Steve Morris: 45 years of beef-cattle research
At the New Zealand Society of Animal Production (NZSAP) conference each year since 2011 there has been a "Living Legend" address.
"This is a society invitation to a distinguished long-term member to make a scholarly presentation on their life’s work to the Annual Conference."
For the 2019 conference we were lucky to have Professor Steve Morris presenting his life's work in beef cattle research.
Both Izzy and Riri enjoyed his talk thoroughly and we hope that you enjoy our summary of it!
The beef industry
The NZ cattle herd in 2018 comprised of 6.6 million dairy cattle and 3.68 million beef cattle. This 3.68 million beef cattle was made up of 968,000 beef breeding cows that produced approximately 800,000 calves per year. Other sources for the beef industry include calves produced from the dairy industry; namely dairy-beef crossbreds and bobby calves.
As can be seen in the graph below, there has been considerable variation in the numbers of beef compared with dairy cattle in NZ over the years. Interestingly, from the 1960's until early 2000's there were more beef than dairy cattle!
In terms of economics, NZ beef exports were worth $2.99 billion in the year end September 2018. Further value was in the "co-products" such as hides, tallow, pet food and oils and fats, worth $602 million.
Early-career research: post-partum oestrous interval
Steve's masters thesis was titled "A study of some factors affecting the post-partum oestrous interval in suckled Angus cows". He determined there was a negative correlation between date of calving and length of the post-partum oestrous interval in beef cows. This means that later calving cows resumed cycling sooner than earlier calving cows.
Practically, this meant that any attempts to calve heifers earlier than the main herd in an effort to offset the shorter post-partum oestrous interval of two-year-old heifers compared with older cows was ineffective because of this negative relationship between calving date and post-partum oestrous interval.
Beef-cow nutrition and efficiency
Buffering capacity of beef cows
A big chunk of the research at Tuapaka in the 1970s was related to the nutrition of hill-country grazed beef cows. This was where the term "buffering capacity" came from and is the term to describe liveweight loss during winter to get through this low pasture growth period.
Based on these studies, it is recommended that cows can lose 10% of their weight from autumn (weaning) until calving without having detrimental effects on their performance or their calf's performance.
Cows can also be fed below maintenance and lactation requirements in early lactation with no effects on calf growth rates. Steve found that from calving until day 65 of lactation (approximately 2 months), Hereford x Friesian heifers could graze pasture swards of 5-6 cm with no impacts on calf or heifer performance compared with if they grazed pasture swards of 9-10 cm.
This research is hugely practical as farmers have more options to manage pasture supply and demand on sheep and beef farms with a beef cow herd.
The research at Tuapaka in the 1970s was based on Angus cows that were 430 kg at weaning time. In 2018, the Angus cows at Tuapaka were on average 600 kg mature weight. This substantial increase in weight can be attributed to genetic selection for improved growth rates in beef animals (200, 400 and 600 day weights) without a restriction on mature liveweight.
This is a potential concern for the industry, with bigger cows come increased feed requirements and a reduction in efficiency. With bigger mature cows come other undesirable features such as increased treading damage or greater methane output per kg produced by the beef cow.
Body condition score
Body condition score (BCS) has been used as an aid to monitoring the feeding of beef cows and is a more accurate representation of body reserves and the change in body reserves compared with using live weight alone.
Most older studies use a 0-5 scale and recent studies use a 1-10 scale (like Izzy's NZSAP paper that we will summarise at a later date!).
Steve's work from 2006 showed that one BCS unit was approximately 60 kg on a 0-5 scale and more recent work with Beef + Lamb suggests that one BCS unit was approximately 27 kg on a 1-10 scale for cows that were 520 kg in mature weight.
Residual feed intake and feed efficiency
Since 2000, residual feed intake (or RFI) has increased in use as the measure of feed efficiency in animals. It is the difference between an animal's actual feed intake and it's predicted feed intake that is based on equations for maintenance, production and changes in weight.
An animal with a negative RFI value is a more efficient animal than one with a positive RFI value.
Steve and his team used the semen from Australian Angus bulls that had low RFI breeding values (high feed efficient genetics) and bulls that had high RFI breeding values (low feed efficient genetics) to inseminate NZ Angus cows.
Importantly, these bulls were tested for RFI in Australia under grain-feeding conditions.
The heifer calves from these matings were monitored for herbage intake and RFI at 350 and 450 days (approx. 12 and 15 months of age). Interestingly, there were no differences between the heifers that were sired by low or high RFI bulls.
The heifers were monitored until after their own calving and there were also no differences between the two lines in pregnancy rates, calving dates, birth weights, milk production or calf weaning weights.
