The trial ran from early June 02 till end May 03; a commercial 700 cow herd located near Burnham, Canterbury was randomly halved into two sub-herds, one of which was run as per normal practice on that farm. The other sub-herd was fed an additional 0.5-1 kg Grass Seed Straw per cow per day over the trial period. The aim of this trial was to determine whether or not the addition of the extra (functional) fibre to an all grass South Island diet had an effect on the following parameters: hoof quality, clinical lameness, milksolids production, milk composition, cow condition score, cow weight, cow pasture intake, cow behaviour and rumen fill, cow locomotion score, dung consistency and cow fertility.

To this end, the soles of all right hind feet of all cows were lifted, cleaned and photographed on five different occasions during the season (August, October, December, March and May) and scored according to a modified Ohio system. Ten percent of cows out of both sub-herds were semi-permanently identified as marker cows; these cows had their front right feet scored in the same way. Clinically lame cows were identified by the herdsmen and treated by either of two members of the trial team (FH or HT), notes on cow ID and lesion location and – type and treatment were taken at the time of treatment. Milksolids production and –composition was monitored by means of monthly herd tests. Cow CS and weight were determined on 4 different occasions evenly spread over the season by AgriQuality. (NB. AQ lost the weigh data of the last session). Pasture intake was estimated weekly using a Rising Plate Meter pre- and post grazing; pre-grazing pasture samples were collected for both mobs on the same occasions. Cow’s rumen fill and grazing/chewing behaviour was assessed monthly, taking account of the marker cows only for practical reasons, 50 random dung samples of each sub-herd were scored according to a system described by Hutjens.

Locomotion scores according to Sprecher et al were performed on five different occasions evenly spread over the season. On the first occasion, this was done immediately after the cows left the crush in which they had just been foot-scored; the other four assessments took place in the same week the herd test was performed. Cow fertility: the entire herd was scanned for pregnancy in late April. Records were also kept of the subsequent calving pattern in spring 03. There are some administrative issues that still need to be resolved (mainly re-tagging of cows after the MT’s were culled in May 03) before the calving pattern can be interpreted.

The trial was marred somewhat by two factors: The normal spring feeding policy involved feeding straw/silage to all animals till September 24 th after which the trial as such started. However, low APC levels on the farm forced the farmer to feed out substantial additional amounts of high fibre straw and silage to all animals between November 14 th and December 4 th and again from March 15 th onwards (3 kg DM per cow per day as a minimum). This means that of all the hoof scoring work, only session 4 (March) the control cows were not under a protective umbrella of extra supplementary fibre; we consider the period from early January to early April to be the only “clean” interval. Pasture sample results indicated that through the entire season the NDF levels stayed over 35%, averaging around 42% NDF. This is higher than the levels (30%) at which theoretically problems can be expected to occur in the rumen leading to laminitic changes (Kolver).

In this light it is quite remarkable we did find statistically significant differences between the sub-herds at all.

Foot scores

Session 2 Control Straw s.e.d P value
Weighted erosions zone 6 (sq. Root transf.) 1.05 0.87 0.08 0.028
W. White Line Separation zone 2 0.44 0.62 0.08 0.030
W. WLS zone 2 (sq. root transf.) 0.36 0.49 0.05 0.013
Total WLS front foot 0.55 1.23 0.33 0.043
W. WLS front foot zone 2 0.23 0.55 0.16 0.048
Session 3 Control Straw s.e.d. P Value
W. WLS zone 3 1.27 1.76 0.2 0.014
W. WLS zone 3 (sq. root transf.) 0.67 0.85 0.08 0.017
Session 4 Control Straw s.e.d P Value
W. total haemorrhages zone 1+2+3 1.93 1.52 0.13 0.002
W. total haemorrhages zone 1+2+3 1.18 1.1 0.06 0.0027
W. haemorrhages zone 3. 1.53 1.23 0.1 0.0018
W. haemorrhages zone 3 (sq. Root transf.) 1.06 0.9 0.05 0.0016
W. WLS zone 3 1.92 2.44 0.25 0.032
W. WLS zone 3 (sq. root transf.) 0.87 1.07 0.09 0.022
Proportion of cows with haem. In zone 1, 2 or 3 0.795 0.727 0.0332 0.040
W. WLS front foot zone 1 0.41 0.07 0.16 0.038
W. WLS front foot zone 1 (sq. Root transf.) 0.32 0.07 0.11 0.028
W. WLS front foot zone 2 1.88 0.87 0.46 0.030
W. WLS front foot zone 2 (sq. Root transf.) 1.09 0.66 0.19 0.029
Session 5 Control Straw s.e.d P Value
W. total haem. zone 1+2+3 4.13 3.54 0.26 0.022
Total score 13.12 11.63 0.64 0.02
Total score soles only 15.98 14.35 0.81 0.045
W. Total zone 1+2+3 6.15 5.11 0.37 0.0055
W. Total zone 1+2+3 (sq. Root transf.) 2.21 2.03 0.09 0.038
W. haemorrhages zone 3. 2.46 2.14 0.14 0.025

