AVERAGE PERIOD FOUND.

Ashburton Guardian, Volume 59, Issue 20, 3 November 1938, Page 8

AVERAGE PERIOD FOUND.

CALVING RECORDS

difference IN SEXES. Au investigation into the calving records of the tuberculin-tested herd of dairy coavs at the Lord Wandsworth Agricultural College (England) was prompted by the suggestion that hull calves ahvays tend to go long over time. Apparently this impression is more apparent than real. A period of ,1 ’ years between July, 1933, and February, 1938, js covered by this investigation, and during this time 150 calves were born, no account being taken of abortions.

The milk Recording Society’s period for gestation of 281 days has always been used on this farm for calculating probable calving dates, but it appears that this period is too short, the average of 150 calves being 284 J days. The average gestation period for hull calves Avhich accounted for 54 per cent of the total births, Avas 285 days, one day longer than .the average heifer calves. Although, therefore, the difference betAveen the sexes is small, nevertheless it should be mentioned that Avhereas in 14 instances bull calves were bom 10 days or more beyond the expected time, in only a single instance did this occur Avith a heifer calf. The five Avinter months, October-Feb-ruary inclusive, yielded 60 per cent of the total births, with January the most prolific month in the year. This would, apparently, suggest that matings made in the months February to June inclusive are the most likely to succeed for such an uneven incidence of calvings is not intentionally planned. Fewest births occurred in March and April. Although births Avere most numerous during the Av.inter months, it Avas also found that the pregnancy period Avas prolonged, as the average gestation periods slioav :

hi the autumn of 1934 the adultdairy stock Avas very severely affected with husk. During this period 13 births were recorded, of Avhich five took place on the average—three days earlier than expected indicating the adverse effect of continual coughing in the heavily pregnant coav. The records of individual coavs were examined to see Avhether any animals sluiAved a tendency to’produce only bull calves or vice versa, but there was no definite evidence of this. There was also no evidence that an animal Avhich “goes over time” does so Avith regularity at every calving.

November . • • . . . 285.7 clays December . • . . . '287.2 days January . . . 285.4 days February . • • . . 284.8 days