Optimised dairy cow feeding economy in Hungary

High yielder cows optimal feeding is always a major question in farm management. We attempted to find the optimal yield- and weight group in a Holstein_Freisian herd. Handled more than 2000 milk record samples and concluded that the optimal body weight is about 600-650 kg. Also step up from medium yielder to high yielder is more cost efficient than pushing the milk production over 30 kg milk daily. Our results show that fitness traits and body scores are major factors and every 50 kg of extra weight rises the forage cost in average of 0,11 €cents. The mid-weight cows produce 25 kg of milk daily but the herds are very heterogeneous. The solution should be smaller cows, homogeneous herds and optimized feeding.

Selection for longevity and yield in dairy cows using transmitting abilities for type and yield

A dynamic programming model was used to derive economic values for the goal traits milk, fat and protein yield and longevity. The economic values derived were £3.37 per % cows surviving to complete lactation four (conditional on having a milk record in the first lactation) and £-0.03, £0.60 and £4.04 per kg for milk, fat and protein yield respectively. In terms of genetic standard deviations the weight for protein, fat, milk and longevity were 1.0, 0.21, —0.25 and 0.55, respectively. Using economic values and genetic (co) variances, weights were derived for milk fat, protein and four linear type traits (chosen out of fifteen on the basis of the genetic correlation with longevity): angularity (angular), foot angle (steeper), udder depth (shallower) and teat length (shorter). Three additive indices were derived, assuming that the breeding goal was for: (i) yield only (PIN), (ii) longevity only (LIN) or (ii) yield and longevity, hence economic merit (ITEM). Selection on ITEM is expected to give a 2% higher annual rate of genetic progress compared with selection on PIN. Efficiency of using ITEM was larger than 0.97 compared with the optimum index, when the real individual economic values increased or decreased by a factor 1.5 or 2.0. Weights for ITEM were calculated assuming that predicted transmitting abilities (PTAs) from complete multivariate analysis were used as index measurements. In the practical situation that index measurements came from (i) separate univariate best linear unbiased prediction (BLUP) evaluations or (ii) two multivariate BLUP evaluations (one for type and one for yield), efficiency of ITEM (compared with the optimum index) decreased with decreasing accuracy of the PTAs and with increasing ratio between number of records for type and yield, or vice versa, but remained close to 100%. Only in the (not practical) situation where accurate PTAs for type and inaccurate information for yield were combined, did the efficiency of ITEM drop as low as 0.44, due to a change of sign for udder depth in the optimal index.

Decline in Milk Yield from the East to the West

It is very well known that milk records show a considerable downward trend in yield from the East to the West of England and Wales. The Bureau of Records of the Milk Marketing Board have produced some admirable maps, shaded by counties according to the average yield, and these bring out the trend very clearly ; roughly the yield declines from 730 to 630 gallons, a drop of 15 per cent. This trend in yield is not a new phenomenon. Twenty-five years ago Dr. Hammond and I found the same thing with 26 counties which by 1923 had had milk recording societies functioning for five years ; the decline was approximately from 700 to 600 gallons. We selected two societies which were at that time about at the extremes and extracted lactation figures from the milk record books of the members in an effort to probe a little deeper into the difference. I hope to refer to these two again and will only say now that Norfolk milk recorded cows gave 22.8 per cent, more milk than those of Penrith, and of this difference, 6 per cent, was due to higher yield at the start of the lactation and the rest to greater persistence of yield and to longer continued milk flow.