Increasing the crude protein (CP) concentration of dairy concentrates in mixed diets has been found to increase milk yield and forage intake in lactating dairy cows. However relatively little is known about the response of lactating goats to such dietary changes. The purpose of the present experiment was to see if beneficial responses could be established in lactating goats given fixed amounts of concentrates with different protein concentrations and ad libitum hay.

Twenty-seven Saanen goats in their second or later lactation were offered 1.5 kg hay (98 g CP, 393 g acid-detergent fibre, 609 g neutral detergent fibe/kg dry matter (DM), and from 0.15 increasing to 0.45 kg concentrates (152 g CP/kg DM) daily in the 6 weeks before kidding. During the first 2 weeks after kidding, the concentrates were increased to 0.7 kg/day. Results for milk production in week 2 were used for covariance in subsequent calculations. At week 3 of lactation all goats were allocated to one of three groups and were offered hay ad libitum and 1 kg concentrates containing 117 (LP), 152 (MP) or 185 (HP) g CP/kg DM daily to week 15.

The current technique for artificial insemination (AI) of ewes during the breeding season necessitates the synchronisation of oestrus with progestagen sponges and PMSG, and involves depositing semen into the posterior cervix at a fixed time after sponge removal. Extensive field trials over a number of years in the UK have indicated that a single insemination using fresh diluted semen 56 h after sponge removal generally results in a conception rate of 70%, while conception rates following a single insemination of frozen-thawed semen 57 h after sponge removal have ranged from 19% to 34% (mean 28%). Giving two inseminations of frozen-thawed semen at 50 h and 60 h after sponge removal increased the overall mean conception rate, but only up to 48%. This inability to achieve acceptable conception rates with frozen-thawed semen nullifies many of the potential benefits of AI in sheep flocks.

It is well established that the cervix presents a major barrier to sperm transport in the ewe, particularly when oestrus has been synchronised with progestagens and PMSG.

Embryo transfer has become a widely used technique for the more rapid dissemination of valuable genetic traits in cattle. The rapid uptake of embryo transfer technology by the cattle breeding industry has largely resulted from the development of non-surgical methods for the recovery of embryos from donor cows and for their subsequent implantation into recipient animals. These non-surgical methods not only reduce operative time but permit the repeated use of cows without the risk of formation of post-operative adhesions.

Although embryo transfer is a technique commonly used by research workers in the study of certain aspects of reproductive physiology in sheep, there are several problems associated with conventional transfer procedures in this species which have precluded its adoption by the sheep breeding industry.

Artificial insemination of ewes has become commercially available in Britain on a small scale over the last few years. It allows the farmer to benefit from MLC recorded rams which have been selected for growth rate and more recently for carcass quality. However, proximity to an A.I. centre is an important consideration as A.I. of ewes requires the use of fresh semen. Frozen semen has not vet achieved the quality and reliability necessary on a commercial scale. Insemination is carried out at a fixed time after the removal of Intra-vaginal pessaries and an injection of Pregnant Mare Serum Gonadotrophin (PMSG). Synchronisation of oestrus using sponges and PMSG adds to the cost of using a commercial A.I. service. If A.I. is not used then one ram per ten ewes is necessary for a synchronised mating which either requires a ram sharing group or considerable financial investment if rams of equivalent quality to those used in A.I. centres are to be purchased.

Immunisation against ovarian steroids has been shown to improve the reproductive performance of ewes. Using this principle the drug Fecundin was developed by Glaxo Animal Health Ltd. and is marketed by Coopers Animal Health Ltd. who supplied the drug for this study. The response to Fecundin was evaluated in ewes lambing in the spring under a wide range of commercial conditions in an ADAS co-ordinated trial.