From these studies it was concluded that RFI (especially RFI measured in a grain-based system) may have only a minimal impact on cow performance in our hill-country grazing systems in New Zealand.
Breeding heifers at 15 months of age
Calving heifers for the first time at 2 years of age instead of 3 years of age is a potential way to increase herd performance and profitability. This increased profitability of calving heifers at a younger age is dependent on the level of assistance required when calving.
It was thought that restricting nutrition during the first 3 months of pregnancy could control birth weight of calves to reduce the incidence of dystocia (calving difficulty).
However, if you read our post on calving difficulty, you know that this was not the case! There was no effect of a low vs moderate weight gain of 15-month-old Angus heifers on calf birth weight or calving difficulty.
Another hunch from industry is that the body dimensions of calves had effects on the incidence of dystocia. One of Steve's PhD students at the time measured MANY body dimensions of calves and found that other than birth weight, sex of the calf and weight of the heifer, none of the body dimensions measured were associated with dystocia.
Crossbred cows - what is the most efficient beef cow?
The efficiency of a beef cow is increasingly important. Her role in the hill-country farming system means that the pasture quality and quantity available to her is dependent on the needs of the other stock classes on the farm.
A long-term project that was funded by Beef + Lamb NZ evaluated the performance of 4 breed groups of cows over their lifetime to determine the performance of beef X dairy cows compared with straight-bred Angus cows.
The four groups were:
Angus X Friesian (AF)
Angus X Kiwicross (AK)
Angus X Jersey (AJ)
The four groups were compared for many production traits such as; age at puberty, reproductive performance, efficiency of calf production, lifetime productivity, growth rate and meat quality from their progeny.
Stayability (percentage of cows remaining in the herd) was not different for the 4 groups up to the birth of their 7th calf.
The Angus X dairy (AF, AK and AJ) cows weaned heavier calves than the Angus (AA) cows did (blue bars in Figure 2).
As a percentage of cow weight (weaning weight ratio; purple bars in Figure 2), AK and AJ cows had the greatest weaning weight ratio, followed by AF, with AA cows having the lowest weaning weight ratio.
Over the course of the study, cows were bred to Hereford, Simmental, Angus or Charolais bulls. Two cohorts of calves were followed through to processing and there were no differences in carcass or meat quality.
Conclusions from this project were that:
"An advantage of using Angus-cross-dairy cows is the ready source of replacements, allowing the cows to be bred to terminal sires, which further increases the efficiency of the herd."
Beef production from the dairy herd
There have been estimates that close to half of NZ beef is from dairy origin (i.e. dairy bulls, cull cows and bobby calves).
In 1981 a commercial bull-beef unit was established at Tuapaka farm with a focus on per hectare production. Results of the bull-beef unit were improved carcass weights from 200 to 239 kg with a recommended target of 500-600 kg beef per ha.
Other research included grazing management for Friesian bulls during autumn to spring, crossing Friesians with double muscled breeds (Piedmontese and Belgian Blue) with no difference in growth rates or final weights but better carcass and meat gain for the double-muscled bulls.
Recent studies have used alternative forages such as chicory, plantain and clover mixes to improve Friesian bull growth over the summer dry period with promising results.
A once-bred heifer production system is where heifers have one pregnancy and lactation before being processed as meat-producing animals. This is done in beef X dairy heifers.
The timing is important as after 30-36 months of age, heifers are classed as cow beef instead of heifer beef if they have more than 6 permanent incisor teeth. To be successful, heifers need to grow fast before their first calving.
Results from studies by Steve and his team found that there were only small differences in meat quality of the once-bred heifers compared with unbred heifers.
The most recent project that Steve has been involved with is the new-generation beef project which is looking at alternative options for surplus dairy cattle instead of bobby calves.
One of these options is to process animals at around one year of age, before their second winter. Preliminary studies compared animals (Hereford X dairy) slaughtered at 8, 10 or 12 months of age and the potential meat quality of these younger animals compared with the traditional 18-24 month old processing age.
The reduced time on farm would offer potential environmental benefits by having less nutrient losses and greenhouse gases.
Steve's concluding comments
"I have thoroughly enjoyed the last 45 years of beef cattle research and would especially like to thank my colleagues and student co-workers (particularly those from offshore) who were always fun to work with and to visit once they returned to their home countries."
Steve is optimistic of the NZ beef industry, he believes (and we agree!) that the beef industry is an unsung hero of NZ pastoral farming and that it will remain so heading into the future.
Give us a bell if you want us to post a more detailed summary on any one of the studies mentioned above (Facebook or email: email@example.com).