in significant increases in nitrogen and ash content of the original mixtures. Inclusion of sodium hydroxide in fermented and non-fermented mixtures elevated digestible organic matter in the dry matter values in vitro by 0·19 and 0·13, respectively; the crude fibre concentration was lowered. All initial mixtures were free of lactic acid and were positive for the pathogen Proteus when tested. Unlike crude fibre, fatty acid and free ammonia, which were increased after fermentation, digestible organic matter in the dry matter and pH values were decreased. Ensiling killed the pathogen Proteus in the majority of the silages tested. The silages had a pleasant aroma and colour, and were consumed by Chios sheep.
Maternal performance of oxford and suffolk breeds, of sheep, and their crosses
Authors: Fahmy M. H.
Published: September 2010

The proportion of ewes lambing of those exposed to the ram, litter size and weight at lambing, and at weaning, pre-weaning lamb mortality and changes in ewe weight during suckling, were studied in 326 ewes (931 lambings) representing two pure breeds, Oxford and Suffolk, and four crossbreds, Oxford♂ × Suffolk♀, Suffolk♂ × Oxford♀, North Country Cheviot♂ × Oxford♀ and Cheviot♂ × Suffolk♀, mated to purebred and crossbred rams during 9 years. The proportional fertility in the Oxford and Suffolk ewes (0·82 and 0·85 respectively) was lower than that of Suffolk × Oxford (0·93), Oxford × Suffolk (0·94), Cheviot × Oxford (0·88) and Cheviot × Suffolk (0·88) ewes. Litter sizes of Suffolk ewes at birth and at weaning were 1·6 and 1·3 lambs, 0·3 (0·22) and 0·3 (0·27) lambs largeir than those of the Oxford ewes, respectively. The corresponding figures for litter weight were 1·29 kg (0·22) and 11·8 kg (0·36). Oxford ewes lost 0·10 of their weight during nursing compared with 0·14 for the Suffolk and the two reciprocal crosses. The estimates of heterosis in litter size and litter weight at birth were 0·085 and 0·082, and at weaning were 0·13 and 0·18 respectively.

The results showed that Oxford crosses were better in performance than the pure Oxford, whereas the Suffolk crosses were similar in performance to the pure Suffolk, except in the proportion of ewes lambing of those exposed and pre-weaning mortality, in which the crosses were 0·07 and 0·20 superior to the pure Suffolk, respectively.

Breed of sire had a significant effect on litter weight at birth and at weaning, whereas the interaction breed of sire × breed of dam was a significant source of variation on litter size and litter weight at birth and at weaning. Litter performance at birth was significantly lower in 2-year-old ewes and in ewes sired by 3-year-old or older rams than in other age groups
A note on the effects of the ratio of protein to digestible energy and digestible energy concentration in the diet on performance and nitrogen metabolism of piglets weaned at 21 days of age
Authors: Newport M. J. , Keal H. D.
Published: September 2010

Piglets were weaned at 21 days of age, and given diets containing 13·5 or 17·0g crude protein per MJ digestible energy and either 14·7 or 16·8 MJ digestible energy per kg in a 2 × 2 factorial experiment until 56 days of age. There was no effect on performance or food intake when the diets were offered ad libitum, but energy intake was increased with the higher concentration of dietary energy. The higher levels of both protein and energy improved performance in a metabolism experiment with food intake restricted to 0·80 ofad libitumintake, and the higher protein level increased nitrogen retention (g/day per kg live weight) and plasma urea nitrogen. These results suggest that the level of food intake can affect the response to changes in dietary energy and protein concentrations, and indicate that conclusions from metabolism experiments using restricted feeding may be inappropriate under other conditions.
A comparison of boars, gilts and castrates for bacon manufacture 3. Consumer reaction, to bacon from boars and castrates and an economic evaluation of a non-castration policy for bacon manufacture
Authors: Smith W. C. , Ellis M. , Clark J. B. K. , Innes N.
Published: September 2010

