Developing tools to restore fertility in dairy cows
Submitting InstitutionUniversity of Nottingham
Unit of AssessmentAgriculture, Veterinary and Food Science
Summary Impact TypeTechnological
Research Subject Area(s)
Engineering: Food Sciences
Medical and Health Sciences: Paediatrics and Reproductive Medicine
Summary of the impact
Fertility of dairy cows has been in decline since the 1970's and this has
threatened sustainability of the dairy industry worldwide. Research led by
Nottingham University (UoN) identified key drivers of fertility and
provided genetic and nutritional tools for the industry, to help combat
the decline. The genetic tool was the UK Fertility Index, which is used
universally by breeders for national and international bull selection. The
nutritional tool, which is widely applied by international feed companies,
used the concept that nutritional manipulation of insulin enhances
fertility. Evidence shows that use of these tools between 2008 and 2013
has reversed the decline, and fertility is being restored. This has
brought commercial benefits for breeding companies, cattle food producers
and farmers and had a positive impact upon animal welfare.
Professor Tony Flint, Prof of Animal Physiology (UoN 1993-2009), PI for
Professor Phil Garnsworthy, Prof of Dairy Science (UoN 1980-present), PI
for nutritional research.
Professor Bob Webb, Prof of Animal Science (UoN 1997-2012), PI for
reproductive physiology research.
Professor Kevin Sinclair, Prof of Developmental Biology (UoN
2003-present), reproductive physiology.
Dr George Mann, Associate Prof (UoN 2003-present), reproductive
In collaboration with the Roslin Institute (D. Armstrong, J. Gong, J
Woolliams), Scottish Agricultural College (SAC) Aberdeen (K. Sinclair
until 2003, then J. Rooke) and SAC Edinburgh (E. Wall, M. Coffey).
Nottingham has a long history of world-leading research in bovine
reproduction and pioneered the use of milk progesterone to monitor
fertility of dairy cows. By comparing progesterone data in the 1990s and
1970s [a] UoN revealed a significant decline in fertility among UK
dairy cows, which was negatively associated with genetic merit for milk
yield . Similar trends have since been identified in most
countries with well-developed dairy industries. Cows exhibited delayed
ovulation and conception rate was declining by 1% per annum. Poor
fertility was estimated to cost the UK dairy industry £350 million per
annum, mostly through premature culling of healthy cows that failed to
conceive. With strategic funding from Defra and industry, a collaborative
research programme, led by Nottingham, was started in 2000 to find ways to
restore fertility through genetics and nutrition, the two main drivers of
In the genetic work [b], UoN established genetic characteristics
of dairy cow fertility traits derived from milk progesterone data, which
were combined with heritability of management measures of fertility
obtained at SAC . In a Nottingham-led follow-up programme [c]
approximately 1.4 million daughter records from 18,000 sires were used to
generate a Fertility Index for bulls. The Index was based on daughters'
calving interval, insemination data, pregnancy rate, milk yield and body
condition score. An Index value was calculated for each bull so that bulls
could be ranked for selection purposes .
In the nutrition work [d-g], it was noted that, cows with high
genetic merit for milk yield had lower plasma insulin concentrations than
average cows and hypothesised that nutritional manipulation of insulin
might enhance fertility. A pilot study demonstrated that, a diet that
stimulated insulin secretion increased the proportion of cows ovulating in
the first 50 days postpartum . In subsequent studies with 23
dietary treatments, equations were developed to predict effects of
nutrition on insulin and fertility . Parallel studies explored
physiological mechanisms at the ovarian and systemic levels to explain
whole-animal responses. The novel observation was made that although diets
that induced higher insulin concentrations stimulated ovarian follicles ,
high insulin was detrimental to oocyte quality . A key insight
was that reproductive performance of dairy cows might be improved by
differential nutrition at different phases of the reproductive cycle. It
was demonstrated that feeding a diet designed to stimulate insulin during
the early postpartum period and then a diet designed to lower insulin
during the mating period increased the proportion of cows pregnant at 120
days of lactation from 27% in control treatments to 60% in the optimum
treatment. Crucially, fertility was improved without compromising milk
yield or cow health .
References to the research
Evidence of the international quality of the research is indicated by
publication in intermediate-to- high impact peer-reviewed journals. J
Dairy Science is ranked highest and Animal 8th in the category
`Agriculture, Dairy and Animal Science'; Biology of Reproduction is ranked
4th and Reproduction 8th in the category
Selected references to key outputs from the research described in the
previous section are:
1. Royal, M.D., Flint, A.P.F. and Woolliams, J.A. (2002) Genetic and
phenotypic relationships among endocrine and traditional fertility traits
and production traits in Holstein-Friesian dairy cows. Journal of
Dairy Science 85, 958-967. doi:10.3168/jds.S0022-0302(02)74155-6
2. Wall, E., Coffey, M., Simm, G., Brotherstone, S., Stott, A.W.,
Santarossa, J., Flint, A.P.F., Royal, M.D. and Woolliams, J.A. (2002)
Introducing a UK fertility index. Cattle Practice 10, 373- 378.
