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%.

ANIMAL PRODUCTION, Volume 30, Part 3, pp. 389-394

THE EFFECT OF TRENBOLONE ON ACETATE GROWTH, BLOOD HORMONES AND METABOLITES, AND NITROGEN BALANCE OF BEEF HEIFERS

H. Galbraith

On page 389, title of paper should read:

THE EFFECT OF TRENBOLONE ACETATE ON GROWTH, BLOOD HORMONES AND METABOLITES, AND NITROGEN BALANCE

Animal Production: Volume 12, part 1, pp. 55–62: A number of arithmetical errors have been found in the paper entitled: The incidence, Repeatability and effect on dam performance of twinning in british friesian cattle

An estimate of the frequency of twin calvings was obtained from the analysis of over 38 000 calvings of Friesian cows in M.M.B, milkrecorded herds. The incidence of twinning increased from 0·54% in the first parity to 3·37 % in the fifth parity. A significant excess of cows above expected produced either more than one set of twins or no twins at all. Repeatability ranged from 0·028 for cows with three calvings to 0·063 for cows with five calvings.

Data on lactation yield and duration, butterfat percentage and calving interval showed some significant effects of twinning. Consistent trends were noted showing that dams which calve twins have longer subsequent lactations, higher whole lactation yields and lower fat percentages than contemporary dams with single calves. The possible causes for these trends are discussed and are considered to be the lower breeding efficiency and longer calving intervals of dams of twins.

There has been much recent interest 1n the Duroc as a possible ‘third breed’ in the UK. In particular, claims have been made that meat obtained from Durocs has high eating quality because of raised levels of intramuscular (marbling) fat. In practice, the Duroc 1s likely to be used 1n crosses involving the ‘white’ breeds. Therefore, in this study, carcass and meat quality were examined 1n Duroc, Landrace and Duroc x Landrace pigs produced contemporaneously.

Twenty-one entire males from each of the breed types were used. Landrace pigs were from a long-established Nucleus population of British Landrace. The Durocs were from a selected Nucleus line, originally established from an importation from Canada 1n 1968, expanded and improved by subsequent North American importations and then extensively upgraded by frozen semen from the USA over the period 1980-85 using a wide range of sires. The D x L progeny were produced alongside the purebreds in the Nucleus. All pigs were fed ad libitum on a ration containing 13.8 MJ DE, 200g crude protein and lOg lysine per kg and slaughtered at approximately 80 kg live weight at the IFR abattoir following a standard pre-slaughter procedure.

Major gene-marker phase is generally assumed to be family specific. This has the consequence in relation to marker-assisted selection (MAS) that phase information about each family may need to be collected through progeny testing, which could represent a substantial cost. This paper examines the effect of different policies in relation to major gene-marker phase-typing on response to MAS. The different policies considered varied in the criteria by which individuals were selected for phase-typing, the number of individuals phase-typed, and the frequency of establishing phase. Stochastic simulation of a closed breeding nucleus, with either high or low levels of inbreeding and undergoing selection for two traits, was utilized. Total response under MAS was lower than that under genotypic assisted selection (GAS) for all phase-typing policies. For example, additional gains of 70% under GAS, achieved in year 1 and in comparison with non-MAS, corresponded to additional gains of 43% and 15% under MAS for linkage distances of 1 cM and 20 cM, respectively. The different phase-typing policies examined in relation to MAS did not have any effect on total response, although there were small effects on major gene response. For breeding nuclei with either level of inbreeding, higher major gene response was achieved when phase-typed sires were selected on the basis of high ranking for genetic merit rather than connectivity to the other selection candidates. Further, increasing the number of males phase-typed within any year did not increase the rate of major gene response, although phase-typing in more years was favourable for the large linkage distance. An overall conclusion of this study is that additional gain could be achieved under MAS within a closed nucleus when progeny testing to determine major gene-marker phase was limited to from one to a few individuals.

Testis diameter and body weight were recorded for 37 Finn-Dorset ram lambs born in winter and 38 born in summer 1977 from 8 to 24 weeks of age. Testis growth in summer-born ram lambs reared during a period of decreasing daylength was more rapid than that of winter-born lambs reared during a period of increasing daylength. Hemicastration at 12 weeks of age (19 of the winter-born and 18 of the summer-born lambs) increased the rate of growth of the remaining testis. Season of birth did not affect the response to hemicastration. It was deduced that the feed-back of gonadal hormones on gonadotrophin release was similar in both seasons.

