ABSTRACTS
325
and these, as a result of heterozygosis, produce a very considerable number of secondary
characters. This is responsible for the multiple characters of our domestic animals, as
well as the genotypical varieties of wild animals. When, however, by chance, two in-
dividuals, possessing between them every one of the original components, unite, they
reproduce the primitive character (e.g. the appearance of the characteristic coat of the
wild rabbit following crossing between two subjects, neither of which showed in themselves
any wild characters).
Real atavism is only manifes ed through hereditary characters, maintained through
generations of beings more or less heterozygous. Atavism of acquired characters (non-
genotypical) is transitory and ceases to exist when the possibility of acquiring them dis-
appears. [J. F. S.]
Differentiation between the sheep and the goat in supervised Senegalese
Abattoirs (Differenciation de la Chevre at du Mouton dans les Abattoirs
surveilles du Senegal). R-. LARRAT and LAMINE DIAGNE (DAKAR). Bull. Ser.
Zoo. et Epizoo. de l'Afrique Occident 2, iv pp. 19-23.
T HE anatomical and physical distinctions between sheep and goats is commercially
less important in French East Africa than in other countries. Lack of selective
breeding has led to convergence towards a single intermediate type of animal. This
complicates the work of meat inspectors.
The complete carcass provides an insufficient basis for differentiation and frequent
errors are made, even when a comparative study is made of sheep and goat carcasses
placed side by side.
The problem commonly resolves itself, not into differentiation between the two
species, but into distinguishing between the two morphologically comparable long bodied
kinds of sheep and goats [(a) the sheep of the Mauritanian and Soudanese Sahel, (b) the
' Maure ' goat] and the two medium bodied varieties [(a) the short, thickset sheep, (b) the
goat of the Senegalese and Soudanese Savanna].
Anatomical signs, described in classic treatises for determining the differences
between the two species of animals, are only of limited value here, since there is
displayed the whole gamut of intermediate signs between the two species.
Physical characteristics such as the flesh, fat, smell and skin equally provide an
uncertain basis for distinction.
The only certain indication upon which the meat inspector can, and should, depend,
in Senegal, to distinguish sheep from goats is the presence or absence of the supracostal
scalene. In the case of medium bodied sheep and goats, one may also add the curvature
of the sternum. All other characters said to be distinctive have only a relative value
[J. F. S.].
Comparative value of Napier and Sudan grass when used as soiling crops
for dairy cows. L. H. HENKE and G. W. H. Goo (1939). J. Dairy. Sci. 22,
1007-1010.
I N regions remote from Honolulu, cattle graze the year around; near the city, how-
ever, they receive their roughage from soiling crops fed green. Concentrates are
added. Napier grass (Pennisetum purpureum) and Sudan grass (Sorghum vulgare suda-
nense) are commonly used. This study compares them as soiling crops for milking cows.
A four week reversal system of feeding was used in four 12-week trials, three with six
and one with eight cows ; two lots were made in each case on the basis of milk production,
body weight, age, days after calving and expected freshing date. Advanced pregnancy
was avoided. Data from the first week in each of three 4-week periods within each trial
were not considered ; this week was allowed for changes of feed. In the first two trials
the roughage was fed without chopping, whereas it was put through a silage cutter before
being fed in the last two. Daily samples of green fodder and orts were taken and moisture
was determined. Composites for each three week experimental period were used for crude
protein, ether extract, nitrogen-free extract, fibre and ash determinations. On the basis
of the Morrison Standard ample protein and total nutrients were provided to all animals
whether Napier or Sudan grass was fed. The animals were kept in small paddocks.