In April 2020, the Industry Standards Committee of Lactanet Canada proposed recommendations allowing greater flexibility in the requirements for publishable lactations and official genetic indexes for production traits. These recommendations, which were approved by the Lactanet Board of Directors, aimed to recognize the unavoidable impact of Covid-19 on milk recording services and to minimize that impact to Canadian dairy producers. As the Covid-19 period continues, and is expected to do so for the foreseeable future, Lactanet will continue to monitor and assess the Covid-19 situation across the country, which is different by region and changes over time. When risks are low and milk recording staff can safely deliver services in person, expectations are that regular testing intervals and supervision occur. The more flexible requirements allowed during the Covid-19 period are intended to limit the negative impact for those times when Lactanet cannot safely deliver services in person.
At Lactanet special programming has been implemented to apply the more flexible requirements for lactations that do not otherwise meet all requirements to achieve official publishability status. Only lactations in herds that were known to be enrolled on a publishable level of milk recording at the time of their latest test during the period from January 1 to March 14, 2020 qualify for this reprocessing due to Covid-19 exceptions. Briefly, the following summarizes the key minimum standards for official publishable lactations that have been modified as part of the special processing due to Covid-19:
- Maximum interval between test days extended from 90 to 110 days.
- Minimum number of herd tests per rolling 12-month has been reduced by two, which becomes 8 instead of 10 for herds on alternating Supervised/Unsupervised or AM/PM testing or becomes 6 tests instead of 8 if enrolled on a 24-hr supervised testing program.
- Minimum Lactation Rating for Protein has been lowered by 5 points to become 90 for lactations reaching at least 305 days in milk (instead of 95), or 85 if the lactation is terminated between 240 and 304 days in milk.
- Test days that would normally have been Supervised but could not be due to Covid-19 no-contact milk recording service restrictions have still been labelled as such even though no supervision was performed.
Within qualifying herds, the lactations that are included in this special processing are those with a test day since March 13, 2020. Depending on the length of time that Covid-19 will continue to affect milk recording services across the country, Lactanet Canada will determine when this special processing for publishable lactations will transition back to the usual minimum standards.
Official Cow Genetic Indexes for Production
The extended interval between test days that resulted in some herds due to the impact of Covid-19 on milk recording services could also impact the official status of cow genetic indexes for production traits. For this reason, starting with the August 2020 genetic evaluation release, Lactanet also implemented temporary modifications of this requirement as outlined in Table 1. Basically, depending on the number of usable test days during the current lactation that are included for the cow’s genetic evaluation, the maximum allowable average interval has been extended as required under the scenario where herd testing was reduced as far as 60-day intervals. As for the relaxation of publishable lactation requirements outlined above, Lactanet will also determine the duration of this temporary modification to the requirements for official cow indexes for production traits.
Summary
Lactanet Canada and its Industry Standards Committee understand the challenges that Canadian dairy producers have been facing during the period of time where Covid-19 affects the manner in which milk recording services can be offered by Lactanet field staff. For this reason, the usual requirements for publishable lactations and official cow genetic indexes for production have been modified and applied to cows in herds that were on a publishable milk recording service prior to the start of Covid-19 in March 2020. Although the relaxed requirements are temporary in nature, they will remain in place for the foreseeable future and then Lactanet will transition back to the usual industry standards.
S-S-I- Legacy Method is the new #1 gPFT bull in the Italian August 2020 index run is at gPFT 4700. Gen RAVE is one of the highest debutants this index run in the official Italian ranking, he is a bull which is in the Top 10 of many other rankings: Rave is a RIO x FINDER x RACER and he is the #10 gPFT bull in Italy with gPFT +4488. Sound System is very strong on the 1st position in the Italian daughter proven PFT ranking with PFT +4193, more than 300 points higher than the #2 PFT.
AOT Silver HELIX is not only the #1 daughter proven GTPI bull in the breed (4/20 GTPI +2997) he is also the #1 daughter proven RZG bull (RZG =159). The Top 5 daughter proven sires based on RZG are followed by the international bulls Silver son Griff (RZG 158), the 2 Supershot sons Topshot and Windmill (RZG 157) and the Spring son AltaMarlon. The Gazebo son Gladius from the German AI Rinder Allianz leads the ranking for genomic RZG bulls at RZG 169, followed by Genosource Captain at RZG 168, this Charl son is as well the #1 GTPI bull in the USA (4/20) at GTPI +3059 / NM $ 912. The international sire of sons Gen RAVE increased 2 RZG points up to RZG 163.
We can see in Figure 1 that the rate of difficult births to Holstein heifers has decreased substantially over time. This is exciting news -selection for better genetics and improvements in calving management practices have resulted in less dystocia and fewer stillbirths! Cows and calves are healthier, and producers obtain more realized income from investing in better genetics.
The spread (variation) in the data will decrease, too. Figure 2 shows the distribution of traditional PTAs (without genomics) for sire calving ease in Holsteins for April and August. The differences between the two curves are very clear. In April most Holstein bulls fell between 4% and 12% for SCE. Come August, most Holstein bulls will range from 1 % to 4% SCE. The range of all calving traits will decrease for both Holstein and Brown Swiss, and there will be fewer bulls with extreme PTAs. Changes to the genomic PTAs will be very similar.
Producers that have used a hard PTA cutoff for calving traits, along with a selection index, can stop using that selection threshold to exclude undesirable bulls. The selection index will ensure that the calving traits are given proper emphasis when ranking bulls.