0 = no lesion
4 = severe lesion

 

  • 1 Control cows started off with slightly more heel erosions, but difference disappeared over time.
  • 2 Straw cows started out with slightly more WLS lesions, but by the time of session 5 the difference had disappeared. In the front feet the straw cows started out with significantly more WLS lesions; by session four they had significantly less, however in session 5 there was no difference.
  • 3 Session 4 is the interesting one; theoretically this is where we should have seen the most differences. There were more haemorrhages in the entire white line (zone 1+2+3), and more haemorrhages in zone 3 in isolation.
  • 4 We assume that some of this advantage in hoof quality in session 4 has been dragged into session 5, explaining the better sole and white line quality there.

Locomotion Scores

  Control Straw s.e.d P value
Session 1 1.18 1.16 0.032 0.579
Session 1 SqRT 1.07 1.06 0.013 0.522
Session 2 1.42 1.45 0.056 0.543
Session 2 SqRT 1.17 1.17 0.021 0.700
Session 3 1.92 1.78 0.075 0.073
Session 3 SqRT 1.35 1.30 0.026 0.046
Session 4 1.81 1.59 0.072 0.0021
Session 4 SqRT 1.31 1.22 0.026 0.0011
Session 5 1.72 1.65 0.081 0.364
Session 5 SqRT 1.27 1.25 0.028 0.419

1 = normal
5 = severly lame

Comments:
No differences between straw and control until session 3; clear difference in session 4.

Condition scores

  Control Straw s.e.d. P Value
Session 1 4.3625 4.3679 0.040 0.893
Session 2 4.14796 4.11491 0.023 0.154
Session 3 4.59343 4.42638 0.035 0.0000
Session 4 4.40404 4.40653 0.029 0.932

Comments: Straw cows have a lower CS at session 3.

Cow weights

Control Straw s.e.d P value
Session 1 509,929 /td> 496.031 5.636 0.014
Session 2 508,049 499,709 4.716 0.077
Session 3 503,409 503,834 4.396 0.923
Lwt difference session 3 and 1 22.3333 28.3627 1.836 .0011

Comments:

  • 1 Straw cows start out a little lighter numerically. They catch up over the season; in fact they appear to gain weight over the season whereas the control cows appear to lose it .
  • 2 The highly significant difference in CS in session 3 is not supported by any difference in cow body weight. This could be due to either operator error in the condition-scoring, or a difference in gut fill (although all practicable steps have been taken to avoid the latter).
  • 3 Straw cows lost significantly more weight in session 3 compared to session 1 than control cows.

Cow Fertility

  Control Straw s.e.d P Value
% MT at PD 23.6252 15.90 0.031 0.013

Comments:
It appears that the straw group had less MT’s at scanning. There is still some data recovery to be done; if this is successful the subsequent calving pattern will be analysed as well. The finer details of mating performances of both sub-herds (SR’s, CR’s, CIDR use etc) have not been analysed to date.

Lame Cows, Clinical Cases

  Control Straw s.e.d P value
Clin. cases, proportion of all cows 0.175 0.16 0.028 0.612
Clin. cases 1 st Jan-1 st April 0.124 0.086 0.023 0.095
New lameness cases 1 st Jan- 1 st April. 55 39 n.a. n.a.

