Sheep Research at Lyons Farm

Lyons Farm as a long history of conducting and disseminating research relating to sheep production. The Lyons flock consists of 360 breeding females managed in a  mid-season lambing system. The flock comprises of three main breed types, Belclare, Lleyn and Mule each selected for their high prolificacy. Ewes are mated each October following an oestrus synchronisation program to Charollais and Vendeen rams. Traditionally ewes are housed in mid-to-late December and lamb indoors in mid-March. Following lambing ewes and lambs are turned out to pasture where the objective is to finish the majority of lambs on an all forage diet. Lambs are weaned in the third week of June. Forage crops such as Redstart are established following the harvest of winter cereals to finish lambs in the September to December period.

Research Areas

The sheep flock has recently supported and currently supports a number of major national research projects. The overall objective of the research conducted at Lyons is to enhance the sustainability of sheep production systems through a number of approaches as follows

1. Reducing lamb mortality through a better understanding of colostrum production and quality and the    transfer of antibodies to the newborn lamb.

2. Maximising milk production and lamb growth rates

3. Identifying novel phenotypes to improve national breeding programs

Other Research Projects Include

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Overview:

Tommy Boland, Connie Grace, Bridget Lynch and Helen Sheridan

The ability to grow large quantities of high quality grass at a low cost relative to other feed resources is often and correctly cited as an important competitive advantage for Irish livestock producers. As 2017 is the ‘Year of Sustainable Grassland’ it is appropriate that results arising from a large scale project funded by the department of Agriculture, Food and the Marine involving researchers in UCD, Teagasc and AFBI indicate how pasture based production can be enhanced in terms is its sustainability. 

The SMARTGRASS project has focussed on dry matter yield, forage quality, ensiling potential, animal production, impact on associated biodiversity and soil structure from a range of sward types including perennial ryegrass monocultures right up to ‘multispecies’ mixtures containing nine separate species encompassing grasses, legumes and herbs. Many of these herbs in particular are found in older pastures, but the varieties under investigation in SMARTGRASS are agronomically improved varieties, more suited to the rigours of modern day livestock farming.

A number of experimental approaches were taken in the SMARTGRASS project, including traditional plot scale studies, actual versus simulated grazing studies, systems grazing studies and ensilability studies. 

For the plot based studies 100’s of plots were established encompassing a wide range of mixtures incorporating different proportions of nine species (perennial ryegrass, timothy, cocksfoot, red clover, white clover greater birdsfoot trefoil, ribwort plantain, chicory and yarrow). These plots were harvested under an eight cut simulated grazing protocol across three harvest seasons. Key findings arising from this portion of the study include: multispecies sward mixtures, had higher yields of DM per ha compared to monocultures over three years, even though the multispecies swards received considerably lower nitrogen inputs (90 kg versus 250 kg N per ha per year). The yield achieved in the multispecies swards was more persistent over the three years compared to the high input monocultures. Additionally the multispecies swards were more resistant to weed invasion over the course of the study. 

Following on from this the comparison of multispecies swards to monocultures under both actual (animal) grazing and simulated (machine mowing) grazing showed that great care is needed when assessing the performance of multispecies swards. While the performance of the perennial ryegrass monocultures were similar under both assessment methods, the multispecies swards had lower yields under the actual animal grazing methodology. In some ways this is not surprising as the cutting and grazing protocols were both designed for perennial ryegrass, and we know the swards containing a range of species require somewhat different management. 

A third major study involved the establishment of a large animal grazing systems study at Lyons Farm to test how animals performed when offered four sward types over two grazing seasons. Swards were established in September 2014 and were grazed in 2015 and 2016. The swards tested were a perennial ryegrass only sward (PRG) receiving 163 kg N/ha/yr; a perennial ryegrass plus white clover sward (PRGWC) receiving 90 kg N/ha/yr; a six species sward (6S) containing perennial ryegrass and timothy, white clover and red clover, ribwort plantain and chicory receiving 90kg N/ha/yr; and a nine species sward (9S) including the six species above plus cocksfoot, greater birdsfoot trefoil and yarrow receiving 90 kg N/ha/yr. Each sward type was managed as a separate farmlet, with 5 grazing divisions per farmlet and operated under a rotational grazing system stocked with 12.5 twin rearing ewes per hectare. 

Findings show that lambs grazing the multispecies swards had higher growth weights to weaning than lambs grazing perennial ryegrass only. Lambs from the 6S swards had a weaning weight of 33.3kg at 14 weeks of age, and this was 2.5 kg heavier than the lambs grazing PRG. These lambs grazing the 6S grew at a rate of 350 grams per day from birth to six weeks of age. Indeed lambs on all sward types had growth rates in excess of 300 grams per day for the first six weeks of life, and by including additional species to perennial ryegrass in the sward lamb performance was improved. 

