VETCARE GRAZING

THE SITUATION

What a winter so far!!!  As I write this newsletter most of the backcountry roads are closed with either slips or floods. A bridge has collapsed on the road to Mangamahu one of our biggest farming districts isolating the local residents. Feed is rapidly disappearing due to the wet and cold conditions. There are hundreds of slips in the hill country, far more than Feb 2002

However our Graziers are battling on in the mud and rain and are keeping the heifers under their care growing quite well considering the hurdles. Some have had too or going to buy in more supplement. Two graziers so far have purchased palm kernel. I continue to be impressed with this product. Heifers do well on it. The high oil content and quality fibre provides sufficient energy particularly on cold days to keep stock healthy and growing. It is very safe to use as there is no risk of lactic acidosis as it is low in carbohydrate. Palm kernel is very cost effective compared to other supplements (See following article on silage analyses). When fed adlib they are eating 1.5-2.0kg per day

We are keeping a close eye on your stock through this difficult period and helping and giving advice to the Graziers as necessary.

Despite the stress, stock health for the most part has been very good with very few problems.

HEIFER REARING

Recent trial work by Dexcel has shown that heifer rearing should be considered in two parts

• Up to puberty
• After puberty

If weaners are grown too well they can reach puberty at too young an age before the mammary gland has developed sufficiently which will result in reduced potential milk production in later life. Conversely if heifers are grown too slowly they will not reach puberty by 15 months of age when they are joined with the bull. The key is steady growth right through to mating.

In NZ in my view very few lines of weaners are grown too well. Usually they are not grown well enough. It does occur overseas when a lot of concentrate is fed with the development of what is called the fatty udder syndrome. I guess with more calves being fed meal and palm kernel through the summer/autumn period now one needs to keep a check that they are not being overfed and getting too fat. Also from our own observations over fat weaners are inclined not to get in calf as well.

 The goal is to get heifers to the following live weights at given ages based on mature live weight then there won’t be a problem.

Live weight targets (kg) for replacement heifers based on mature live weight

This table is a guide. There is a lot of difference in genetics between and within herds so allowance should be made for this when working out your own targets. We use this table as a guide as well as taking genetics into account when setting targets for your heifers on the grazing scheme.

Provided heifers have not been grown too quickly before breeding, the Dexcel work has shown that heifers grown to 90% compared with 80% of predicted mature live weight at 22 months of age produce more milk solids in their first lactation

• Holstein-Friesian heifers weighing 455kg at 22 months of age produced 18kg more MS than heifers at 385kg
• Jersey heifers weighing 375kg at 22 months of age produced 12kg more MS in their first lactation compared with Jersey heifers at 320kg

PREGNANCY TEST RESULTS

 EMPTY RATE 2006

Note that the Jersey empty rate is higher than the crossbred, which is higher than the friesian. The Ayrshire rate only includes a few heifers.

This pattern has been the same for the last 12 years that we have kept preg test records as follows.

 EMPTY RATE 1994-2006

There is a statistical difference between the xbred/friesian versus jersy empty rate over this period. Unfortunately the friesian and cross bred figures have been lumped together. However anectodally we are sure that the friesian heifers would have had a lower empty rate than cross breds over the 12 year period. We are keeping the breeds separate now so it will be interesting to see if this years trend continues.

Overall empty rates have trended down wards over the years which in part is due to more heifers being vaccinated against BVD and the use of certified and BVD virus free bulls.

 HEIFER FERTILITY

The following measures have been implemented over the years as part of quality assurance and best practice to improve in calf rates and minimise the risk of empty heifers

• Encouraging dairy farmers to vaccinate their calves against BVD and IBR (nasal cattarh) with a booster given prior to mating. BVD has proven to have a major influence on fertility with some lines of heifers over the years. Virtually everyone vaccinates now. Those that aren’t are advised to do so.
• Vaccinate against Neospora where there is a need.
• We only use certified bulls i.e.
• Bulls that have passed a testicle check.
• Bulls that have passed a health check.
• Bulls that are above specified minimum weights and condition.
• Bulls that are blood test BVD virus antigen negative and EBL antibody negative.
• Bulls that are vaccinated against BVD, IBR and Leptospirosis
• Bulls that are Tb test negative
• Bull ratio no greater than 1:30. No greater than 1:20 if requested.
• Always at least 2 bulls with every mob of heifers no matter how small the mob is as insurance.
• At least one 2-year-old Jersey bull included when Jersey bulls used.
• Bulls out for at least 3 cycles.
• Heifers on rising plane of nutrition through mating.
• We try and avoid getting heifers over fat before mating
• Aim to achieve mating weights of 60% of mature weight i.e 225kg and 300kg for Jerseys and Friesians respectively with Xbreds in between to avoid non-cycling heifers at mating.

It is interesting, when we look at our data over the last 12 years, that there are significant differences between lines of heifers i.e. some lines consistently have low empty rates year after year e.g. below 3%, other lines are consistently higher year after year e.g. above 8% despite exactly same management and feeding practices. There is no doubt in our mind; there are fertility differences between different lines of heifers. To identify what all these differences are is difficult. BVD virus and Neospora will account for some of it, but I believe genetic differences account for a lot of it

 HIRE BULLS

Over and above the bulls we need to cover the heifers on the grazing scheme there will be others available for you to hire for your own herds. Purebred 1 and 2 year old Jerseys, Herefords and Angus. If you need some bulls or want more information contact us now before they run out.

There is a limited supply. Preference is given to clients grazing heifers with us.

