CA03-5 - Helping Your Clients Maximize Health, Welfare, and Productivity in a Beef Suckler Herd

For suckler herds to run at maximum efficiency, cows should rear a calf every ____ months

12 months

What is the target bull:cow ratio for a beef suckler herd? For a young bull?

Adult: 1:50

Young bull: 1:20

What is the ideal mating period (in weeks, and in cycles) for a beef suckler herd?

9 weeks (3 cycles)

What is the ideal percentage of cows/heifers in calf at PD? 

At least 95%

What is the ideal date of first calving to date of last calving in for a beef suckler herd?

9-12 week calving period

What is the ideal rate of calving (calves born week 1:3, 1:9) in a beef suckler herd?

≥65% in first 3 weeks, ~94% by week 9

What is the ideal percentage of calves alive at 1 week old in a beef suckler herd?

≥98%

What is the ideal percentage of calves alive at weaning in a beef suckler herd?

≥98%

What is the ideal age at sale for a beef suckler herd?

12 months (bull beef) to 18 months (steers and heifers)

A fully fertile, experienced bull, will be able to achieve a ____% pregnancy rate when running with 50 normal cycling cows for nine weeks

A fully fertile, experienced bull, will be able to achieve a 90% pregnancy rate when running with 50 normal cycling cows for nine weeks

What percentage of bulls are subfertile?

20-30%

What is the main reason for culling a bull?

Lameness/poor mobility

The aim of a forage-fed bull should be to produce at least ____ calves per year and to last ____ breeding years, equating to a cost of £30/calf

At least 30 calves per year, lasting 7 years

How are EBVs used for selection of bulls?

Estimated breeding values (EBVs) that suggest genetic merit

Name some preventative measures for infectious disease upon purchase of a new bull

1. Isolate for 28 days and observed carefully for signs of infectious disease

2. Screen for BVD virus (unless from CHECS accredited free herds)

3. Source from a risk level 1 Johne’s accredited herd and if more than 2 years old, blood test for Johne’s disease antibodies

4. Screen for IBR and Leptospirosis antibodies where required. Bear in mind that many herds are either endemically infected or do not know their status for these diseases, and so should vaccinate bulls on arrival

5. Only buy ‘virgin’ bulls. Non-virgin and hired bulls are a major disease risk, especially with respect to Campylobacter fetus venerealis.

6. Treat for liver fluke if from high risk farms (check for antibody or examine a faecal sample)

7. Consider the risk of introduction of resistant Strongyle type worms and lungworm. A quarantine treatment may be required. Consider collection and analysis of faecal samples

What does a bull breeding soundness exam (BBSE) involve?

BBSEs are commonly undertaken:

• Prior/after sale

• 6-8 weeks before the breeding season – bulls that fail a BBSE are unlikely to recover prior to the breeding season (spermatogenesis takes two months), however there must be sufficient time to source a replacement bull

• When a problem is suspected e.g. after illness or at the request of an insurance company

Level 1: Physical exam - History, BCS (3-3.5), eyes, jaws, musculoskeletal, scrotum (circumference should be >32 cm by 18 mo, >34 cm by 24 mo), testes, epididymis, rectal of accessory sex glands, penis & sheath

Level 2: Physical exam + semen evaluation - can collect semen by electro-ejaculation/artificial vagina/rectal massage

Level 3: Physical exam + semen evaluation + libido/serving capacity NOTE: Level 3 exams are not commonly performed

What % of bull sperm should be progressively motile?

60%

What percentage of bull sperm should be morphologically normal?

70%

What is the difference between compensable and non-compensable defects in bull sperm?

Compensable defects are ones that can be compensated for with more sperm cells. These defects include those that don’t allow the sperm to reach the oocyte – bent tails, detached heads, coiled tails.

Non-compensable defects are those which allow the defective sperm to reach and fertilise the oocyst. They cannot be compensated for by increasing the number of sperm cells in an ejaculate – pyriform heads, nuclear vacuoles, knobbed acrosome. These defects generally have a more serious impact on a bull’s fertility

What are some general management tips about keeping a bull?

• Monitored all year and maintained at body condition 3.0-3.5

• Put out to grass (if they are to be used at grass) at least two months prior to use as dietary changes just prior to use should be avoided

• Housed in a bull pen with an exercise area when indoors

• Given regular foot care – feet should be lifted and trimmed at least annually as lameness is the single biggest problem in bulls

• Included in the herd’s vaccination and parasite control programmes

What two seasons do suckler calvings usually occur?

Spring or Autumn

Describe the spring calving BCS graph

Describe the autumn calving BCS graph

What are some tips for heifer management?

• Mate heifers with an easy calving bull for 6-7 weeks only

• PD and remove non-pregnant heifers for sale

• Feed during pregnancy for BCS 3 at calving, too fat - dystocia, too thin - extended post-partum anoestrus

• If possible, run first calvers as a separate group until pregnant again

• Think about including gestation length in breeding choices (a shorter gestation length gives a longer period in which a cow can get pregnant and remain in a 365 day calving interval). Gestation length is genetically controlled

What are some common causes of dystocia?

• Poor choice of bull badly matched to cow breed and confirmation

• Under grown heifers, and cases of misalliance

• High twinning rate (possibly associated with nutrition or genetics – poorly understood)

• Over-conditioned cows

• Under-conditioned cows (energy problems)

• Metabolic problems (hypocalcaemia or low selenium)

At what age does the suckled calf convert feed to bodyweight the most efficiently and why?

4 months old - half grass/silage/creep and half milk 

Maximizing growth in this stage is very cost effective!

From what age are beef calves weaned?

From 6 months, can be delayed to 10 months for autumn born calves for cheaper feed