As the lamb is dependent on the mother’s milk for essential all its energy requirements at this stage of life, this suggest that these ewes either produced more milk, or the milk they produced had a higher content of solids (fat and protein). 

Further key findings from this study include the reduced requirement for dosing to control stomach worms when lambs were grazing swards containing herbs (chicory and plantain). This is potentially a very important finding for Irish sheep farmers. One of the key challenges in pasture based production systems is the need to control intestinal parasites such as stomach worms. This control has largely depended on the use of chemical anthelmintic, though recent evidence shows there is huge resistance within the parasites to these drugs. The fact that animals grazing multispecies swards required less dosing, is critical as it points to a lower reliance on these drugs to control these parasites, as there are some anthelmintic properties within the plants themselves. 

Finally, the lambs grazing the multispecies swards were slaughtered at a younger age (same weight) than the lambs grazing the perennial ryegrass only sward. This frees up grass at a key time on sheep farms in the pre mating season for flushing ewes, ensuring correcting body condition score at mating and supporting a good litter size within the flock. 

On the environmental side a number of key benefits are also evident. More species rich swards support greater invertebrate biodiversity, with earthworm numbers and diversity increased in multispecies swards. Also some modelling data would suggest the potential to reduce nitrous oxide emissions per kg of ‘grass’ DM produced when using multispecies swards, largely arising from the reduced fertiliser N requirements. 

There are some issues to consider however, these include the issue of dealing with weeds in newly established swards, and the persistency of the swards over time. Weed encroachment is an issue as there are no chemical herbicides available in Ireland that would not remove either the herbs or the grass from the sward when controlling weeds. Interestingly though the multispecies swards were more resistant to weed encroachment compared to perennial ryegrass monocultures where no weed spray was applied. 

Further work is required to develop management blueprints for the incorporation of multispecies swards in to grass based production systems but there is enough evidence here to support further investigation.

 

 

Overview:

Sheep production is an important agricultural sector to the Irish exchequer, with an export value of €275 million in 2017 (Bord Bia, 2018). The current Irish national sheep flock comprises of 2.6 million breeding ewes across approximately 36,000 flocks (DAFM, 2017) split across two main production systems: lowland (75%) and hill (25%) (Teagasc, 2013). The national average flock size (107 ewes; DAFM, 2016) remains small relative to international competitors, thereby requiring constant focus on increasing efficiency in order to ensure profitability. Stocking rate and ewe prolificacy potential are key drivers of profitability. An increase in weaning rate from 1.5 to 1.8 lambs per ewe increases profitability by €440 per ha (Bohan et al., 2018) where increased lamb output is supported by enhanced grass growth and utilisation due to lower relative costs of grazed grass (Finneran et al., 2010).

While Irish sheep production systems are pasture based, recent survey data show that 40% of farmers offer concentrate supplementation to ewes in early lactation and only 9% of survey respondents never supplement lambs with concentrates (Bohan, 2017). As a result purchased concentrates are the single largest contributor (~40%) to direct costs on sheep farms (Teagasc, 2017). However Campion et al. (2017) reported that concentrate supplementation in early lactation offered no animal performance benefit and served only to reduce grass dry matter intake, while Earle et al. (2017) showed that as much as 90% of all lambs can be finished from pasture alone. Furthermore animal performance at pasture can be enhanced by offering multispecies swards with concomitant reductions in fertiliser inputs and anthelmintic utilisation (Grace et al., 2018). Significant scope exists to increase the output and profitability of the Irish national sheep flock through increasing prolificacy and maximising the contribution of forage to the diet of the animal. 

UCD Lyons farm has just completed the first lambing season of a new five year project comparing three breed types selected for prolificacy, namely Mule, Lleyn and Belclare.  It is too early to begin to draw any messages from the data as to which breed type is performing best but valuable data is being collected. Table 1 shows litter size, mortality rate, lamb birth weight, lambing difficulty and ewe mother ability across litter size. 