Consumer reaction to bacon from boars and castrates, whose production and processing characteristics were known, was determined in 122 households consisting of 238 respondents. On a seven-point scale the mean scores for six organoleptic characteristics were similar for each sort of bacon relative to that usually purchased. A proportion of 0·045 of cooks scored boar bacon at the point of strongest rejection (unappetizing aroma) during cooking but less than 001 considered that the flavour was very much stronger than their usual bacon. Few respondents marked boar bacon inferior to their usual bacon for eating characteristics. On a comparative basis the frequency distribution of scores for flavour, juiciness and pleasantness of aroma on the plate was slightly in favour of castrate bacon but was of little importance. Using the production and processing data obtained and accepting no adverse consumer reaction to boar bacon, a financial advantage to the producer of entire male pigs for bacon manufacture over castrates was demonstrated (£2·95). However, if the retailer should not reward the curer for the extra leanness of the boar then the curer might be at a financial disadvantage.
The effects of food intake in gestation on sows lactating for 14 days
Authors: Walker N.
Published: September 2010

Ninety-two gilts in replicates of four littermates were mated at puberty at a mean live weight and age of 95 kg and 191 days respectively. The littermates were allocated at random to one of four food allowances (kg/day) during four successive gestations: (A) 1·5, (B) 2·0 in parity 1 followed by 1·5 in subsequent parities, (C) 20 and (D) 2·5. A diet calculated to contain 12·7 MJ digestible energy per kg was fed throughout gestation, the 2-week lactation and from weaning to conception.

The numbers of sows which conceived at parity 5 when the experiment terminated were 10, 12, 13 and 16 for treatments A to D respectively. Sow live weight at conception differed significantly (P< 0·01) from parity 2 onwards: the maximum live weights of sows on treatments A and B did not exceed 130 to 135 kg, but the live weights of sows on treatment D continued to increase to reach 195 kg at the end of the experiment. The in vivo skin plus subcutaneous fat thickness at the P2 location differed significantly (P< 0·001) between treatments from parity 2 onwards, decreasing by 3 mm in treatment A and increasing by 6 mm in treatment D from the start of the experiment to conception at parity 4. The interval from weaning to conception was significantly (P< 0·05) lower in treatment B in parity 2. This was the only significant effect and was contrary to the tendency for the interval to increase as the food allowance in gestation was decreased. The numbers of pigs born alive, stillborn or weaned (including fostered pigs) were not significantly affected by treatment. Birth weight and post-natal growth rates were significantly (P< 0·05) increased after parity 1 as gestation food allowance increased, with the exception of the post-natal growth rate in parity 3. Overall birth weight was increased by 018 kg per pig and weaning weight by 0·93 kg per pig on treatment D compared with treatment A.
Factors affecting patterns of development and their assessment
Authors: Seebeck R. M.
Published: September 2010

The effect of rate of growth on the development of animals is examined in terms of it being related to variation from a pattern of development described by the allometric hypothesis. For this purpose, aliometry is expressed in terms of an extension to the shape/size concept originally proposed by Mosimann.

It is shown that such an effect of rate of growth would bias estimates of the development pattern, depending on the experimental design. However, within the framework of the method, a procedure for both removing the bias and actually estimating the effect of rate of growth on development is available.

A previously described test for one type of deviation from aliometry is shown to be incorrect by simulation.