ADAS Sheep Specialists and Advisers co-operated in locating and collecting the data from suitable commercial flocks and 2 EHF's with a minimum of 150 but more usually 200 ewes and where accurate lambing records could be obtained. Potentially naturally prolific types of ewes eg. Mules and Finn crosses were excluded. Approximately eight weeks before the rams were introduced all the ewes were condition scored and randomised to treatment or control. Treated ewes were injected with Fecundin and again 21-28 days later. At lambing the number of lambs born alive and dead and barren ewes were recorded in all flocks. Lambing dates, lamb birthweights and lamb survival were available in a limited number of flocks.

To investigate the suitability of using high levels of British (high glucosinolate) rapeseed meal (RSM), 80 adult Suffolk-Mule ewes of mean live-weight 64.8 kg (s.e. 0.5) were divided into four balanced groups. Three of the groups were allocated to a concentrate diet containing 20% RSM as the major protein supplement: extracted (B), expeller (C) and extruded (D). The control group (A) was given a diet containing 16.5% soyabean meal (SBM) as the only protein supplement. The remainder of these pelleted diets consisted of barley, molassine meal, oat husks, minerals and vitamins. All four diets contained similar levels of protein and energy.

The ewes were fed 0.7 kg/day during maintenance, 1 kg/day durino mating and increasing amounts from late pregnancy up to a maximum of 2.5 kg/day during lactation. Barley straw was available ad libitum. The ewes were weighed twice monthly. Jugular blood samples were taken monthly for thyroxine (T4) and thiocyanate (-SCN) analyses of plasma, also every five days during mating and the first two months of pregnancy for profiles of progesterone in plasma. The ewes were exposed to raddled entire rams for six weeks during November and December.

Apart from the kale crop, there is no information on the amounts of nutrients absorbed from lambs ingesting forage brassica crops. In particular, knowledge of the amounts of OM apparently digested in the rumen and of the non-ammonia N (NAN) flows at the abomasum are important in predicting the amount of nutrients absorbed and consequently carcase gains. One experiment was conducted using the leaf components of rape and hybrid turnip to describe nutrient supply and to identify whether carcase gains would be limited by the supply of energy substrates or protein to the tissues. A second experiment was conducted with lambs grazing the leaf of both crops and given supplements to test the hypothesis that carcase gains were limited by the supply of energy substrates.

The growth rate and body composition of lambs depend on their rate of feed intake and the composition of the feed given. The purpose of the experiment described here was to test predictions of the growth and composition of lambs given feeds of two protein contents at three levels of feeding.

73 Scottish Blackface wethers were abruptly weaned at 49 days of age and an average live weight (LW) of 18 (sd 2.2) kg. Six, chosen to cover the range in initial liveweight, were killed and those remaining were put into individual pens and fed in one of six ways. Two feeds with 140g CP/kg fresh weight (FW), called LP, and 220 g CP/kg FW, called HP, were used. They were formulated using barley, maize and soyabean meal, and hay at 150g/kg FW, and were calculated to yield 11.8 MJ ME/kg FW. Each feed was given ad libitum (AL) and at daily rates of 1.2 or 0.8 kg FW. The numbers of sheepstarted were: ALHP, n = 8; ALLP, n = 8; 1.2 HP, n = 12, 1.2 LP, n = 13, 0.8 HP, n = 14, 0.8 LP, n = 12. Sheep were killed from each treatment at 5 kg LW intervals from 25 to 50 kg. After slaughter the weights of gut-fill and organs were taken and the carcase physically dissected into lean, bone and fat. The chemical composition - dry matter and the ash, N, lipid and gross energy contents of the dry matter - of the whole empty body, excluding wool, was measured. Wool weights were determined. The intakes and weights of each sheep were measured twice weekly.

The experiment described here was designed to test the proposition that lambs, given access to two feeds, as a choice, one abundant in crude protein (CP), the other deficient, can both select a diet which supports their potential growth rate and which avoids excesses of protein intake.

Twenty four Suffolk x Greyface wether and females, at a mean liveweight of 20.2 kg (s.e. 0.6) were individually housed and their feed intake and liveweight recorded weekly.

