Crossbreeding data involving Ghana Shorthorn, Sokoto Gudali and their Jersey F1s and backcrosses collected over a 16-year period were analysed to estimate additive and heterotic effects for milk production, reproduction and calf growth traits. Sokoto Gudali was significantly better than Ghana Shorthorn in all milk production traits. Calving interval and annualized milk production were better in Gudali than in the Shorthorn. The F1s had higher lactation milk yield, milked longer, produced their first calves earlier and had shorter dry periods and calving intervals than their corresponding purebreds. However, genotype was not significant for number of services per conception. Both F1s had higher average daily gain and weaning weight than their corresponding purebreds. Sokoto Gudali backcross (Jersey × F1) was significantly (P < 0·05) better than the F1 in lactation length. However, in Gudali crosses, there was no advantage in increasing the proportion of Jersey genes beyond 0·5 for milk production traits. Additive effects were significantly (at least P < 0·05) lower in the Shorthorn and the Gudali than in Jersey for milk production traits except proportion of butterfat. Heterosis estimates were significant (P < 0·01) for milk production traits for the Shorthorn but not for the Gudali. Heterotic effects were large and significant (at least P < 0·05) in improving annualized milk production in Shorthorn crosses, whilst none of the heterotic effects for reproductive traits was significant. At both 0 and 0·5 levels of Jersey inheritance, the Gudali was superior (P < 0·01) to the Shorthorn in birth weight, weaning weight and pre-weaning average daily gain. Heterotic effects for calf traits were positive and much larger in Gudali crosses than in Shorthorn crosses. In general, backcrosses were, at best, similar to the F1s implying that upgrading these indigenous breeds beyond 0·5 European inheritance may not be desirable.

An experiment was conducted to investigate the effect of concentrations of certain blood nutrientsensitive metabolites and the resumption of postpartum ovarian cyclicity in 16 Sanga cows (mean BCS 5). Blood samples were taken from cows from weeks 1 to 13 (90 days) postpartum, processed and the plasma progesterone concentration measured to determine the resumption of postpartum ovarian cyclicity. The cows were classified as having resumed ovarian cyclicity when a plasma progesterone concentration of ≥1.0 ng/mL was recorded for two consecutive weekly samples. Based on the resumption of ovarian activity, cows were classified as early cycling, late cycling or non-cycling. The plasma glucose, cholesterol, total protein, albumin and globulin concentrations recorded were similar in the early cycling, late cycling and non-cycling cows. The mean blood glucose, cholesterol, total protein, albumin and globulin concentrations were 3.60 mmol/L, 2.47 mmol/L, 83.1 g/L, 29.9 g/L and 52.9 g/L, respectively. Plasma urea concentrations in late (6.57 ± 0.17 mmol/L) and non-cycling (6.59 ± 0.17 mmol/L) cows were higher than in the early cycling (5.99 ± 0.17 mmol/L) cows in weeks 1 to 13 postpartum. In addition, the plasma creatinine concentration in the early cycling cows was higher than in late cycling cows (101.8 ± 1.82 versus 94.0 ± 1.99 mmol/L). Cows with higher plasma concentrations of urea and lower creatinine concentrations were at risk of delayed resumption of postpartum ovarian cyclicity. Results suggest poor nutritional status, especially energy deficiency, as a major underlying factor suppressing the postpartum resumption of ovarian cyclicity.

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A study was made of some aspects of reproduction in the Nungua Black Head and the Ghanian variety of the West African Dwarf sheep. The gestation period of the two breeds was similar: 150 and 148 days respectively. Ewes mated in August and September tended to have slightly longer gestation periods than those mated in March. The mean birth weights were 2-2 kg in the Nungua Black Head and 13 kg in the West African Dwarf. Type of birth affected the weight of lambs at birth. The Nungua Black Head had no triplets, 0132 twins and 0-868 singles. The West African Dwarf was more prolific: 0-402 singles, 0-557 twins and 0041 triplets. The weight advantage of the Nungua Black Head lambs at birth was maintained to weaning and they also had better survival rates. The adjusted 12-week weaning weights averaged 9-8 and 5-8 kg respectively for the Nungua Black Head and West African Dwarf. What the West African Dwarf lost in individual weight it appeared to make up in numbers so that, when the breeds were compared in terms of kg of lamb weaned per ewe mated, there was no significant difference between them.

Calf records on 621 West African Shorthorn (WASH) and 3 grades of Jersey x WASH crossbreds were analysed for the effects of the level of Jersey breeding and other factors on birth weight, 205-day weaning weight and average daily gain (ADG). Crossbred calves were significantly (P < 0.01) heavier at birth than purebred WASH and birth weights increased with increasing level of Jersey breeding. No significant differences were established for 205-day weaning weight, however ADG declined with increasing level of Jersey breeding suggesting possible problems of adaptation for calves of over 75% Jersey breeding. Age of dam effect was significant and linear (P < 0.0001) for birth weight and significant and quadratic (P < 0.01) for weaning weight and ADG, with values increasing from 3-year old dams to a peak in 7 year old dams.

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The study was conducted to estimate relative economic values (REVs) of survival, body weight, growth rate, reproduction, docility and food intake. Data were obtained from records of grasscutters (Thryonomys swinderianus) kept at the grasscutter section of the Department of Animal Science Education, University of Education, Winneba, Ghana. Average values of production inputs and outputs parameters were computed from records of 502 kids born between 2006 and 2010. Relative economic values of traits were computed by using computer models in Microsoft Excel spreadsheet of Windows 2007. When feed intake was included in the breeding objective and economic evaluation was based on genetic standard deviation, mature body weight emerged as the most important trait. Ranking order of traits was body weight > survival > reproduction > growth rate > feed intake > docility. The ranking order was maintained when feed cost was set to zero. The use of coefficient of variation to estimate REVs changed the ranking order of traits: Growth rate > reproduction > docility > survival > body weight > feed intake. It was concluded that post-weaning growth rate, litter size at weaning and docility should be selected to be included in the breeding objective of grasscutter breeding programmes in Ghana.