122
ABSTRACTS
silo should be sealed with one foot of wet weeds,straw, sawdust, or other waste material.
Spoilage may, however, be reduced to a minimum by levelling the fodder on top, tramp-
ing extremely well and wetting the surface down several times during the first week.
[J. N. W.]
A study of factors concerning herd management and herd production.
LYNN COPELAND (1939), Jour. Dairy Sci. 22, 229-39
T HE values of official production records were given as follows: (1) indicate economic
wealth of a cow, (2) furnish some information as to her transmitting ability, (3)
assist in proving both her sire and dam, (4) fat percentage and persistency of production
records are valuable for increasing the average herd test and persistency, and (5) good
records possess advertising value. Additional information obtained from the herd
average is of great value in constructive breeding work.
A study of 1046 Jersey herds under a herd test (including 27,364 cows, 12,274 of
which completed their lactations for one year), was made. Although the term ' breed-
ing efficiency ' is often used to mean the number of calves per cow per year, in this paper
the term is used in reference to the ' fraction of the year which a cow is in milk or in-
versely the percentage of the herd dry during the year '. Breeding efficiency was found
to be directly related to average production. Two figures regarding any particular
herd, it is suggested, are important: (1) average number of cows in the herd, and (2)
average number of cows in milk throughout the year. The difference between the two
gives the number of days an animal was dry during the year. The percentage of dry
cows in a herd was found to be inversely proportional to the herd average, as indicated
by a coefficient or correlation of - 0.57 ± 0.014. The average percentage of dry cows
in all herds was 14.48 per cent. The author recommends this figure as a good measure
of the comparative breeding efficiency of different herds.
It was found to be easier to maintain the breeding efficiency of small herds than
large ones. Disease control became more difficult as the size of herd increased. Regard-
less, however, of the average production of the herd, rigid culling was usually advan-
tageous.
Turner's statement that persistency of production tends to decline gradually with
age was substantiated in this study. For cows under five years, 84 per cent completed
lactations of more than 270 days. For cows from five to eight years and past nine years
the figures were 81 per cent and 77 per cent respectively. The average age of 1,582
heifers at first calving was found to be 26.49 months. This was, however, felt by Jersey
breeders to be higher than the ideal. The herd average was based on the average num-
ber (daily average for the year) of cows in the herd and not on the average number in
milk, and heifers freshening during the year milk to the end of the year, as a rule, thus
eliminating the dry period. Therefore, heifers calving for the first time during the year
did not handicap the herd average; in this study they actually helped it. [J. N. W.]
Rearing the calf. A. T. (1939), Jour. Jamaica Agric. Soc. 43 (4 & 5), 208-11
C OWS which calve in the open select for themselves a sheltered dry place and have
very little difficulty except for abnormal presentation. Cows which calve in stalls
must be provided with ample bedding and both bedding and stall must be disinfected.
The cow is broken to milk most easily if the calf is removed immediately.
There is a difference of opinion as to how long the calf might stay with the cow.
If the calf is valuable, it is best to leave it up to four or five days, otherwise it may be
removed at birth. The navel cord should be disinfected immediately after birth to
prevent infection. A good mixture for this purpose is one part of carbolic acid and
19 parts raw linseed oil. The cow should be milked regularly to prevent udder conges-
tion.
Feeding the young calf.—Because of its small stomach, the calf, if left with the cow,
gets frequent small quantities of milk at body temperature, which is desirable. Colos-
trum is laxative, high in protein and mineral matter and contains protective bodies.
New born calves should receive one quart of colostrum three times daily for four days.