To date, Pillars has successfully trained 5 interns, 2 Masters students, 8 PhDs and 4 Post-Doctorates. Many of these emerging scientists have continued within the Pillars programme, enabling further career progression and capability growth for dairy science in NZ.
We are currently training 5 students (1 Masters, 4 PhDs) and 4 Post-Doctorate researchers. Find out more about their research below.
Nicole Steele is a post-doctoral scientist at DairyNZ, based in Hamilton. Her research focusses on developing new measures of cow fertility using wearable behaviour-monitoring devices.
Read more about Nicole's research
This is part of a large Pillars research project, the "Puberty/Fertility Scale-Up Trial", which is testing novel, earlier-in-life indicators of cow reproductive ability for genetic evaluation. Currently, the Fertility Breeding Value (BV) is calculated based upon mating and calving records, but recent Pillars research indicates that earlier traits such as age at puberty, pre-mating cycling, or heat characteristics could predict subsequent fertility and improve genetic progress.
“We are developing practical ways to measure these novel traits across large numbers of animals”, says Nicole. “Firstly, we are characterising an age of puberty trait by blood sampling 5000 R1 heifers across 54 herds to detect elevated progesterone status”.
Given the wide variation observed between herds, her work investigating how different animal and herd management factors (e.g. mob size, weighing frequency, vaccination status etc.) influence the onset of puberty is providing valuable information to design future routine capture of this trait.
Nicole is also investigating data from a subset of 2000 of these animals who are fitted with behaviour-monitoring devices. “We want to test if automated technologies could measure age at first oestrus as an alternative trait to age at puberty, as well as other traits such as pre-mating cycling and heat characteristics (e.g. heat strength and duration) either as heifers or during their first lactation” says Nicole.
Melissa Stephen is a part of the NZAEL team at DairyNZ and is currently undertaking a PhD through the Al Rae Centre at Massey University.
Read more about Melissa's research
Her studies are part of the “Puberty/Fertility Scale-Up Trial”, where she is investigating the genetic relationships between novel, earlier-in-life traits and subsequent cow reproductive performance. If strong relationships are detected, then these new predictor traits could be used to accelerate the rate of genetic gain for fertility in the national herd.
To date, Melissa has conducted genetic analyses on an age at puberty trait estimated from monthly blood progesterone testing of 5000 heifers between approximately 10 and 12 months old. She has examined how often each herd needs to be visited to collect blood progesterone measures. “Our work indicated that the number of visits for each herd could be reduced to two, and perhaps even one, without significant effects on sire ranking or heritability”, says Melissa. “This outcome is really promising as it has important implications for cost-effective and practical capture of this trait at a large scale”. Melissa is now examining the suitability of age at puberty measures to predict key reproductive traits during lactation including timing of calving, submission, and pregnancy measures.
“I am also investigating whether a shorter anogenital distance (the distance between the anus and the genitals) is associated with better fertility genetics. This is another novel, earlier-in-life trait identified from previous research.”
Find out more about NZAEL.
Nicolas Aranciaga's PhD studies are being conducted through AgResearch and Lincoln University. His work investigates how the uterine environment contributes to early pregnancy losses.
Read more about Nicolas' research
Recent Pillars research indicates that impaired embryo development in the first week after breeding is a key factor limiting conception rates in NZ cows. “Because the early embryo depends upon the uterine environment for growth and development, it is important to understand how differences in the composition of uterine fluid affect whether or not the pregnancy fails early on”, says Nicolas.
He used various lab techniques to characterise uterine fluid relative to embryo quality and viability at 7 days after insemination. “I found that early embryo quality improved with increased number of days post-calving and increased number of oestrus cycles before breeding, consistent with previous NZ research measuring embryo survival rates”, says Nicolas. “These were associated with changes in the composition of the uterine fluid as the animal recovers postpartum”.
Nicolas’s work has provided biochemical profiles of uterine fluid indicative of a maternal environment suitable for establishing a successful pregnancy, which as potential future application for interventions to improve conception rates.
Stacey’s PhD studies at Massey University investigated the use of lying and activity behaviours as measures of animal health during the ‘transition’ period.
Read more about Stacey's research
“These 3-4 weeks before and after calving are when cows are most at-risk of ill-health,” says Stacey.