Sixty Large White ♂ × (Large White ♂ × Landrace ♀) pre-pubertal gilts were allocated at random to one of five treatments. Gilts on treatment A were given oestradiol benzoate (OB) at 160 days of age. They were also given allyl-trenbolone (AT) at 166 days of age for 18 days followed by an injection of gonadotrophins (Gn) at 184 days of age. Gilts on treatment B were given OB and AT, but not Gn. Gilts on treatment C were given OB and Gn, but not AT. Gilts on treatment D were given OB only and gilts on treatment E were given Gn only. Gilts which were in heat after 183 days of age were artificially inseminated twice during the first 2 days of oestrus. All gilts were slaughtered either 20 days after insemination or at 220 days of age if they were still anoestrus.

The percentages of gilts ovulating after Gn injection were 36% (4/11), 91·7% (11/12) and 91·7% (11/12) for treatment groups A, C and E respectively (P < 0·01). Gilts on treatments A, C and E were inseminated at a significantly younger age than those on treatments B and D (P < 0·05). No significant differences were found in ovulation rate or embryo survival between treatments.

The results indicated that the administration of AT prior to Gn injection had an adverse effect on both the percentage of gilts ovulating and the development of embryos.

Present Welfare Codes recommend systems of dry sow housing which do not involve close confinement. The ‘Pig-code’ system permits automatic individual rationing of group housed sows without the necessity for individual feeding stalls.

The computer controlled feed station has a gating system enabling it to be used by two separately housed groups of sows. On entering, each sow is identified by its collar mounted responder and given any feed remaining from the preset amount for that time period.

Efficacy of oestrous synchronization and post-treatment fertility was studied in a herd of 149 dairy goats (Swiss breed no. = 104, indigenous Greek breed no. = 45) kept under an extensive farming system. All does were synchronized during the transitional period (during July prior to the breeding season) using fluorogestone acetate (FGA) impregnated intra-vaginal sponges, equine chorionic gonadotropin (eCG) and different prostaglandin F2a (PGF2α) analogues. Four doses of prostaglandin F2a (group 1: 4·5 mg luprostiol; group 2: 2·25 mg luprostiol; group 3: 0·2 mg cloprostenol; group 4: 0·1 mg cloprostenol) were administered i. m. 48 h prior to the end of progestagen treatment and 400 IU eCG was administered at sponge removal. All does were inseminated with fresh semen (300 ✕ 106 spermatozoa per insemination) 42 to 44 h after sponge removal. There were no significant differences (P > 0·05) in the number of goats showing ovarian activity (blood progesterone concentration ³ 1 ng/ml) prior to oestrous synchronization between PGF2α treatment groups. No significant differences (P > 0·05) were observed for the kidding rates between the treatment groups. Our results indicate that goats with ovarian activity prior to sponge application who received high doses of PGF2α showed lower conception rates than those detected in anoestrus (P 0·05). No differences (P 0·05) were observed in conception rates between groups that received lower doses of PGF2α. July is considered to be a transitional period suitable for oestrous synchronization for both Swiss and indigenous dairy goats. Natural mating during the two subsequent cycles after artificial insemination improved kidding rate, but without any significant difference either between treated groups or between Swiss and indigenous breeds.

The plasma concentrations of cortisol and progesterone during reproductive maturation in the heifer calf were examined. Six beef heifer calves were handled and bled every 2 weeks (control), 30 were left unhandled (naive). At 13, 21, 30, 39 and 47 weeks of age, a different group of naive heifers and the control heifers were bled every day for 5 days (puberty seen at 57·4 (s.e. 1·3) weeks). Thirty-nine dairy heifer calves were allocated to seven groups to receive adrenocorticotropic hormone (ACTH) at either 4, 7, 9, 16, 26, 36 or 46 weeks of age (puberty expected around 43 weeks of age). Plasma concentrations of cortisol increased at 21, 30 and 39 weeks of age in frequently handled and naive beef heifers; the increase was greater at these ages in the naive beef heifers (age and treatment P < 0·01). No age trend was apparent for plasma concentrations of cortisol and progesterone prior to ACTH injections (t = 0) in frequently handled dairy heifers. Adrenal progesterone secretion did not change with age in beef heifers, but naive beef heifers had greater plasma concentrations than frequently handled beef heifers. ACTH induced cortisol release in dairy heifers as early as 4 weeks of age (P < 0·05), but the response was greater in dairy heifers 16 weeks old and older (P < 0·05). A progesterone response to ACTH in dairy heifers was not seen until animals were 9 weeks old. It is concluded that as heifers mature reproductively, there is a parallel increase in the sensitivity of the adrenal gland to ACTH and handling stress.

