Jeremy Bryant NZ Animal Evaluation Ltd Manager How fertility is dealt with by the NZ dairy industry - genetics and environment Jeremy Bryant NZ Animal Evaluation Ltd Manager

Introduction Fertility came in focus in the late 90’s NZ was less impacted Need cows that calve every 365 days

Reproductive performance in NZ 6-week in-calf rate Non-pregnancy (‘empty’) rate Xu & Burton, 2003 Fertility Monitor Report 10 20 30 50 40 60 70 90 80 100 % 5 17 57 68 78 Overall Lower quartile Upper quartile (36 – 90%) (1 - 32%) Seasonal calving is underpinned by seasonal breeding. The ultimate performance indicator for seasonal breeding are the rate with which the herd gets pregnant during a defined and limited period of 10-14 weeks. Two overall measures are the 6-week in-calf rate and the non-pregnancy rate (which we call ‘empty rate’). On average, the farmer can manage reproduction so that 68% of cows get pregnant during the first 6 weeks of the seasonal breeding program. But there is substantial variance around this, with the mean of the top-quartile herds achieving 78%. At the end of the seasonal mating period (10 -14 weeks), those cows which failed to get pregnant average 10%, but again there is substantial variance among herds. Cows that fail to get pregnant are generally culled, which is a great waste to the farmer and the industry as a whole.

Reasons for culling in NZ ≈ 50% on repro. 4% 6% 9% 45% 16% 16% Herd replacement rate ≈ 20% p.a. In fact, if we look at the reasons for which cows are culled in NZ, nearly half of it is dues to cows failing to get pregnant during the 10-14 week seasonal breeding period. It’s certainly half when you add ‘due lates’ and abortions as other reasons for culling. Average replacment rates in NZ are 20%. Farmers would much prefer to have these heifers replacing poor producers or cows with a history of mastiits or lameness. Xu & Burton, 2003 Fertility Monitor Report

National Breeding Objective “animals whose progeny will be the most efficient converters of feed into farmer profit” Breeding Worth (BW) = $ net farm income/5 tonne of DM

Genetics in NZ Multi-trait model – since 2006 Presented for mating - Parity 1-3 Calving rate within 42 days of calving start (CR42) - Parity 2, 3, 4 270 day milk volume yield (Parity 1) BCS (Parity 1) Low heritability but lots of genetic variation New Model (potentially 2017) Gestation length of animal itself Use heifer calving information

Genetic Trends

Fertility BV Validation. It works ! Avg. Fert. Herd Low Fert. Herd High Fert. Herd Every +1 Fertility BV = -0.17 day mean calving date (MCD) -0.17d +1.19% -0.83d +1.31% -0.81d +1.10% -0.17d +1.40% -1.15d +1.59% -1.16d +1.49% -0.19d +0.84% -0.52d +0.90% +0.66% 2 yr old Every +1 Fertility BV = 1.19% increase in cows presented for mating in 21 days (PM21) Fertility BV is more important in low than high fertility herds 3 yr old 4 yr old

It works ! Fertility Validation Avg. Fert. Herd Low Fert. Herd High Fert. Herd Every +1 Fertility BV = -0.17 day mean calving date (MCD) -0.17d +1.19% -0.83d +1.31% -0.81d +1.10% -0.17d +1.40% -1.15d +1.59% -1.16d +1.49% -0.19d +0.84% -0.52d +0.90% +0.66% 2 yr old Every +1 Fertility BV = 1.19% increase in cows presented for mating in 21 days (PM21) Fertility BV is more important in low than high fertility herds 3 yr old 4 yr old

Fertility Research Herd Purpose build for extremes in genetic fertility, but balanced for other key traits Currently have 540 8-10 month-old heifers Focussing on underlying reasons for fertility divergence as well as markers for increasing the rate of genetic gain in fertility www.dairynz.co.nz/animal-model This work is funded by: Ministry of Business, Innovation and Employment New Zealand dairy farmers through DairyNZ Inc.

InCalf (NZ) 2008

Fertility fundamentals Rear calves and heifers well reach target weights First mating bull power, start mating earlier for heifers, calving ease bulls First calving BCS of 5.5 at calving 2nd mating pre-mating heats, treat anoestrus, focus on heat detection Pregnancy Prepare cows so they reach BCS of 5 at second calving

Fertility Focus Report Answers 3 key questions: Where is the herd now? What improvements are realistically achievable for the herd? What areas for improvement should I be focusing on?

Conclusions Gains can be made by improving environment/management and genetics Genetics works National breeding indices include a strong focus on fertility Secondary selection possible Fertility fundamentals Significant gains can be made by focusing on some key principles

6-week in-calf rate trend 78% NZ Dairy Statistics 2014-15