Kruisteling met afrikanermoer as basis: 1. dragtigheidsduurte, geboortemassa en die voorkoms van distokie by die nageslag van verskillende rasse van vaars

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Hormone levels in peripheral plasma of the Afrikaner cow II. Progesterone and total unconjugated oestrogen levels during late gestation and parturition

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Waarnemings oor die voorkoms van bronstigheid by Afrikaner en Jerseykoeie onder ekstensiewe toestande in Noord-Kaapland

Gedurende die uitvoering van twee kruisteeltprojekte te Vaalhartslandbounavorsingstasie is inligting verkry in verband met die voorkoms van bronstigheid tydens 'n geslote dekseisoen by Afrikaner- en Jerseykoeie. Vir vyf agtereenvolgende jare is waarnemings gedoen op 'n kudde van ongeveer 270 Afrikaner en 75 Jerseykoeie. Oor genoemde periode het uit 'n totaal van 1297 Afrikaner- en 357 Jerseykoeie, 80,3 en 94.7% onderskeidelik waarneembare estrus getoon. Dit was veral lakterende Afrikanerkoeie en by uitstek die met hul eerste kalf wat geneig het tot 'n lang post partum anestrusperiode. Slegs 55,9 %van laasgenoemde groep het tydens die dekseisoen waarneembare estrus getoon teenoor 86.2% by dieselfde groep Jerseys. Die Jerseykudde is egter van 'n energielek voorsien gedurende kritieke voedingstoestande wat wel 'n effek kon gehad het. Afrikaners het 60.3 %van die waargenome bronsperiodes in die vroee oggend getoon teenoor 39,7 %in die laat namiddag. Ooreenstemmende data by die Jersey was 59,0 en 41,0%onderskeidelik vir die twee waarnemingstye, Van 543 voltooide estrussiklusse by die Afrikaner was 57,1 %binne die normalc grense (18 -23 dae) teenoor 53,6 %van 194 siklusse by die Jerseys. Siklusse korter as 18 dae het in 22.1 % van die gevalle by die Afrikaner voorgekom teenoor 32,5 %by die Jerseys. Die gemiddelde lengte van normale siklusse was 20,53 en 20.35 dae by die Afrikaner en Jersey onderskeidelik.English Title: Observations on the occurrence of oestrus in Africander and Jersey cattle under extensive conditions in the Northern CapeEnglish AbstractData concerning the occurrence of oestrus in Africander and Jersey cattle under extensive conditions were obtained from a crossbreeding program at Vaalharts Agricultural Research Station. Observations were made during the annual two and a half month breeding season on a herd of approximately 270 Africander and 75 Jersey cattle for five consecutive years. During this period oestrus was observed in 80,3 % of 1297 Africander and in 94,7 % of 357 Jersey cows. The occurrence of a relatively long post partum anoestrous period was evident in lactating Africander cows, especially those with the first calf at foot. Only 55,9 %of the latter exhibited oestrus during the breeding season compared to 86,2 %of their Jersey counterparts. The Jersey herd, however, received an energy lick during critical nutritional periods which may have had some effects. Amongst the Africanders, 60,3 % of the observed oestrous periods were first noted during the early morning and 39,7 % in the late afternoon. The corresponding percentages for the Jersey females were 59,0 and 41,0 %respectively. Of the 543 completed oestrous cycles recorded in the Africander herd, 57,1 % were within the normal acceptable limits (18-23 days) as against 53,6 %of the 194 completed cycles of the Jerseys. A cycle length of less than 18 days was recorded in 22,1 and 32,5 % of the observations amongst the Africanders and Jerseys respectively. The average length of normal oestrous cycles was 20,53 days in the Africander against 20,35 days in the Jersey

Hormone levels in peripheral plasma of the Afrikaner cow I. Progesterone and luteinizing hormone levels during the oestrous cycle

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Estrussinchronisasie by Afrikanerkoeie buite die normale teelseisoen

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The effect of treatment with a slow-releasing oxytocin preparation at the onset of oestrus on the ovulation rate of Merino ewes : research note

The effect of a slow-releasing oxytocin preparation on the ovulation rate of Merino ewes was investigated. Synchronised Merino ewes were subcutaneously injected with a slow-re-leasing preparation containing 10 IU oxytocin, 48 hours after sponge withdrawal. Laparo-scopic examination of the ovaries of all ewes was performed 10 d after the oxytocin treatment in order to determine the number of corpora lutea per ewe. The ovulation rate of the adult ewes of the treated and control groups was 179.1 % and 159.1 % respectively (p 0.05). It would appear that a higher ovulation rate can be obtained by a single injection of a slow-releasing oxytocin preparation at the onset of oestrus. The lack of response in the 2-tooth ewes was probably due to their relatively low body weight

Vleisproduksie met die Jerseymoer as basis. 1. Die produksiepotensiaal van Jerseykoeie onder ekstensiewe toestande

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Effect of oxytocin treatment during oestrus on the ovulation rate of Merino ewes

The effect of oxytocin treatment on the ovulation rate of Merino ewes was investigated, intravenous doses (0.1 IU) of oxytocin were administered to synchronised ewes (n = 54) every 30 min for a 24 h period beginning at the onset of oestrus. Laparoscopic examination of the ovaries of all ewes, that had displayed overt oestrus following sponge withdrawal was performed 10 d after the beginning of oxytocin treatment to determine the number of corpora lutea per ewe. The ovulation rates of the treated and control groups were 174.5% and 144%, respectively (p < 0.01). It would appear that a higher ovulation rate can be obtained by repeated low-dose intravenous injection of oxytocin during oestrus.Articl

The effect of treatment with a slow-releasing oxytocin preparation at the onset of oestrus on the ovulation rate of Merino ewes

The effect of a slow-releasing oxytocin preparation on the ovulation rate of Merino ewes was investigated. Synchronised Merino ewes were subcutaneously injected with a slow-releasing preparation containing 10 IU oxytocin, 48 hours after sponge withdrawal. Laparoscopic examination of the ovaries of all ewes was performed 10 d after the oxytocin treatment in order to determine the number of corpora lutea per ewe. The ovulation rate of the adult ewes of the treated and control groups was 179.1% and 159.1% respectively (p 0.05). It would appear that a higher ovulation rate can be obtained by a single injection of a slow-releasing oxytocin preparation at the onset of oestrus. The lack of response in the 2-tooth ewes was probably due to their relatively low body weight.Articl

Crossbreeding with Africander dam as basis. 2. Weaning performance of progeny of various sire breeds

Weaning mass was studied for 753 calves out of Africander cows by Africander, Brahman, Charolais, Hereford and Simmental sires. Crossbreds performed 11.1 per cent to 11.8 per cent better than Africander controls. Charolais progeny had a significantly greater weaning mass than Hereford and Simmentaler progeny with Brahman progeny in an intermediate position. When all cases of dystocia were taken into consideration, however, the net weaning mass output per cow calved for Simmental, Brahman and Hereford bulls was considerably better than that for Charolais and Africander bulls