The SF rump should be reasonable large and well muscled in bulls. On the other hand we have to be cautious in propagating huge rumps because of nature’s relationship between rump size and animal size which in turn could influences the calving process. By rump size I refer to rump width („A“ in figure 15.1), rump length („B“) and pinbone width („C“). The rump and leg
bone area facilitates valuable high quality cuts like rump, silverside and topside (also called round and loin) which are illustrated in figure 18.4 (see the yellow part). Large rumps, easier calving, says who?
Often you hear a judge comment: „I prefer females with a large rump because
it gives you a wider pelvic opening and therefore calving ease.” I searched for scientific substantiation of this and actually found that wider and longer rumps are not necessarily better. What’s more, there is no relationship between external and internal pelvic size.
A few studies (1) confirm that what the judge sees from the outside is not necessarily a true indication
of what the pelvic opening will look like inside and that the actual pelvic area can only be determined by a pelvic meter. Scientists also found that in general large framed cows tend to have large pelvic areas, but also have proportionately heavier calves at birth which cancels out the effect any advantage of less calving difficulty (2) .
In an investigation on tens of thousands German SF
they compared hipbone width measurements with the calving difficulty score and found the same pattern namely all the hip width size categories had more or less the same calving ease scores. However, one would visualize that rump width measured at the pinbones is a much better gauge of calving ease than the width between the hipbones. That’s why the Germans also measured the pinbone width and simultaneously scored for calving difficulty. The percentage calving difficulty for the five evenly distributed „pinbone width groups“ will be a surprise to many experts but you can’t query accurate measurements and a scientific analysis:
Group with very narrow pinbones = 6.2 %;
Narrow = 7.3 %;
Average width = 5.8 %;
Wide = 6.2 %;
Very wide = 7.5 %.
(Data from B Luntz and LFR, Grub)
D Krogmeier analysed the EBV’s of 8400 Fleckvieh AI bulls with more than 300 000 scored progeny and found a highly positive relationship between animal size and rump length (0.68) as well as rump width (0.50) which suggests that selection for larger rumped animals will also increase animal size.
As indicated before, the key word in judging is „optimum“ and not maximum. Always follow the balanced approach and give preference to moderate sized animals which will give you medium sized rumps. Avoid assumptive unproven statements like the following (quote from a judging manual):
„The greater the width of the rump, the better. Wider rumps and hips in cows is a sign of good calving-ability and fertility, as well as early maturing and low maintenance. Wide rumps in bulls correlate to wide shoulders and shorter necks, which is indicative of masculinity.”
Should the rump be wider than long or vice versa?
I was flabbergasted to read this comment by a judge and scientist: „The rump width between the hooks should be at least six centimeters wider than the rump length from hook to pin. This is the highest indicator of fertility and femininity.” This unproven statement made me think: „Can the rump be wider than longer?”
I gathered some measurements to compare rump width and length („A“ and „B“ in Figure 15.1 according to measurements in Figure 5.2):
(I) Based on Bayern-Genetik measurements taken at a large show of mature SF dual cows (more than 2 calvings) there was no difference i.e. rump length equals rump width;
(II) I asked L Angus to measure typical mature South African SF suckler
cows in exactly the same way than the Germans did. The rumps were an immaterial 2 % wider than long;
(III) B Luntz supplied me with actual measurements of 41 000 dual SF first calving cows as well as 2000 mature dual cows. I found hardly any difference (less than 2 %) between length and width.
What are the actual measurements? The mature dual Fleckvieh show cows mentioned above have an average rump width and length of 59 cm and are 146 cm tall. In the mature suckler cows the measurement was 53 cm but bear in mind they were 10 cm smaller.
Finally, the average for the over 41 000 first calving Fleckvieh cows is 54 cm long, 55 cm wide and 143 cm tall.
Bottom line: Within two different types rump width equals rump length.