An alternative test for the adequacy of the allometry hypothesis is developed, based on factor analysis of residual matrices from multivariate analysis of variance (the latter being used so that effects of treatment and concomitant variables can be taken into account).
A note on the effect of dentition and age in sheep on the intake of herbage
Authors: Newton J. E. , Jackson Caroline
Published: September 2010

The intake of ten 5-year-old Masham ewes with good teeth, five 7-year-old Mashams with poor teeth and nine 10-year-old ewes with poor teeth was measured when they were offered long (35·1 cm) or short grass (3·8 cm) outdoors or poor quality hay indoors. The young ewes ate significantly more grass and hay than the old ewes, but the difference in daily intake was greater with long grass (1473 v. 751 g organic matter per head) and with hay (895 v. 421) than with short grass (617 v. 407). The intermediate age ewes ate as much of the long grass and of the hay as the young ewes, but less of the short grass. This suggests that age influenced intake more than did tooth condition, except when short grass was offered.

Within the oldest but not within the intermediate group of ewes, there was a significant correlation between the number of incisors and organic matter intake, except with the long grass, but there was no correlation between the number of cheek teeth and intake. When offered hay, the only group with a reduced in vivo digestibility was the intermediate group of ewes, the other two groups having a similar digestibility.

There was no correlation between number of incisors or number of molars and in vivo digestibility.
Comparative performance of F1Friesian × Zebu heifers in Ethiopia
Authors: Alberro M.
Published: September 2010

The performance of 200 F1Friesian ♂ × zebu ♀ and 90 zebu heifers on 14 dairy cooperative farms near Addis Ababa was compared over a 2-year period. The farms varied in management and feeding but in general the standards were low. Each farm had zebu and Friesian × zebu cows given the same management and feeding. Measurements were made of milk production traits of economic importance, including physiological and behavioural factors important for management purposes.

The Friesian ♂ × zebu ♀ crossbred heifers showed an advantage in having an earlier age at puberty and at first calving, higher milk production, longer lactations, better disposition at milking and better reproductive performance. The calves from these crossbred heifers were larger at birth but there were more problems at calving. The zebu heifers withstood better the two periods of drought that occurred during the study. No significant differences were found in disease incidence, parasitic resistance, mastitis incidence or mortality. The interval between oestrus was normal in the F1heifers but longer in the zebus. The duration of gestation was much longer in the zebus (mean 291 days). The duration of oestrus was 4·5 h for the zebu and 10·0 h for the F1heifers, the latter being-much longer than the mean of 7·4 h reported in the literature. The F1heifers showed the first oestrus after calving much sooner than did the zebus.
Lactation performance, herbage intake and lamb growth of Scottish Blackface and East Friesland × Scottish Blackface ewes grazing hill or improved pasture
Authors: Doney J. M. , Peart J. N. , Smith W. F. , Sim D. A.
Published: September 2010

Scottish Blackface (BF) and East Friesland × Scottish Blackface (EFX) ewes rearing single or twin lambs grazed for 14 weeks of lactation on two different pasture types in two consecutive years. Mean daily milk production, live-weight change and herbage intake of the ewes and live-weight gain of the lambs were measured each week.

In the first year the ewes grazed a ryegrass/clover sward. There were significant differences in milk production associated with breed of ewe and number of lambs reared. Peak yields, achieved in the 3rd or 4th week, reached 2·25, 2·5 and 3·25 kg/day for BF ewes with a single lamb and EFX ewes with single or twin lambs, respectively. Corresponding yields in the 14th week were 0·5, 1·35 and 1·15 kg/day. Live weight of ewes in all groups declined during the first 2 weeks but recovered by week 6. Herbage intake increased in all groups until the 8th week and then declined much more rapidly in the BF than in the EFX ewes. Lamb growth was related to milk intake to give weaning weights of 31·5, 39·0 and 29·0 kg, respectively.