The four pelleted feeds used were highly digestible and had estimated energy yields of 10.5 MJ ME/kg freshweight. The basal feed (A) was made from equal parts barley and sugar beet pulp plus a vitamin/mineral mix. It contained 91 g CP/kg FW. Feed D was made by substituting fishmeal for the barley in feed A such that it contained 383g CP/kg. Feed B contained one third D and two thirds A and contained 182g CP/kg. Féed C contained two thirds D and one third A, giving a CP content of 266g CP/kg. Thus each of the four feeds A, B, C and D could be described in terms of either the proportion of feed A or the crude protein which it contained.

Four lambs were offered feed A alone, and four lambs received feed B only. Twelve of the lambs were given ad 1ibitum access to both the basal feed A and one of the three other feeds B, C and D, for ten weeks. Four lambs were offered a choice between feed B and feed D for four weeks.

As the performance of store lambs on silage alone is often disappointing and feeding cereals reduces margins considerably, supplementing with fish meal offered an economic alternative for investigation.

The aim of the system was to finish lambs indoors (gaining 8 - 10 kg over 3-4 months ie 90 g/day DLWG) on a mainly forage diet to achieve a gross margin of at least £5 per lamb.

80 Suffolk x Scotch halfbred store lambs (AV 35 kg) were offered good quality precision chop grass silage at grass for three weeks. They were then divided into Control (C) and Treatment (T) groups at housing in mid November.

A number of mechanical methods are available for the diagnosis of pregnancy and the determination of foetal numbers in sheep. The application of four ultrasonic systems currently used commercially was investigated.

The ‘scanning window’ in the ewe is apparent between approximately 45 to 100 days of pregnancy. Highly accurate pregnancy diagnosis and prediction of foetal numbers have been reported using the real time scanning technique. However, considerable variation in expertise can exist between operators while further discrepancies emanate from the different methods used to calculate predicted success rates. The estimation of operator accuracy from trial work is complex since errors may arise from both over- and under-estimation of foetal numbers resulting in confusion when pregnant ewes are subsequently grouped incorrectly. A true estimate of operator accuracy should reflect relative foetal numbers predicted.

Increased food intake of ewes has been noted at experimental and research centres as a consequence of shearing in mid-pregnancy (Great House EHF, 1972/3, Drayton EHF, 1976, 1977, Grassland Research Institute 1976). This should allow a greater reliance on cheaper home-grown forage to supply nutrients during the latter stages of pregnancy. Silage alone or with small amounts of energy and/or protein supplementary feed, may provide the nutrients to support shorn in-lamb ewes through to lambing.

One hundred and four shorn Border Leicester x Welsh Mountain ewes, penned in groups of 26, were offered silage ad libitum from housing in mid-January until lambing in early April. Six weeks before lambing, supplements were introduced. The treatments were either no supplement (Nil), rolled barley (B), white fishmeal (FM) or rolled barley plus white fishmeal (B + FM).

Although there are numerous reports on the influence of dietary fats on milk yield and milk composition in the dairy cow (see review by Palmquist, 1984) little is known about the value of fat supplements in the diet of lactating ewes, a species which produces milk of a much higher fat content than the dairy cow. We now report the results of three experiments in which lactating ewes received diets supplemented with a lipid source that was protected from hydrolysis in the rumen.

Individually-penned Finnish Landrace x Dorset Horn ewes, each suckling two lambs by Suffolk rams were used in all three experiments. They were given a diet containing (per kg): 500 g hay (milled through a 4 cm screen), 300 g barley, 90 g white fish meal, 5 g dicalcium phosphate, 3 g salt and 2 g of a trace mineral/vitamin supplement. The crude protein and metabolizable energy contents per kg dry matter were 145 g and 10 MJ respectively. The source of the protected lipid was calcium palmitate (Megalac, Volac Ltd) with lipid and calcium contents (g/kg) of 850 and 90 g respectively.