“I used a DairyNZ dataset to determine if behaviours differed between cows that remained healthy and those that developed a subclinical metabolic disorder around calving.”
Stacey’s work determined that changes in lying and activity behaviours, measured using a leg-mounted device, could be used to help farmers identify sick cows before they start showing symptoms and predict when a cow is about to calve.
She found that cows that developed subclinical ketosis post-calving spent less time lying and were more active up to three weeks before calving.
Her studies also indicated that wearable devices could detect cows with low blood calcium because they are less active and spend more time lying the day before and of calving. “Further R&D will lead to behaviour-based alert systems for farmers to identify cows at risk of going down with clinical milk fever and succumbing to other diseases,” says Stacey. “Earlier detection and, therefore, earlier intervention generally result in a better health outcome.”
Stacey is now a Post-Doctoral Scientist at Massey University, collaborating with DairyNZ to investigate subclinical ketosis in grazing cows.
Olivia’s PhD investigates how a dairy cow’s inflammatory state during the transition period affects their reproductive performance. “Some inflammation around calving is normal and it performs important functions, but it’s damaging if it is excessive or goes on too long.” says Olivia.
Read more about Olivia's research
Olivia is conducting her PhD through the University of Auckland in collaboration with DairyNZ and AgResearch. To date, she has determined some blood markers of cows that still have uterine inflammation (endometritis) at five weeks postcalving. These cows have elevated blood levels of specific inflammation markers, especially in the week before and the two weeks after calving. “In future, this could enable us to identify cows at risk of reproductive issues early on using a blood test. Early detection also allows proactive treatment options to improve animal health and welfare.”
The next phases of this research will determine whether treating cows with anti-inflammatory compounds reduces persistent inflammation and then improves reproductive outcomes. If successful, these treatments will be another tool for farmers to help improve their herd reproduction.
Charlotte recently completed her PhD at Victoria University of Wellington in collaboration with DairyNZ. She examined how genetic merit for fertility affects the cow’s oocytes (unfertilised eggs).
Read more about Charlotte's research
“Up to 30 percent of cows’ pregnancies are lost in the first week, and oocyte quality is a major factor driving this early pregnancy loss, which limits conception rates,” says Charlotte.
Charlotte’s work compared oocyte quality between cows with high (+5%) and low (-5%) Fertility Breeding Values (BV). She also examined the composition of the follicular fluid that surrounds the oocyte prior to ovulation. “The early stage of pregnancy relies on nutrients within the oocyte to support development”, says Charlotte.
Charlotte determined that high Fertility BV cows had better quality oocytes and a different follicular fluid composition, which may provide them with a greater chance of establishing a successful pregnancy.
Another PhD student at Victoria is exploring how these differences in follicular fluid composition affect oocyte function. “Ultimately, we want to use this knowledge to improve conception rates either via better genetics or management to ensure a high-quality oocyte when cows are bred”,” says Charlotte.
Charlotte is now a Post-Doctoral Researcher at DairyNZ investigating differences in heat behaviours and oestrous cycle length between high and low Fertility BV cows. Her work will determine if high Fertility BV cows have stronger or longer heats that make detection easier. She will also investigate if they have shorter intervals between heats (i.e. shorter cycles). The aim is to determine if these traits could improve the accuracy of the Fertility BV.
Massey University Masters student Jessica has been a DairyNZ scholar for two years. Last summer, she worked as an intern on a Pillars transition cow health study into supplementing synthetic zeolite, pre-calving.
Read more about Jessica's research
“Cows go through a lot of change around calving, and they’re susceptible to metabolic and infectious diseases,” says Jessica. “Zeolite reduces the risk of milk fever and we wanted to know how it affects cows’ feeding behaviours.”
“We found that zeolite-supplemented cows spent less time feeding precalving, but had a rebound in their feeding time after calving, when supplementation stopped. They also differed in their patterns of feeding during the day, which may contribute to how zeolite works to reduce milk fever.”
Jessica says being involved with this study has been “an awesome opportunity” to connect with scientists in the sector, see what careers are out there and gain experience. She will now investigate the effects of different pre-calving management on lying and activity behaviours in relation to cow health for her Masters.