In the second year, when ewes grazed a hill pasture dominated by an AgrostislFestuca community, differences in milk production, though significant, were smaller than in the previous year. Peak yields were 2·1, 2·25, 2·25 and 3·1 kg/day, respectively, for BF ewes with single or twin lambs and EFX ewes with single or twin lambs. At 14 weeks, yields had fallen to between 0·6 and 1·0 kg/day. The patterns of live-weight change and food intake were similar to those in the previous year. The EFX ewes consumed more food than BF ewes throughout lactation, particularly in the second half. Lamb growth rate was again related to milk supply and was lower than in the previous year. Weaning weights were 31·0, 25·5, 34·5 and 27·0 kg for single or twin lambs reared by BF or EFX ewes, respectively.
A study of the relationship between plane of nutrition during lactation and certain production characteristics in autumn-calving suckler cows
Authors: Somerville S. H. , Lowman B. G. , Edwards R. A. , Jolly G.
Published: September 2010

Hereford ♂ × British Friesian ♀ cows that had calved in September/October and were suckling mainly Charolais ♂ × calves were offered individually one of three planes of nutrition based on their estimated maintenance requirement during their first 150 days of lactation.

The mean daily intakes of metabolizable energy were 95·8, 71·5 and 52·1 MJ for the high, medium and low planes of nutrition respectively. Data were collected from 122 lactations. The mean 150-day cumulative milk yields of the cows were 1 355, 1 258 and 1 187 kg for the high, medium and low planes of nutrition respectively (P < 0·001). A i-kg increase in calf birth weight was associated with an increase in 150-day cumulative milk yield of 14·7 ± 2·17 kg (P < 0·001). Losses in live weight and condition score were significantly greater for cows given the low plane of nutrition during lactation (P < 0001).

Although there was a significant (P < 0·01) positive correlation between the growth rate of the calves and their dams' nutritional level during the winter there was evidence of compensatory growth at grass, since by the time of weaning in August, the plane of nutrition of the dam during the winter had no significant effect on the weight of the calves.

The experiment demonstrates that energy-deficient beef cows will attempt to maintain milk production at the expense of body reserves and that when supplementary solid food is made available to the suckled calves, their weaning weights are unaffected by the plane of nutrition of the dam during the winter.
Genetic variation in the efficiency of energy utilization by the fattening pig
Authors: Foster W. H. , Kilpatrick D. J. , Heaney I. H.
Published: September 2010

An analysis was performed on data from three breeds recorded at the Pig Testing Station in Antrim in order to estimate and apportion variation in the measure of efficiency considered here, namely the daily food consumption after allowance had been made for maintenance and production requirements and other fixed effects. Results suggest that a considerable proportion of the variation in residual consumption is due to genetic causes (h2 = 0·3) and that selection to exploit this variation would result in an appreciable reduction in food costs. There were indications of considerable litter effects upon the trait.
Changes in body composition relative to weight and maturity of large and small strains of australian merino rams. 4. Fat depots and bones
Authors: Butterfield R. M. , Thompson J. M.
Published: September 2010

Maturing patterns are established for the weight of bones relative to the weight of total bone and for the weight of fat depots relative to the weight of total body fat in two strains of Merino rams of different mature size. The maturing coefficients for all bone and fat depots are tabulated.

In the mature animals the partitioning of fat in each strain was similar, except for scrotal fat which was more abundant in the smaller strain. The maturity patterns of the depots were not different for the strains and also not different from the pattern of total fat, except in the case of scrotal fat. Accordingly, comparisons of the partitioning of fat were similar at equal maturity to the comparisons made at equal weight.

The distribution of weight among the bones was similar at maturity for both strains. However, unlike the fat depots, the individual bones had maturity coefficients which were mostly different from that of total bone. The limb bones, with the exception of the scapula, were early maturing relative to total bone. Accordingly, when compared at equal weight, limb bones, except the scapula, were a higher proportion of total bone weight in the larger strain and the differences between the strains were reduced when compared at equal maturity.