Terminal Sire breeds have a considerable impact on lamb production in Britain’s stratified cross-breeding sheep industry. MLC (1988) estimated that 69% of lambs used for meat production are sired by the Terminal Sire breeds. The predominant Terminal Sire breed is the Suffolk, comprising 46% of the ram population in Britain. The genetic improvement of meat production characters has, traditionally, been difficult in this breed due to the large number of small flocks making up the breed, the restriction on AI use and the lack of a cost/effective central testing facility. However, the formation of the Suffolk Sire-Referencing Scheme Ltd (SSRS), in 1989, has provided a vehicle for faster genetic progress in the breed.

Distillery products which are high in fibre have traditionally been fed only to ruminants, but might provide a cost effective feed for dry sows. If such bulky materials could be fed ad libitum, animal welfare might be enhanced by prolonging feeding time and providing the sows with a greater feeling of satiety in comparison with concentrate diets. To investigate such possibilities, voluntary intake and digestibility were determined with dry sows for three distillery products:

The three distillery products investigated were:

• 1) malt draff (MD), the barley residue remaining after starch extraction

• 2) maize curne gold (CG), evaporated spent wash plus maize cereal residue

• 3) wheat supergrains (SG), centrifuged spent wash plus wheat residue

Each material was offered ad libitum to three pens of 6 dry sows, initially in conjunction with 0.5 kg/sow/day of a balancer meal. The balancer meal contained barley (890 kg/t), limestone (100 kg/t) and a vitamin/trace element supplement at 4 times the normal inclusion rate (10 kg/t). Sows were grouped according to service date and allocated to the experimental treatments in early pregnancy. They were housed in straw bedded pens with individual stalls for feeding of the supplement. Voluntary intake, liveweight and backfat change were monitored over a minimum period of 9 weeks. Sows which failed to maintain acceptable body condition on this regime were given additional ground barley as the experiment progressed.

Silage effluent is a major contributor to farm pollution incidents in the United Kingdom. In 1987, silage effluent was responsible for 26% of all farm pollution cases reported, and 437. Of farm associated water pollution incidents that resulted in prosecution.

A practical solution to this problem could be to incorporate absorbent materials into the grass at ensiling. Several absorbent materials have been tested, some being based on fibrous bi-products. Of those tested, chopped barley straws proved the most effective (Offer an Al-Rwidah 1989) however this material lowered silage quality and also reduced the weight of grass that could be stored in a given silo by 78%. Molassed sugarbeet feed (MSBF), a feed high in digestible fibre which has been widely incorporated into ruminant diets as an energy source, was less absorbent but improved silage quality and reduced grass storage weight for a given silo by only 27%.

A total of 1855 records were analysed using restricted maximum likelihood (REML) techniques to estimate heritabilities separately for males and females lambs on birth weight (BW), weaning weight (WW), 90-day weight (W90) and average daily gains birth to weaning (Cl) and weaning to 90 days (C2). An animal model including fixed effects of year × season, parity, litter size and rearing type; and random effects of direct genetic effect (h2D) and residual was applied. Estimates ofh2Dfor BWwere 048 (males) and 0·50 (females); for WW 0·35 (males) and 0·22 (females); for W90 0·21 (males) and 0·31 (females); for Cl 0·20 (males) and 0·25 (females); and for C2 0·18 (males) and 0·29 (females).

The ability of the gut tissues to absorb nutrients and the extent to which these are then metabolised within the gastrointestinal tract plays a central role in regulating the supply of metabolites to the liver and consequently influences the availability of nutrients for hepatic and peripheral tissue use. Energy consumption by the portal drained viscera is extensive and may account for 25% of total body oxygen consumption (Huntington and Reynolds, 1987). Substrates available for oxidative metabolism include volatile fatty acids (VFA) produced in the rumen and large intestine as addition to arterial supply of these nutrients. The aim of this experiment was to investigate the influence of increased propionate availability on metabolism of VFA in the rumen and the gastrointestinal tract.