Previous work on winter shearing has concentrated on lowland ewes in mild conditions. With increased emphasis in hill areas on housing ewes before lambing and resting hill pastures, the possibility of shearing ewes before lambing, rather than in the summer now exists. A review of work with lowland ewes has shown that winter shorn ewes produce lambs with a heavier birthweight (average +0.55kg) and increased liveweight gain (average +15g day-1) (Phillips, 1980), but it is not clear whether these benefits would be obtained with less prolific ewes under hill conditions.

The experiment was carried out from February to July 1985. Twenty-two Welsh Mountain ewes were housed 45 days pre-lambing in a fully enclosed but well-ventilated shed with slatted flooring. At 42 days pre-lambing ewes were randomised for weight and age and half the ewes were shorn with a normal comb, and half left unshorn until the summer.

Ewes in both treatments were offered and consumed the same level of concentrates (0.25kg ewe-1 day-1 post-shearing increased to 0.5kg ewe-1 day-1 before lambing). Medium quality hay was offered ad-libitum to both treatments. Water intake was measured daily. Ewe liveweight was measured weekly on five occasions between shearing and one week before lambing. Respiration rates of ewes were measured on 4 different occasions at 4 extreme environmental temperatures. Maximum and minimum house temperatures were recorded for the whole of the housed period. Lamb birthweights, liveweight gains and 84 day weights were corrected to male singles using additive correction factors derived from the mean of the flock over the previous two years.

An experiment was carried out at the Glensaugh research station to investigate the effects of breeds of ewe, differing in mature body size on the utilisation of a long-established reseed maintained at sward heights of 3.5 and S.5 cm until weaning.

The experimental area, dominated by Lolium perenne (40%), Poa spp (30%) with other grasses (10%) and weed species (20%), was divided into 12 plots each of 0.7 ha. When the mean sward height reached at least 3.5 cm in every plot (13.5.85) they were each stocked with 9 ewes + 15 lambs from one of 3 ewe genotypes (Border Leicester x Blackface, GF; East Friesland x Blackface, EFX; Cheviot x Shetland, SHX) in two replicates. All lambs were sired by Suffolk rams.

Mean sward height, herbage mass and estimated herbage accumulation rate were measured weekly and ewes and lambs were weighed weekly. Sward heights were maintained on each plot by movement of an electric fence to vary the grazing area. The area behind the fence was maintained at an equal sward height by non-experimental ewes and lambs to permit movement in any direction. The lambs were approximately 6 weeks old at the beginning of the trial and were weaned after 13 weeks on the plots.

The effect of contrasting white clover contents on diet selection by grazing sheep provides an insight into grazing behaviour mechanisms. When sheep have a choice between ‘strips’ containing either 70% white clover or 100% grass they consistently choose to graze the former. When clover is intermingled with grass in normal sheep-grazed swards evidence for selective grazing is less clear. The objectives of this experiment were, firstly, to define the pattern of discrimination in response to variation in the contrast in clover content between alternative swards. And, secondly, to test whether the pattern is affected by the mean clover content about which the range is established.

The ‘base’ levels of clover content: 30 and 60% together with 7 ‘contrast’ levels from -30 to +30% of ‘base’ level were planned. Swards of equal content were included as controls. Thus the 30% base was contrasted with 0, 10, 20, 30, 40, 50 and 60%; and the 60% base with 30, 40, 50, 60, 70, 80 and 90% white clover. Each combination of treatments was repeated at two nitrogen levels: C and 30 kg N/ha and the whole replicated twice. The experimental area was at Grasslands Division, Palmerston North, New Zealand. The pasture comprised well-established Ruanui ryegrass - Huia white clover with some weed species. Fifty-six plots (5.6 x 3.5 m), each containing 2 ‘contrast’ areas at 2.8 x 3.5 m were sprayed with different herbicides on 29 July 1983 to achieve the above contrasts.