A summary of conclusions from this series of papers shows that tissues and organs had similar maturity coefficients in both strains of rams, and that stage of maturity was important in comparisons of proportions of tissues which have maturity coefficients which differed greatly from 1·0, but of little consequence where the maturity coefficient was close to 1·0
Energy-budget strategies for growth in mammals and birds
Authors: Kirkwood J. K. , Webster A. J. F.
Published: September 2010

The concepts of metabolic time and size are used, respectively, to compare maturing time and energy exchanges during growth in homeotherms. Maturation rate, expressed per unit of mature size (A1/4) is relatively constant for mammals, irrespective of attempts by man to select for rapid growth. Precocial birds mature more rapidly, however, and altricial birds more rapidly still. These differences are explained in terms of different patterns of energy exchange. It is proposed that maturation time is ultimately determined by size-related constraints on rate of metabolism during growth.
Comparative performance of six Holstein-Friesian × Guzera grades in Brazil 1. Gestation length and birth weight
Authors: Lemos A. M. , Teodoro R. L. , Barbosa R. T. , Freitas A. F. , Madalena F. E.
Published: September 2010

Gestation length and birth weight of 939 calves born at Santa Monica Experimental Station, Valenc, a, State of Rio de Janeiro, were studied. The calves were of six red and white Holstein-Friesian (HF) × Guzera (G) grades: 1/4, 1/2, 5/8, 3/4, 7/8 and ≥ 31/32.

As the grade × sex interaction for birth weight was significant, data for each sex were analysed separately. A model, including the effects of grade, year-season of birth, grade × year season interaction and age of dam as a covariate, resulted in the following least-square means for the six grades in the above order (± s.e.): gestation length for cows carrying male calves, 290·0 (± 0·9), 281·2 (± 0·9), 285·3 (± 0·8), 278·8 (± 0·9), 280·5 (± 0·9) and 279·3 (± 0·9) days; gestation length for female calves, 287·5 (± 0·9), 280·1 (± 1·0), 285·3 (± 0·9), 274·5 (± 1·1), 279·2 (± 0·9) and 276·4 (± 1·0) days; birth weight for males, 34·6 (± 0·7), 28·6 (± 0·8), 34·2 (± 0·7), 32·4 (± 0·7), 35·0 (± 0·7) and 34·7 (± 0·7) kg; birth weight for females, 29·9 (± 0·6), 29·5 (± 0·7), 33·4 (± 0·6), 31·9 (± 0·7), 33·6 (± 0·6) and 32·6 (± 0·6) kg.

Direct (g1) and maternal (gM) breed additive effects (HF - G), and direct (h1) and maternal heterosis (hM) were estimated. The estimates of g7, gM, h1 and hM were respectively, for gestation length for male calves: -21·5 (± 1·9), 10·6 (± 2·1), 1·5 (± 1·8) and -1·6 (± 11) days; for gestation length, for female calves: -21·9 (± 2·1), 14·6 (± 2·5), 5·7 (± 2·1) and -1·5 (± 1·2) days; for birth weight of male calves: -3·5 (± 1·5), 7·1 (± 1·8), -0·6 (± 1·5) and 1·0 (± 0·9) kg; and for birth weight of female calves: 4·7 (± 1·4), 4·1 (± 1·6), 2·8 (± 1·3) and 2·0 (± 0·8) kg. The difference in birth weight between males and females was 4·7 (± 0·9) for G-sired calves and 0·8 (± 0·4) for HF-sired calves.
Comparative Performance of Six Holstein-Friesian × Guzera grades in Brazil 2. Traits related to the onset of the sexual function
Authors: Teodoro R. L. , Lemos A. M. , Barbosa R. T. , Madalena F. E.
Published: September 2010

Age and weight at puberty, age at first conception and number of services per conception of 90 females at Santa Monica Experimental Station, Valencia, State of Rio de Janeiro, were studied. The females were of six red and white Holstein-Friesian (HF) × Guzera (G) grades: 1/4, 1/2, 5/8, 3/4, 7/8 and ≥ 31/32.