As mentioned before body parts are in proportion to each other and the same applies to external rump size i.e. a tall animal has a larger rump than a smaller one. Let measurements confirm this point within the same as well as across SF types. Since rump width and rumplength are roughly equal I refer here to „rump size“.
° In the tall dual cows men
tioned under (I) above the „rump size“ was 40 % of the cow size. This relation was just about the same for the different sizes and show classes.
° I always thought the beefier and compacter SF suckler type will proportionately have longer/ wider rumps because we breed them beefier. To my surprise the suckler animals mentioned in (II) above had almost the
same rump to cow size relation (39 %) than the dual cows although they were much smaller.
Judges must recognize that nature determines the proportion of the different body parts within the same size and the breeder cannot change that. I find it wrong when judges refer to an animal being better because it has a longer or wider part in a certain segment or area of its body than another similar sized animal.
This is the slope from hipbone to pinbone (figure 15.3) which is best quantified by the difference in height from ground to hipbone and ground to the pinbone. In dual SF it has a moderate heritability of 0.27 which is higher than rear leg and pastern set.
Rump angle is a debatable topic amongst scientists and judges. In a number of studies rump slope had
an insignificant and low correlation with (I) calving difficulty as well as (II) internal pelvic measurements (3) . This finding surprised me and I am sure a few other judges from suckler ranching countries.
Breeders in Africa prefer a definite slope from hip to the pinbones. In fact, SF judges in Africa will not place an animal with a square or flat rump. Furthermore these animals are
rejected from registration in the herdbook. The ideal rump angle in Africa is a drop of 5 10 cm from hip to pinbone. We base our policy on observations by pioneer breeders under extensive calving conditions and the fact that buffalo’s, antelope, Zebu and Sanga cattle which have no calving difficulty all have sloped rumps (Figure 15.4).
Scientist and cattle judge Maree states that „the
Figure 15.6: One issue on which all dual and beef breed judges agree is a good width between the pinbones (blue line). When well fed animals that are narrow between the pinbones often have blobs of fat next to the pinbone. The slant from hip to pinbone (red line) should not be large. (Author)
calving process is much facilitated by a sloping rump because lowered pins together with a lower position of the thurls enlarge the effective opening of the pelvis and allow more flexibility of the sacro iliac junction.” One of the worldwide greatest observers of cattle breeding Bonsma states „it is clear that, as you raise the pinbones (flat rump), you automatically narrow the opening the cow has for calving – you lessen the distance between the pelvic floor and the base of the tail.”
© P Massmann
The favoured degree of slope differs in SF countries according to SF judges I contacted: In the USA and UK they prefer square rumped animals but will tolerate a little slope. In Canada they desire a little slope but will not reject a square rumped animal at a show. Australia will not place a square rumped animal down for this reason however would prefer the sloped animal. From South America I get the message that square rumps are not acceptable. The Austrians and Germans quantify their policy by scoring 40 000 cows per year from 1 (pinbone 3 cm higher than hipbone, yes higher!) to 9 (pinbone 18 cm lower than hipbone) and their ideal score is 5 which represents a slope of 4 5 cm. As stated already, in Africa we prefer a drop of 5 to 10 cm.
The tailhead or tailroot is the beginning of the tail and consists of the first three tail
vertebrae. Because SF in general have a little higher tailroot setting than British beef breeds, SF judges are more tolerant in this regard. Actually I know many SF breeders who associate a somewhat higher tail setting with easier calving. Fundamentally a high tail setting within limits is more cosmetic than anything else. Judge M Seyfferdt maintains that a roofy rump (see figure 15.5) as well as a tucked in tail causes a loss in valuable beef.
• Roofy or droopy rump setting;
• Short rump relative to size (less than 35% of rump height or size);
• Narrow between the hipbones (less than 35% of rump height or size);
• Narrow between the pinbones;
• Markedly prominent trailhead setting;
• Wry tail setting (tail attachment off centre);
• Reverse rump tilt where the pinbone is higher than the hipbone;
• In some countries square or flat rump – require at least 5cm slope from hip to pinbone.