Table 1. The effect of litter size on mortality rate, lamb birth weight, lambing difficulty and ewe mothering ability

Litter size

Lambs born

 

Lambing

Difficulty*

Mothering ability*

Lamb birth weight

 

Alive

Dead

Total

Mortality (%)

Average

1.97

0.19

2.16

9

2.01

1.16

4.72

Single

0.96

0.05

1.00

4

1.74

1.21

5.65

Twin

1.86

0.14

2.00

7

1.99

1.13

5.08

Triplet

2.73

0.27

3.00

9

2.15

1.17

4.30

Quads/quins

3.15

0.85

4.00

21

2.65

1.32

3.85

 * Scored on a scale of 1 to 4 with 1 being best and 4 being worst for the traits measured

An examination of the average flock performance points to an overall high level of performance, given the fact that approximately 60% of the flock comprises ewe lambs and hoggets lambing for the first time. When we delve a little deeper into the data, we note some interesting, although not completely unexpected differences appearing. Mortality increases with litter size, and although overall mortality at 9% is in line with targets for the given litter size, mortality increases dramatically for ewes given birth to four or more lambs. This is partially explained by the low numbers of ewes in this category (just 20 out of 280) plus the fact that two of these ewes delivered four dead lambs each which had been dead for some time in utero. Nevertheless detailed measurement of this over the years will be important as potentially important welfare issues arise if this trend continues. 

This year we also recorded mothering ability will dis-improve with increasing litter size, with the exception that ewes giving birth to singles had a poorer mothering ability score than ewes producing twins or triplets. However I believe this is a reflection of the fact that many of the sheep producing singles were first time-lambers and indeed ewe lambs, and is an artefact of the unusual flock structure we have this year. I would not expect this trend to continue over time. The other question it raises is, do ewes who give birth to large litter sizes have poorer mothering ability (one would certainly hope this is not the case) or is this a very temporary response we are seeing, perhaps associated with the stress of multiple births. Mothering ability in this case was measured as the ewe’s inclination to follow the lambs as they are being carried from the group pen to the individual pen.

This research is at a very early stage and much more detailed information will be collected as this year and subsequent years progress. Where farmers are interested in increasing litter size, through the use of one of the breed types included in this study it is important to assess the potential impact of breed type choice on performance, labour requirement and overall profitability, all of which will be measured in this project.

Overview:

Late gestation and early lactation are key periods in the ewes production cycle during which nutrient requirements are highest and intake potential is limited. Rationing ewes using an metabolisible Energy (ME) system led to lower energy intakes during the final five weeks of gestation compared to ewes rationed on a net energy (NE) rationing system.

  • Ewe colostrum production to 18 hours post-partum was unaffected by late gestation energy rationing system used but is influenced by ewe breed, ewe age, gestation length, lamb birth weight and ewe live weight change.
  • IgG yield was also influenced by ewe breed, ewe age, gestation length and lamb birth weight.
  • Grass dry matter intake was reduced between weeks two and seven of lactation when ewes were offered concentrate supplementation in comparison to ewes receiving ad libitum grass only but there were no concurrent improvements in total dry matter intake as a result.
  • Concentrate supplementation did not improve ewe milk production or progeny growth rates to six weeks post-partum  in comparison to ewes receiving an ad libitum grass only diet.
  • Increasing NE allocation above 100% of recommendation during late gestation altered body reserve mobilisation pattern during late gestation and early lactation.
  • Change in Body Condition Scoring (BCS) from mating to weaning is influenced by flock, year, ewe breed, progeny breed, ewe age, litter size at parturition and mating BCS. The change in ewe BCS and how it affects flock performance is influenced by ewe breed type.
Accurate management of late gestation and early lactation ewe nutrition is vital to improving flock performance and output.
In order to accurately manage flock nutrition it is important to understand how factors outside of nutrient intake such as ewe breed and age affect performance parameters such colostrum production and body reserve mobisation

Research by Dr. Francis Campion

 

Overview:

Late gestation maternal nutrition is a key contributor to animal performance and profitability on sheep farms. The aim of this study was to increase knowledge of the impact of late gestation maternal nutrition on foetal development and the performance of both dam and offspring in the post-partum period.

Two approaches were taken, namely examining the ewes’ response to altered levels of metabolisable energy (ME) supply and the mechanisms underpinning the failure of passive transfer (FPT) in the newborn lamb following excess maternal iodine (I) supplementation.

Restricting the quantity of ME offered to the ewe (80% ME) reduced ewe live-weight and body condition score at 24 h post-partum, total colostrum yield to 18 h and estimated milk yield on week 3 of lactation. The impact of the ME restriction wasn’t reflected in individual lamb organ or birth weights, however a decline in weaning weight and growth rate to weaning were observed; indicating that lamb birth weight can be a poor predictor of post-partum performance.