Previous work has shown that a sward height of 3-5 cm for sheep is the most efficient way of maintaining a balance between new .growth and decayed material. An unreplicated experiment was carrried out during 1985 using 77 cross-bred ewes and their Suffolk x twin lambs to graze a perennial ryegrass sward (Lolium perenne) cv Wendy between 29 April and 22 July (weaning). Animal performance was monitored and grazing behaviour noted. Sward height measurments were taken twice weekly with an HFRO sward stick on a 0.4 ha plot (P) and on the remaining 5.8 ha field (F). Grazing commenced on each area when the sward height reached 4 cm ± 1 and was maintained at this height on P by adjusting animal numbers. Physical data was recorded from a minimum core flock of 5 ewes and 10 lambs. Area F was set stocked at 12.4 ewes/ha. Areas F and P received 198 kg N/ha in total, applied at monthly intervals between early April and July. Net herbage accumulation was recorded at 21 day intervals under exclusion cages on each area.

Silage aftermaths have been used to reduce the stocking rate of the flock in mid season when the lambs are eating more grass. When straw is fed as the only source of roughage to housed pregnant ewes, aftermaths are not available so different grazing management may be required.

1. 1. 29 ewes and their lambs grazed initially at 22 ewes/ha reducing to 15 ewes/ha when aftermaths become available (control).

2. 2. 29 ewes and their lambs grazed 8t 22 ewes/ha set stocked through the grazing season.

3. 3. 29 ewes and their lambs grazed at 22 ewes/ha set stocked throughout the grazing season and creep feed offered to the lambs.

4. 4. 29 ewes and their lambs grazed at 22 ewes/ha set stocked throughout the grazing and ammonia treated ’ barley straw offered to the ewes and lambs.

Two days after lambing in mid March, the ewes and lambs were turned onto their plots. Each treatment consisted of 22 ewes with twin lambs and 7 ewes with single lambs. Concentrates were fed to the ewes at grass until April 30. On 4 June 1984 the stocking rate for treatment 1 was reduced to 15 ewes/ha when silage aftermaths became available. The grazing area of all treatments received 125 kg/ha N in 3 equal applications during the grazing season.

The n-alkanes of grass outioular wax (odd-chain, C25- C25) can be used simultaneously with dosed n-alkanes (C28or C32) as markers for estimating the herbage intake of grazing sheep if the faecal recoveries of both herbage and dosed markers are the same. In adult sheep the accuracy of herbage intake estimation is not affected by the inclusion of concentrate in the diet as long as the intake and alkane concentrations of the concentrate are known. If, similarly, the ingestion of milk does not interfere with the relative absorption of dosed and herbage alkanes the herbage intake of suckling lambs at pasture could be estimated. To evaluate the potential of the technique in suckling lambs the faecal recoveries of odd-chain herbage n-alkanes and of dosed dotriacontane (C32) were determined in lambs offered eves’ milk and freshly cut herbage.

From 2 weeks of age seven individually-housed male lambs received 1 kg/day homogenised ewes’ milk (166 g/day dry matter (DM)) in 4 feeds from an automatic feeder. The milk Has obtained by daily hand-milking of East Friesland ewes and was stored at -20° until used. Freshly cut perennial ryegrass was offered to the lambs ad libitum from the age of 4 weeks. A 6-day total collection of faeces was carried out when the lamba were 10 weeks of age.

Studies with sheep suggest that accurate estimates of herbage intake can be obtained by using the herbage alkane tritriacontane (C33) and dosed dotriacontane (C32) as markers, since the faecal recoveries of both alkanes have been shown to be very similar. To validate the technique for herbage intake estimation in grazing cattle there is a need to compare in cattle, the faecal recoveries of both herbage and dosed n-alkanes. It has been observed in sheep that the faecal recoveries of n-alkanes increase as their chain lengths increase, suggesting that the recovery of hexatriacontane (C36), an alkane absent from herbage but available commercially at low cost, should be complete. C36 may therefore have potential as a dosed marker for estimation of faecal output. Thus it may .30 be possible to obtain estimates of both herbage intake and diet digestibility in the same individual grazing animal using n-alkanes as markers. The purpose of the experiment described here was to determine the faecal recoveries in cattle of odd-chain n-alkanes from fresh herbage and of C32 and C36 dosed n-alkanes.