• All bulls are quality assured
• TB free
•  Vet checked
•  BVD virus negative
•  Vaccinated against BVD, IBR and Leptospirosis.

 HOW GOOD IS SILAGE?

The following table compares the nutritional analyses of 3 different silages made on one of our client’s properties compared to palm kernel. The silages were analysed because stock performance was not as good as expected based on the intake they were getting.

The results highlight that none of the silages were top quality for differing reasons.

SILAGE NUTRITIONAL ANALYSES COMPARED TO PALM KERNEL

INTERPRETATION

Dry matter           
Target DM% for grass silage is 30-35% for stacks and 35-45% for bales. Grass silage with a DM below 30% will produce some effluent and below 25% effluent losses will be considerable. Effluent losses result in nutrient losses particularly protein and sugar. Dry matter levels greater than 50% makes compaction difficult and results in poorer fermentation and increased risk of moulds and fungi growth

Organic matter
Describes the amount of usable material in the feed. Higher the better. Pasture is usually 87 to 91%

Crude protein
Good protein content is essential for building animal protein and enabling high growth. A minimum of 12% CP is required for good growth. >14% is better.

Acid Detergent Fibre (ADF) and Neutral Detergent Fibre (NDF)

NDF measures the hemicellulose, cellulose and lignin (fibre fractions from the plant cell wall) and ADF measures cellulose and lignin content. Lignin is the least digestible fibre fraction and hemicellulose is the most digestible fibre. As grass matures or silage is made from more mature grass the proportion of lignin increases, so the grass becomes less digestible and has lower energy level. In general the lower the NDF and ADF values the higher the energy level.

Fibre is particularly important for rumen health. Too much fibre will slow down the rumen, through put, take up space and reduce feed intake and production. Too little fibre will speed up the rumen, rapid through put, increase intake but appetite is not satisfied because intake is limited due to bulky slushy feed (too much water). This also reduces production.

Ideally for optimum production NDF 30-45% ADF 20- 30%

When grass has an NDF below 30% which can occur when grass is rapidly growing in spring and autumn higher NDF silage will help balance the fibre content.

Digestibility                 
Describes the proportion of organic matter in the feed that can be digested. The digestibility will be lower when there is higher percentage of indigestible lignin fibre component. Over 70% is excellent, 55-70 is average and <55% is poor

Metabolisable Energy (ME)              
Describes the quantity of energy in megajoules that is available for animal metabolism and growth. The higher the better. Over 12.0 is excellent. 9-12 is average. <9 is poor

Fermentation Quality
pH       The pH of silage should always be related to the DM%. The wetter the silage the lower the pH needs to be to achieve stability during storage. A really well fermented excellent silage should have a
pH level below 4.3 at 30% DM
pH of 4.6% at 35% DM
pH of 4.9 at 40% DM (see notes)

Lactate (Lactic acid)    This is the best acid for bringing the pH down quickly and preserving silage and a high level is good. This is also related to DM%, the wetter the silage the higher the lactic acid%. Should be 6-8% for wet silage and 3-4% for dry silage. The lactic acid level will be higher in inoculated silages.

Ammonia- N/ Total-N            This is a measure of protein breakdown and low is good. <5% is excellent, 5-10% good, 10-15% poor and >15% will seriously reduce silage palatability and intake. High levels indicate poorly made silage with poor fermentation and high protein breakdown

SUMMARY

All 3 silages were harvested at a more mature stage of growth than is ideal for optimum silage and stock performance. A lot of seed head. This is reflected in too high fibre content (NDF and ADF), lower digestibility and lower Metabolisable Energy (ME).

In addition the protein level in the oatage and pasture silage is below optimum for top growth. A lot of protein has been lost due to degradation due to poor fermentation. This is reflected in the very high Ammonia N levels which would have affected palatability and intake and perhaps caused a degree of rumen acidosis. Protein is converted to ammonia. Soluble sugars will have been lost at the same time.

As well silage pHs are too high and lactate too low confirming that the silages have not been well fermented.

When comparing the cost of these 3 silages per unit of ME with palm kernel, palm kernel comes out tops.
 
The moral of the story is; to get the very best return from silage it must be harvested at the right time and processed precisely otherwise it can become a very expensive ‘filler’. There are a lot of variables when it comes to making silage particularly timing including the weather, stage of growth, pasture species composition, contractor availability and most important how well the silage is made and use of inoculant.

From my experience there is a lot of silage and baylage being made that is substandard, making it expensive as well as resulting in below par stock performance. Food for thought!!

RESEARCH

Poukawa On – Farm Research Ltd, Hastings with funding from Dairy Insight are about to do research work focusing on how different calf rearing systems might impact on the long term growth and lactation performance of dairy heifers. We will follow this work with interest and keep you posted.

WEANER GRAZING

Those of you that want weaner grazing, please be in early and contact Jamie. There will only be a limited supply of suitable weaner grazing available. We never have enough to satisfy all the demand. We have great difficulty finding sufficient top quality weaner grazing that is necessary to grow weaners well. We won’t offer grazing unless we are happy with it.

ARTIFICIAL INSEMINATION

We do provide a synchronised AI service for anybody wanting it. If you haven’t already specified you wish to AI your heifers please let me know asap. We will give you a quote before hand.

VISIT

Jamie intends to visit all our Clients in the near future starting after the busy calving period. If you have any concerns or queries in the meantime don’t hesitate to contact us. We are always available.

Kind Regards

John Pickering
Veterinarian