Excess I induced FPT which is mediated through a decrease in Tconcentration and a downregulation of THRBin the ileum of the lamb. Excess I supplementation downregulated B2Mand ALBin the neonatal ileum at 24 h post-partum. Furthermore, the villus height and the villus height to crypt depth ratio in the lamb was negatively affected, while lower concentrations of serum IgG were observed to 28d post-partum. Lambs born to I supplemented dams had higher growth rates to weaning and lower faecal egg count for Nematodirus battusfrom 42-70d post-partum. 

Accurate nutritional management of the ewe for the final four weeks of gestation is therefore vital due to the affects imposed on both ewe and lamb performance post-partum.

Research by: Dr. Fiona McGovern

Overview:

The objectives of this study were

1. To investigate the effects of herbage type and concentrate supplementation on diet digestibility, rumen fermentation parameters and methane (CH4) mitigation in the rumen simulation technique (RUSITEC).

The herbage types evaluated consisted of

    • perennial ryegrass (PRG),
    • PRG and white clover (WC),
    • a 6 species mix containing two grasses, two legumes and two herbs
    • a 9 species mix containing 3 grasses, 3 legumes and 3 herbs.

The herbage treatments were incubated in RUSITEC as herbage only or supplemented with a by-product concentrate consisting of soya hulls (SH), palm kernel meal (PKM) and maize distillers grains (MD), with added linseed oil (LO). The herbage and concentrate treatments were incubated in 60:40, forage:concentrate ratio.

Results

The 9 species herbage treatment was highest in terms of diet digestibility, while PRG produced significantly lower ammonia (NH3) levels than any other treatment. In terms of CHproduction PRG/WC and the 6 species mix were lowest, while PRG and the 9 species mix produced significantly higher CHlevels.

When concentrate was supplemented to herbage treatments digestibility values and NH3production was lower across all treatments, while total VFA and CHproduction were reduced in three of the four treatments.

2. To ubderstand the effects of Linseed Oil (LO) supplementation pre- and post-weaning on feed conversion efficiency, carcass evaluation and rumen function in intensively finished lambs.

Ewes and lambs were fed a grass silage based diet pre-weaning containing one of two concentrates types (with (L) LO or without (C) LO). After weaning lambs were placed in one of four treatment groups:

    • C = concentrate without LO fed both before and after weaning,
    • L = concentrate containing LO fed both before and after weaning,
    • C-L = concentrate without LO fed before weaning and concentrate containing LO fed after weaning,
    • L-C = concentrate with LO fed before weaning and concentrate without LO fed after weaning.

Results

Pre-weaning LO supplementation had no effect on animal performance, while post-weaning LO supplementation increased carcass weight and kill out percentage compared to the control diet. The proportions of propionic acids and butyric acid in total VFA production were altered with LO supplementation, which suggests a programming effect on the rumen microbial population with pre-weaning supplementation. In conclusion LO supplementation in ruminant diets has been shown to mitigate CHproduction and reduce NH3production in RUSITEC, while post-weaning LO supplementation increased lamb performance in the finishing period. 

Research by: Mark Boland

 

Overview:

This research examined the effect of reduced metabolisable energy (ME) intakes during late gestation with concurrent changes in other dietary nutrients on ewe and subsequent lamb performance. It also examined the impact on performance when ewes are fed according the ME system or a net energy (NE) system.  

The impact of offering ewes 90% vs. 100% of their ME requirement during the final month of gestation had no effect (> 0.05) on ewe liveweight, body condition score (BCS), litter weight, colostrum yield or composition, or colostrum intake per kg of birth weight. It did increase (P< 0.05) gestation length for ewes offered the 90% ME diet but had no effect (> 0.05) on average daily gain of the progeny or any carcass characteristics. Ewes offered the 100% ME diet had higher crude protein and dry matter intakes (P< 0.05).

The impact of offering ewes 80%, 90% and 100% of their recommended ME intakes during late gestation, and a comparison of offering ewes 100% ME and 100% NE were also assessed.  Ewes offered 80% ME lost more (P< 0.05) body weight, had the lowest (P< 0.05) concentrations of betahydroxy butyrate, and greatest (P< 0.05) concentrations of non-esterified fatty acids during late gestation, however they lost the least (P < 0.05) liveweight during lactation compared to ewes offered 100% ME. The 80% ME ewes also had the greatest (P< 0.05) lambing difficulty compared to the 100% ME diet. Treatment tended (= 0.14) to effect days to slaughter, with lambs from the 100% NE ewes taking approximately 23 days longer than their 100% ME counterparts. Treatment had no effect (> 0.05) on any carcass characteristics.

Research by: Kevin McDermott