A model (1) including the effects of grade and season of birth resulted in the following least-squares means for the six grades in the above order (± s.e.): age at puberty, 770 (± 17), 725 (± 18), 799 (± 26), 788 (± 23), 777 (± 17) and 803 (± 24) days; weight at puberty, 309 (± 8), 334 (± 9), 316 (± 13), 311 (± 11), 303 ((± 9) and 298 (± 12) kg; age at conception, 865 (± 19), 773 (± 19), 867 (± 31), 808 (± 25), 852 (± 22) and 837 (± 25) days; number of services per conception, 1·9 (± 0·2), 1·7 (± 0·2), 1·5 (± 0·3), 11 (± 0·2), 1·6 (+ 0·2) and 1·3 (± 0·2).

A second model (2) was fitted, including the effects of season of birth, direct (g1) breed additive effects (HF - G) and heterosis effects (hl). g1 and h1 were estimated by the partial regression coefficient of the traits studied on, respectively, the expected HF gene frequency and the expected heterozygosity of the females. The estimates of g7 were not significantly different from zero except for age at first conception (g7 = -102 (s.e. 46) days) (P < 0·05). Heterosis effects were significant for age at puberty (h1 = -86 (s.e. 34) days), weight at puberty (h1 = 44 (s.e. 17) kg) and age at first conception (h1 = —119 (s.e. 37) days). These three estimates of h1 amounted, respectively to —0106, 0151 and —0·132 of the estimated mean of the parental breeds.

F-tests on the extra variation due to fitting model 1 after model 2 were not significant (P < 0·05) indicating that epistasis or other genetic effects, not included in model 2, were of little importance for the traits studied.
Effects of plane of nutrition and environmental temperature on the growth and development of the early-weaned piglet 1. Growth and body composition
Authors: Close W. H. , Stanier M. W.
Published: September 2010

1. Eighteen litters of piglets were weaned at 14 days of age and reared for a further 3 weeks at environmental temperatures of 18, 23 or 28°C. At each environmental temperature three levels of feeding were used. The changes in body composition of the piglets were studied by the comparative slaughter procedure, littermates being analysed at birth, and at 14, 22 and 36 days of age. For comparison, the bodies of suckled piglets of similar weights and ages were also analysed.

2. In the 2 to 3 day period following weaning, body weight decreased, with the greatest reduction being 0·28 (s.e. 002) kg at 18°C. Following this, body weight gain was dependent on both environmental temperature and level of feeding, although at any given level of food intake there was little difference between the values at 23 or 28°C.

3. There were marked changes in the chemical composition of the carcass in relation to the different temperature/feeding level combinations. The most variable component was fat. In the period following weaning there was considerable mobilization of fat, especially at the lower temperatures and feeding levels. The fat content of the early weaned piglets at 36 days of age (68 to 103 g/kg) was significantly less than that of the suckled piglets (169 g/kg) (P < 0·01). The decreases in fat content were accompanied by increases in the dry-matter content of the carcass.

4. The protein content of the carcass remained relatively independent of the different treatments, ranging from 140 to 164 g/kg for the early-weaned piglets, compared with 139 g/kg for those that had suckled their mothers.

5. The differences in the growth and body composition of the early-weaned piglet are discussed in relation to an inadequate food intake following weaning, to changes in nutrient supply and to variations in the climatic environment.
Studies on lambs from lines genetically selected for low and high copper status 1. Differences in mortality
Authors: Woolliams Carol , Suttle N. F. , Woolliams J. A. , Jones D. G. , Wiener G.
Published: September 2010

Mortality and its causes were studied during two consecutive years in a total of 934 lambs. The lambs were from two lines of sheep genetically selected for low (L) and high (H) concentrations of copper (Cu) in plasma within an interbred Scottish Blackface × Welsh Mountain population and from unselected Scottish Blackface (B) and Welsh Mountain (W) breeds. The lambs grazed improved hill pastures. Half of the lambs in each line or breed were given an oral Cu supplement by 7·5 weeks of age.

