MILK FEVER & MASTITIS: is there a link?
Milk fever risk peaks in the first 24 hours after calving - and although some cases may be uncomplicated, simple to treat and quick to respond - others are not.
The primary problem of low calcium (+/- low phosphorous) in milk fever cases can soon develop into secondary complications due to nerve or muscle damage from her being down, and if she is slow to respond and get up, pneumonia or mastitis can complicate things further.
As you know, calcium is responsible for muscle strength which is why milk fever cases often present as wobbly, or as down cows. But the big muscles of the skeleton are not the only muscles affected by low calcium:
- The uterus is an enormous muscle by the end of pregnancy, so low blood calcium can result in a slow calving that doesn't progress, as well as increased numbers of held cleansings/dirty cows as the uterus fails to contract after calving. In severe milk fever cases the whole uterus can prolapse after calving which is one of the true emergencies in farm vetting!
- The rumen is a massive muscular stomach and cannot contract properly with low calcium levels - notice you'll hear her start to burp again once you start running the calcium in.
- Often a milk fever cow will have a dry nose - the smooth muscle responsible for causing the sweat beading on her nose won't contract - again, a useful marker if she's not up after calcium treatment and has a wet nose - is there something else stopping her from getting up?
- The teat end has a smooth muscle sphincter that seals off the teat from the environment - a vital part of her innate protection against incoming mastitis pathogens.
- White blood cells (the immune cells) also depend on calcium to work effectively; one of the white blood cells called neutrophils are particularly susceptible.
Why does milk fever cause an increased risk of mastitis?
One of the types of white blood cells called neutrophils are an important first line of defence against mastitis bugs: these cells are made in the bone marrow and when mastitis bugs invade and release toxins, the neutrophils are activated and released into the blood to combat the attack. Neutrophils travel in the blood stream and squeeze out of the cells lining the blood vessel to get into the udder - once in the udder they trap and kill the bacteria using toxic granules carried within the cell.
Milk fever cases not only have poorer functioning neutrophils to cope with infections, but calcium is needed to keep the muscle of the teat sphincter shut - so it's a double whammy - you have a cow with open teat ends, with lowered immune function that can't get up so her teat ends are open to the conditions under where she is lying.
We've had some severe E.coli cases in freshly calved cows just lately - heat stress has also been adding to the challenge.
Mastitis is very easy to miss in a milk fever case so make sure you strip all four teats once you've put the calcium in. If she doesn't respond as you'd expect to calcium, give us a ring - if there's a toxic mastitis brewing we need to get IV fluids in her ASAP.
Always happy to discuss down cow cases with you - we're only at the end of the phone!
CALCIJECT STOCKS - an update
Happy to report we're back fully stocked with Calciject with good supplies secured at this end.
A milk fever cow definitely needs calcium given in the vein - but did you know "giving a bottle, just in case" can actually delay her getting access to her bone stores of calcium and end up making things worse.
Have a watch of this video to explain why:
Bovikalc Bolus:
Good as a prevention for milk fever after calving in high risk animals that are still up and about, or in a milk fever case once she's treated, up and swallowing.
Price per bolus: £4.75 ex VAT
Get in touch if you're struggling with too many milk fevers, or if you want tailored advice for your set up.
HEAT STRESS - should you keep on serving?
The last few weeks of July were scorching - some of you may have seen a drop off in milk volume as heat stress kicks in, but how will those hot weeks affect fertility now and in the coming few months?
Heat stress affects fertility in a variety of ways:
Reduced bulling behaviour: during periods of heat stress, cows are less likely to show obvious heats due to reduced hormone levels - this means heats are shorter and less intense so you don't serve so many cows, and the number of negative PD at fertility visits may rise over the next few scanning visits.
Developing follicles: the decrease in hormone levels also affects the normal development of eggs - this mean there are longer follicular waves and follicles are underdeveloped if/when they do ovulate. These poorer quality eggs have a reduced chance of conception compared with normal. Don't forget it takes around 60 days for follicles to develop in the ovary from start to finish so poorer quality follicles may be filtering through over the next couple of months.
Developing sperm: heat stress affects sperm development just the same as follicles - and suppresses libido in breeding bulls too; this double whammy effect has big implications for natural service beef suckler herds.