Comments:

  • 1 Period of 1st Jan to 1st April covers “clean interval”: starts 3-4 weeks after last whole-herd silage has been fed in December and stops 3 weeks after March whole herd silage has commenced.
  • 2 Difference in lame cows per sub-herd as a percentage of the whole herd over whole season did not reach the 5% significance level.
  • 3 Difference in lame cows as a percentage of the whole herd between Jan 1st and April comparing Straw and Control sub-herds 1st did not reach 5% significance level.
  • 4 Numerical difference of new cases between Dec 1st and April 1st comparing Straw and Control group of 55 vs 39 (29% lower in Straw group).

Dung scores

  October November December January February March
Control 1.8 1.7 1.78 1.68 1.62 2.4
Straw 1.92 2 1.72 1.84 1.74 2.32

These are numerical differences only; significance level of 5% not reached.

Milk Production

Milksolids production as per monthly herd tests.

Comments

  • 1 No significant difference in liters, but lower MP% and MF%, resulting in 3.4% less MS in the straw group. This needs to be interpreted along with the possible weight gain in the straw group and weight loss in the control group.
  • 2 Milk protein/milk fat ratios. Except for two points in the graph, milk protein/fat appears to be lower for the straw group, in line with conventional nutritional knowledge.

Some other interesting relationships have been found by relating herd tests to locomotion scores.

Locomotion Score Daily MS/cow production (kg). % Production loss % Production loss Robinson et al.
1 1.6874
2 1.6682 1 2
3 1.5567 8 4
4 1.5076 11 9
5 1.1193 34 15

 

Perhaps not surprisingly, pasture fed cows walking greater distances incur greater production losses when lame compared to housed animals.

Relating amount of pigment in soles with hoof lesions:

Session slope se slope P value
Total score vs pigment 1 -1.949 0.208 0.0000
2 -2.186 0.185 0.0000
3 -2.880 0.167 0.0000
4 -1.615 0.128 0.0000
5 -2.235 0.156 0.0000
WLS vs pigment 1 -0.176 0.057 0.0021
2 -0.187 0.047 0.0001
3 -0.287 0.056 0.0000
4 -0.269 0.065 0.0000
5 -0.148 0.053 0.0057

 

Higher amounts of black pigment in the soles are associated with higher hoof quality (lower overall score and lower WLS as well as lower sole scores, not shown). There was also a significant association between higher bodyweight and lameness incidence. It would be interesting to test the effect of breed in these associations (is it the pigment that is responsible for the better quality, or is it the breed, Jerseys being lighter and/or having darker hooves etc).

Conclusions

The trial was compromised in a number of ways beyond our control (feed shortage and pasture NDF values). Despite this, significant differences have been demonstrated between the straw-and control herds

  • 1 Horn quality benefited from a small amount of additional fibre. There was no statistically significant difference in percentage of lame cows between straw- and control cows over the period of December 1st to April 1st. Numerically, the number of clinically lame cows was lower in the straw group in that period.
  • 2 NZ pastured cows may experience larger percentage production losses compared to overseas animals when lame.
  • 3 Locomotion scores may mirror hoof quality.
  • 4 Cow in the Straw group appear to have gained BW over the season, whereas cows in the control group appear to have lost some. Cow CS changes are hard to interpret.
  • 5 Cow fertility at first glance is better in the Straw group, resulting in fewer animals diagnosed as NDP. More work needs to be undertaken on this subset of data.
  • 6 The Straw group generally had firmer dung (numerically only).
  • 7 Milksolids production is lower in the straw group; more work needs to be undertaken on these numbers.
  • 8 The use of the Milk fat/protein ratio as a predictor of cow fibre intake is supported by our findings.
  • 9 Darker hooves are associated with better hoof quality. More work needs to be done here: breed/cow weight interference, pigment vs clinically lame cows etc.

We would like to thank our sponsors, Dairy Insight, Intelact and Veehof Professional for their support of this trial.

Helwi Tacoma

Wybe Kuperus

Fred Hoekstra

Marius Troost

Wybe Fokkink