Available on request.
3. Gong, J.G., Lee, W.J., Garnsworthy, P.C. and Webb, R. (2002) Effect of
dietary-induced increases in circulating insulin concentrations during the
early postpartum period on reproductive function in dairy cows. Reproduction,
123, 419-427. Doi:10.1530/rep.0.1230419
4. Garnsworthy, P.C., Lock, A., Mann, G.E., Sinclair, K.D. and Webb, R.
(2008) Nutrition, Metabolism and Fertility in Dairy Cows: 1. Dietary
Energy Source and Ovarian Function. Journal of Dairy Science, 91,
3814-3823. Doi: 10.3168/jds.2008-1031.
5. Fouladi-Nashta, A. A., Gutierrez, C. G., Gong, J.G., Garnsworthy, P.
C. and Webb, R. (2007) Impact of dietary fatty acids on oocyte quality and
development in lactating dairy cows. Biology of Reproduction, 77,
9-17. Doi: 10.1095/biolreprod.106.058578
6. Garnsworthy, P.C., Fouladi-Nashta, A.A., Mann, G.E., Sinclair, K.D.
and Webb, R. (2009) Effect of dietary-induced changes in plasma insulin
concentrations during the early postpartum period on pregnancy rate in
dairy cows. Reproduction, 137, 759-768. Doi: 10.1530/REP-08-0488
Underpinning research projects:
a. 1995-1998: MAFF: Postgraduate Studentship "Quantitative analysis of
genetics of pregnancy failure in cattle". Awarded to A.P.F. Flint
(Nottingham) vice M Royal, £28k.
b. 1999-2000: Improvement of reproductive efficiency in cattle. A.P.F.
Flint (PI) (Nottingham led plus Roslin Institute) MAFF/MDC/SOAEFD, 99/R4/02,
c. 2001-2005: Developing a Fertility Index. A.P.F. Flint (PI) and R.Webb
(Nottingham led plus Roslin Institute and SAC Edinburgh). LINK (Defra,
Holstein UK, Genus ABS, National Milk Records, Livestock Services UK,
Cogent Breeding, Dartington Cattle Breeding Centre), LK0639,
d. 1999-2000: Improvement in the reproductive efficiency of cattle
through the short-term manipulation of nutrition. R. Webb (PI) and P.C.
Garnsworthy (Nottingham led plus Roslin Institute). DEFRA LS0204 -
Bridge LINK, £567k.
e. 2001-2005: Nutrition and fertility in dairy cows. R. Webb (PI) and
P.C. Garnsworthy. (Nottingham led plus Roslin Institute and SAC Aberdeen).
LINK (SEERAD, ABNA Ltd, BOCM PAULS Ltd, Provimi Ltd LK0646, £382k.
f. 2001-2006: Nutrition and fertility in dairy cows. R. Webb (PI) and
P.C. Garnsworthy. (Nottingham led plus Roslin Institute and SAC Aberdeen).
DEFRA Strategic grant LS3306, £2.02m.
g. 2006-2007: Improvement of dairy cow fertility through studies of liver
metabolism, molecular markers and oestrous expression. P.C. Garnsworthy
(PI), R. Webb and A.P.F. Flint (University Of Nottingham). DEFRA AC0205,
Details of the impact
This research arose out of the urgent need to address the worldwide
decline in fertility of dairy cows, as outlined in Section 2, which was
attributed to a combination of genetic and nutrition-related factors.
Fertility had been in decline for 40 years, so a quick fix was not
Dissemination and uptake of any innovation takes time and it can be many
years before benefits can be quantified. In the dairy industry,
reproductive performance is measured only once per year, the generation
interval is 5 years and cows stay in the herd for up to 10 years.
Nevertheless, the latest statistics indicate that fertility is improving,
both genetically and phenotypically, and will continue to improve for
generations to come.
Bull proofs for fertility were first made available to the breeding
companies involved in the project in December 2003. Although originally
made publicly available through the Milk Development Council website in
2005, the Fertility Index has become firmly established and increasingly
important in the 2008-2013 period (Sources 1-3). The Index
provided producers, for the first time, with the facility to select bulls
on the basis of daughter fertility. The production of the Fertility Index
is managed through DairyCo (DairyCo is the levy board which utilises dairy
farmer levy payments in Great Britain), with a spin-out company based at
Scottish Rural College (eGenes) established to collect and analyse the
relevant data from the industry.
Analysis of national artificial insemination records shows fertility
trends in bulls and cows (Figure 1; Source 1). Genetic merit of AI
bulls for calving interval flattened off after release of the Index to
breeding companies, indicating an early effect upon fertility trends. When
farmers started using the Fertility Index to select bulls, the fertility
trend was reversed. The rate of reduction from 2008 to 2012 was 20% faster
than the rate of increase from 1990 to 2000, showing an accelerated rate
of improvement in fertility. In cows there was a slowing in the rate of
increase genetic merit for calving interval and a reversal from 2008
onwards, showing that choices of bulls were feeding through into their
daughters' performance. Daughter performance is reported by year of birth;
hence the latest data are for cows born in 2010.