Embryos: early embryos in the first few weeks after fertilisation are very susceptible to changes in the cows core body temperature as they don't have any heat shock proteins to protect them; in times of heat stress the cows core temperature can rise and kill off developing embryo's. Heat stress also slows the growth of the young embryo which reduces it's hormone signalling to the cow that she is pregnant and so she comes bulling instead of maintaining that pregnancy.
So, should you keep serving in a heat wave?
Yes! Stopping serving is a guarantee there will be no pregnancies and that's very rarely cost effective, but it is important for the whole team to know to expect more subtle heats and expect a few more returns after service over the next few weeks. Increasing use of synch protocols and timed AI can be helpful to guarantee ovulation and reduce the need for heat detection when cows are not showing heats as normal.
FLY SEASON
We're heading into peak fly season, and as you will all know - flies can be both costly and a nuisance to the UK’s cattle, sheep (and human!) population. In addition to the irritation caused, flies can also transmit a number of diseases, causing both financial and welfare concerns.
Fly eggs can over-winter in the soil, in undisturbed bedding or on muck heaps, and re-emerge as soon as temperatures rise above seven degrees. Once temperatures rise, female flies are prolific breeders capable of laying 3,000 eggs over their three-week lifespan. If flies are not controlled on the farm, they can produce 15 generations in one season. Adult flies that you see on and around animals only represent 15 per cent of the total population present on the farm, so it is important to act early to reduce the chance of the fly population booming.
As well as the direct irritation and stress caused by painful bites there are significant productivity losses associated with flies and external parasites on cattle, such as; reduced calf weight gain and a reduction in milk yields of up to 20 per cent (Taylor et al. 2012).
IRRITATION
The horn fly, Haematobia irritans, can feed on the blood of an animal up to 40 times a day (Bramley et al. 1985). This can lead to anaemia in calves, as well as constant irritation. It can take as few as 10 to 20 head flies, Hydrotaea irritans, per animal to have a negative economic impact on a farm (Wall and Shearer 2001) so make sure you include your calves in your fly treatment protocols.
SUMMER MASTITIS
Biting flies, such as the sheep head fly, are responsible for the transmission of the three bacteria that cause summer mastitis or "August Bag" in cattle. August Bag is a severe bacterial infection in the affected quarter, with knock on abortions in severe cases or you may see an increase in heifers calving in with blind quarters from milder, missed cases.
Make sure all grazed pregnant cattle are checked at least once a day and all staff are on high alert for the early signs of summer mastitis as we head into August. They should be looking out for animals at the back of the group, not keeping up or looking lame, with a hard, hot and swollen quarter often surrounded by flies.
PINK EYE
Face flies and the stable fly act as vectors transmitting the bacteria which cause Infectious Bovine Keratoconjunctivitis or ‘Pink Eye’. This can cause severe damage to the eye, as well as a knock-on, long-term effect on their productivity; affected calves can suffer a decrease of 17 to 18 kilograms live-weight at 205 days, when compared with healthy calves (Troutt and Schurig 1985).
BLOWFLY STRIKE
Blowfly strike is the most common ectoparasitic infestation affecting sheep in the UK: every year up to 80% of farms will report one or more cases of strike, and this equates to at least 500,000 animals affected in the national UK flock. The blowflies lay their eggs in damp or dirty wool and when the eggs hatch, it is the maggots that go on the rampage eating skin and burrowing into the deeper tissues. Toxins are released by the feeding maggots which can soon lead to toxic shock and death if left untreated.
The early signs of strike are individuals staying away from the flock, itching or nibbling at the fleece and a serious drop in appetite. Don't forget it isn't just dirty fleece that attracts blowflies, they also like infected feet.
The video below shows the typical dirty fleece of fly strike, and underneath the maggots.
A combination of cleanliness alongside topical fly treatments, fly traps, fans and parasitic wasps are often needed in combination to minimise the effect of flies on farm.
An update on our parasitic wasps
We're getting some great feedback on our parasitic wasps that we have been putting down every couple of weeks - far fewer flies in calf pens and fewer fly eggs when mucking out dry cow yards too!
Have a look at the video below to see some of our parasitic wasps in action - once they hatch they go on the hunt for fly eggs which reduces adult fly populations over time.
GET IN TOUCH:
Paula: 07764 747855 paula@haywoodfarmvets.com
Tom: 07837 291097 tom@haywoodfarmvets.com
Amy: 07507 656747 amy@haywoodfarmvets.com
Enquiries: mail@haywoodfarmvets.com
Website: haywoodfarmvets.com
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