Journals

A technique is described which allows automatic collection of jugular venous blood from tethered cows. In this system, blood is pumped continuously from an intravenous cannula which has a double lumen while an anticoagulant is pumped through the second opening…

Eighty Dohne Merino lambs were divided into 4 groups to investigate the effect of different succulent feeds and concentrates given to ewes and lambs on veld grazing. From the time of lambing ewes received the following supplementary rations per head…

Dorper and Blackhead Persian ewes and ewe lambs were grazed on veld during the day and fed varying amounts of cottonseed meal when kraaled at night. The teeth were examined weekly when the sheep were weighed and eruption of permanent…

Since stress has been shown to influence prolactin release in sheep, the secretion of this hormone during the oestrous cycle of the ewe was re-evaluated. At intervals of two hours, for a total period of 40 hours, blood samples were…

The pattern of luteinizing hormone (LH) and prolactin release following the synchronisation of oestrus with progesterone or SC-9880 was studied. Of the 10 ewes treated with progesterone three did not exhibit oestrus. Where oestrus was synchronised with SC-9880 the preovulatory…

Three experiments were conducted to examine the effects of dilution rates prefreezing and at thawing, pellet volume, and of thawing temperature on the survival and acrosome-morphology of ram spermatozoa. Semen was diluted with a Tris-giucose diluent and frozen in pellet…

Five factorial experiments were conducted to examine the effects of different freezing methods on the survival of ram spermatozoa following the freeze-thawing procedures Semen was frozen in pellet form and in straws on either dry ice or in liquid nitrogen…

Karakul ram lambs were divided into three groups after weaning and treated as follows: Group A: Total isolation; Group B: Contact with ewes until 9 months and then isolated; Group C: Isolated from ewes until 9 months and then allowed…

Directly after calving 62 Bonsmara cows were divided into one of the following groups: Group A served as a control and calves were allowed to remain with the cows and weaned at 7 months. In groups B, C and D…

The incidence of oestrus, ovulation. fertilisation and embryonic mortality were investigated in a series of experiments. In the first experiment, the occurrence of oestrus and ovulation in Africanders and Hereford cows were compared. It was found that Africanders showed oestrus…

Beef  production with the Jersey dam as basis.  1. The production potential of jersey cows under extensive conditions During a five year period, an average of 87 Jersey cows and heifers were evaluated for the production of weaners under extensive…

Beef production with the Jersey dam as basis: 2.The production potential of various crossbred Jersey progeny: Two hundred and twenty nine crossbred Jersey calves from Africander, Charolais and Hereford bulls were produced and evaluated as slaughter animals over a four…