The Fertility Index has become firmly incorporated into international
genetic evaluations through Interbull (a subcommittee of the International
Committee for Animal Recording) (Source 1) - see Interbull (2012)
(Source 2). It is also widely used by international breeding
companies to promote superior bulls (e.g. WorldWide Sires [Source 3]).
The main deliverable of the UoN nutritional research was a new way of
thinking when evaluating dairy cow nutrition in relation to milk yield and
fertility - the industry now considers not only nutrient supply, but also
the effect of diet on metabolic hormones, and their influence on the
reproductive system. The three commercial partners in UoN LINK programmes
(LK0646 [e]) are well known for their innovative approaches to
dairy cow nutrition. BOCM PAULS is market leader in UK dairy compound
feed; AB Agri is the leading UK supplier of blended feeds for dairy
cattle; Provimi is a world leader in animal nutrition with plants in 27
countries. BOCM PAULS and Provimi incorporated UoN predictive equations
into their ration formulation programmes to provide nutritional indexes
for insulin and progesterone as aids to fertility.
The Head of Ruminant Development at BOCM PAULS stated: "Our goal is
to improve fertility and longevity by focusing on extending the
productive life of the cow and reducing the costs associated with
infertility and high replacement rates. The Nottingham fertility
research provides a central feature of our approach, by predicting the
likely influence of nutrition on metabolic hormones, particularly
insulin, and consequences for fertility. To this end, we incorporated
fertility indexes for insulin and progesterone into our ration
formulation packages. Every dairy cow ration that we have designed since
2008 incorporates an assessment of potential effects on fertility. Using
this approach, we have seen significant improvements in fertility on
many dairy farms. In 2012, BOCM PAULS became part of the ForFarmers
Group, the largest feed company in Europe with a turnover of € 6.6
billion. As part of the integration process, we have shared technical
information and ideas with partner companies in the Group. Thus, the
concepts generated by the Nottingham fertility research are being
implemented in dairy nutrition programmes throughout Northern Europe"
(Source 4). Feed companies not associated with the project have
also incorporated concepts generated by UoN into marketing material, e.g.
Volac (Source 5). The findings are incorporated into advice to
farmers from DairyCo on feeding for fertility (Source 6).
Data confirm that practical application of genetic, nutritional and
management tools reversed the decline in fertility among cows. Between
2000 and 2008, average calving interval of UK Holstein cows increased
at the rate of 4 days per year; between 2009 and 2010, the interval decreased
by 4 days (Source 7). This rapid trend reversal is highly
significant. If maintained, rate of restoration of fertility will be 5
times the rate of genetic progress. As the genetic gain in fertility
occurs year on year, it is therefore cumulative over time.
In 2012 DairyCo estimated that the typical UK herd was losing
£250/cow/year through poor fertility. A shorter calving interval would
save £2/cow per day of interval reduction. On this basis the savings
associated with improving fertility amounted to £16m nationally in
2009-2010. Genetic trends suggest that improvement will continue so, by
2020, annual savings will approach £100m. Approximately half of this can
be attributed to the Fertility Index and half to better nutrition and
management (Source 8).
Sources to corroborate the impact
- Head of Genetics DairyCo. Will provide corroboration for
incorporation of research information into UK Fertility Index leading
to significant improvement in genetic merit for fertility of UK dairy
- Interbull (2012) http://www-interbull.slu.se/Female_fert/framesida-fert.htm.
Corroboration for use of UK Fertility Index in International genetic
- World Wide Sires (2012) Addressing dairy cow fertility through better
Corroboration for use of Fertility Index information in promoting
genetic merit of dairy bulls on the international market
- Head of Ruminant Development BOCM PAULS LTD. Corroboration for the
incorporation of nutrition equations for insulin, progesterone and
fertility into their ration formulation packages. 2013
- Volac (2009) http://www.volac.com/news/agriculture-news/news156/fertility-remains-among-the-major-issues-in-dairy-herds.
Corroboration for use of nutrition research by companies outside the
- DairyCo (2013) http://www.dairyco.org.uk/technical-information/feeding/planning-your-nutrition/nutrition-and-fertility/.
Provides corroboration for incorporation of nutrition research into
independent advice on fertility given to dairy farmers.
- Centre for Dairy Information (2013) Breed Performance Statistics
Provides corroboration for phenotypic (genetic plus nutrition and
management) improvement in fertility of dairy cows from 2009 to 2010.
- DairyCo (2012) PD+ Fertility Improvement Programme. http://www.dairyco.org.uk/resources-library/technical-information/fertility/pdplus-section-5-establishing-your-starting-point/
Corroboration for cost of poor fertility and value of improvements
through genetics and nutrition.