Mortality from birth to 24 weeks in H was less than half that in L; mean proportional mortalities were L 0·28, H 0·12, B 0·37 and W 0·07, with a similar distribution in each year. Swayback accounted proportionately for 0·26 deaths in year 1, but proportionately for only 0·02 in year 2. The majority of other losses involved a variety of microbial infections.

Genetic type (W < H < L < B) was a major determinant of, and Cu supplementation a protection against, swayback and non-swayback losses. For non-swayback losses L lambs were about twice (P< 0·01) and B lambs about four times (P< 0·001) more vulnerable than H and W lambs respectively. Unsupplemented lambs were more than twice as vulnerable to non-swayback causes of death in the 1st year (P< 0·05) and four times as vulnerable in the 2nd year (P< 0·01) as were Cu-supplemented lambs. There were no cases of swayback in supplemented lambs even though Cu treatment was in some lambs as late as 7·5 weeks after birth.

Such marked differences in mortality rate, particularly between the selected lines, had not been apparent in the 5 years preceding pasture improvement, suggesting a genotype × environment interaction affecting survival.

The results provide the first definitive evidence that decreased resistance to infection is a clinical consequence of ovine Cu deficiency in the field, amenable to control by Cu treatment and genetic selection.
The effect of nutrition on the reproductive performance of first-litter sows 4. The relative effects of energy and protein intakes during lactation on the performance of sows and their piglets
Authors: King R. H. , Dunkin A. C.
Published: September 2010

Eighty-eight first-litter sows were used in a factorial experiment to examine the effects of energy and protein intakes during lactation on subsequent performance. Some received either 45 MJ (E,) or 60 to 63 MJ (E2) digestible energy per day and either 508 to 511 (P,) or 703 to 815 (P2) g crude protein per day during a 28-day lactation.

Sows on the E2P2 treatment lost less body weight during lactation than sows on the other three treatments (P < 0·05). Average live-weight losses during lactation were 21·8, 20·8, 17·8 and 9·6 kg for the E1P1, E1P2, E2P1, and E2P2 sows, respectively. The corresponding reductions in backfat measurements during lactation were 5·5, 7·9, 3·2 and 4·0 mm. Backfat losses were greater for sows given either moderate energy intakes or high protein intakes (P < 0·01).

Neither protein intake nor energy intake during lactation affected subsequent ovulation rate, but piglets sucking sows given high protein intakes grew faster, particularly during the last week of lactation, than piglets sucking sows receiving low protein intakes (P < 0·05).

Within 8 days of weaning, more sows given high intakes of protein during lactation exhibited oestrus than did sows which received lower intakes of protein (27/44 v. 14/44, x2 = 7·7, P < 0·01). Protein intake during lactation affected the nitrogen balance of sows in a similar way. The nitrogen balances were estimated during the 3rd week of lactation, and for sows given rations E1P1, E1P2, E2P1, and E2P2were -20·2, -11·5, -17·5 and -7·2 g/day respectively.
Reproduction in the gilt 6. The effect of various degrees of mature boar contact during rearing on puberty attainment
Authors: Eastham Philippa R. , Dyck G. W. , Cole D. J. A.
Published: September 2010

Abstact

Forty-eight Landrace × (Landrace × Large White) gilts were randomly allocated at 70 days of age to each of three rearing treatments: (1) fence-line contact with a mature boar, (2) olfactory/aural contact with a mature boar, (3) no boar contact. At 160 days of age, all gilts were relocated adjacent to a novel mature boar and exposed to full contact with a mature boar for 30 min each day. At the first, second and third oestrus, 16 gilts from each treatment group were mated twice and the reproductive tracts were examined at slaughter 21 days later, to determine ovulation rate and embryo survival. The rearing treatments had no significant effects on the attainment of puberty. Neither rearing treatment nor oestrus of mating had any significant effect on behaviour, sexual receptivity at first service, conception rate, ovulation rate, the number of embryos and embryo survival at 21 days of pregnancy.