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Goni S.,Dohne Agricultural Development Institute | Goni S.,Stellenbosch University | Muller C.J.C.,Research and Technology Development Services | Dube B.,Agricultural Research Council | And 2 more authors.
South African Journal of Animal Sciences | Year: 2015

Crossbreeding is regarded as a faster way than using pure dairy breeds to improve the reproductive performance of dairy cows, which is pivotal to farm income. The reproductive performances of Jersey and Fleckvieh × Jersey (F × J) heifers and cows were compared in a pasture-based production system. Heifers were inseminated when showing signs of heat from 13 months old and cows from 40 days post calving. Using insemination records and pregnancy check results, fertility traits were derived and compared between breeds, using analysis of variance for continuous records. Age at first insemination and conception age for heifers did not differ between the two breeds, resulting in a similar age at first calving. For cows, the mean (± SE) interval from calving to first insemination was shorter for F × J cows, being 76.7 ± 2.2 days compared with 82.4 ± 2.5 days for Jersey cows. A larger proportion of F × J cows were inseminated within 80 days post calving, compared with the Jersey cows (0.70 and 0.54, respectively). Furthermore, the proportion of cows confirmed pregnant by 100 days in milk was higher for F × J cows in comparison with Jersey cows, being 0.79 and 0.66, respectively. Although the absolute number of days between calving and conception (days open) was slightly less for F × J cows in comparison with Jersey cows (104.8 ± 6.8 and 114.8 ± 8.1 days, respectively), the difference was not significant. These results indicate the potential of improving reproductive performance of Jersey cows through crossbreeding with the dual-purpose Fleckvieh. Source


Useni B.A.,Stellenbosch University | Muller C.J.C.,Research and Technology Development Services | Cruywagen C.W.,Stellenbosch University
South African Journal of Animal Sciences | Year: 2014

The objective of the study was to determine the effect of the duration of the dry period (DP) on the milk yield and milk composition during the following lactation. Milk performance records of 561 Holstein cows, with a previous DP from the Elsenburg Research Farm obtained from the National Milk Recording Scheme, were used in the study. Four groups of dairy cows were identified, based on the duration of their dry period, i.e. cows with a DP of less than 60 days, DP of 61 to 90 days, DP of 91 to 120 days and DP of more than 121 days. The number of records for each group was 76, 162, 83 and 240 lactations, respectively. An ANOVA was conducted using the Generalized Linear Model of SAS to compare milk yield and milk composition according to the DP length. Almost 43% of cows had a DP longer than 121 days, while less than 14% of cows had a DP of less than 60 days. The milk yield was positively affected by DP length. Cows with a DP of less than 60 days produced less milk than cows with longer (more than 61 days) dry periods, e.g. 6462 ± 321 vs. 7393 ± 99 kg. Results were similar for cows in their second and fourth parity. In addition, the milk composition of cows was also affected by DP length, i.e. higher fat and protein levels in the milk from cows with a short DP. Cows in the third lactation with a DP above 121 days produced more milk than the other DP groups. However, the milk composition of cows in the third lactation was not affected by DP length. A DP of less than 60 days reduced milk yield, while an extended DP of more than 121 days would be costly for the dairy farmer even though milk yield was higher. A long dry period may also result due to an excess body condition and calving complications during the subsequent lactation. Source


Goni S.,Dohne Agricultural Development Institute | Goni S.,Stellenbosch University | Muller C.J.C.,Research and Technology Development Services | Dube B.,Stellenbosch University | Dzama K.,Stellenbosch University
Tropical Animal Health and Production | Year: 2014

Milk production parameters of purebred Jersey (J) cows and Fleckvieh × Jersey (F × J) cows in a pasture-based feeding system were compared using standard milk recording procedures. Milk, fat and protein production was adjusted to 305 days per lactation and corrected for age at calving. Effects of breed, parity, month and year were estimated for milk, fat and protein yield as well as fat and protein percentage, using the general linear model procedure. Fixed effects identified as affecting milk production parameters significantly were breed, parity and year. F × J cows produced significantly more milk than J cows (6141 ± 102 and 5398 ± 95 kg milk, respectively). Similarly, fat and protein yields were significantly higher in F × J (272 ± 4 and 201 ± 3 kg, respectively) than in Jersey cows (246 ± 3 and 194 ± 2 kg, respectively). Fat and protein percentages only differed slightly in absolute terms being 4.61 ± 0.04 % fat in the Jersey compared to 4.47 ± 0.04 % fat in the F × J. Protein levels for J and F × J cows were 3.62 ± 0.03 and 3.51 ± 0.03 %, respectively. Despite a lower fat percentage, F × J crossbred cows may be more productive than purebred Jersey cows which may be due to heterotic effects. © 2014, Springer Science+Business Media Dordrecht. Source


Swanepoel P.A.,Stellenbosch University | Swanepoel P.A.,Research and Technology Development Services | du Preez C.C.,University of the Free State | Botha P.R.,Research and Technology Development Services | Snyman H.A.,University of the Free State
African Journal of Range and Forage Science | Year: 2015

Cultivated pastures provide increased productivity and contribute inter alia to food security. Rangelands in the southern Cape region of South Africa have had a low animal production potential and were therefore improved through time as cultivated pastures. Initially, annual pastures were established by conventional tillage methods, but from the 1990s permanent pastures were established on a minimum-tillage regime. Lime and fertiliser guidelines, which were developed for annual pastures established by conventional tillage methods, were followed on minimumtillage systems, despite changes in the soil physical properties and stratification of biological parameters. The study aim was to survey the soil fertility of irrigated minimum-till kikuyu–ryegrass pastures in the southern Cape region. This study highlights changes in soil fertility and identified potential detrimental effects of elevated levels of extractable phosphorus and zinc, which were drastically increased in the topsoil layer. The necessity for remedial and preventative strategies to mitigate nutrient loading in cultivated pasture soil are stressed. Fertiliser guidelines should be applied strictly and should fit the farming system. In doing so, the dual goals of economic and ecological sustainability should be achieved. © 2015, Copyright © NISC (Pty) Ltd. Source


Swanepoel P.A.,Research and Technology Development Services | Botha P.R.,Research and Technology Development Services | Snyman H.A.,University of the Free State | du Preez C.C.,University of the Free State
African Journal of Range and Forage Science | Year: 2014

Kikuyu (Pennisetum clandestinum)–ryegrass (Lolium spp.) cultivated pastures form the base for dairy production in the southern Cape region of South Africa. The impact of various methods and implements used to over-sow ryegrass on the productivity and botanical composition of the pasture is unknown. The study aimed to assess the impact of cultivation along a soil disturbance gradient on the productivity and botanical composition of kikuyu-based pastures. Five tillage treatments were assessed, namely kikuyu over-sown with ryegrass using a minimum till planter, eradication of kikuyu with herbicide and ryegrass sown with a minimum-till planter, shallow (<150 mm) and deep (>150 mm) disturbance with a rotavator or conventional tillage, respectively, and a control. The autumn, spring, summer and annual productions of treatments with the least soil disturbance were the highest (P ≤ 0.05). Shallow or deep tillage resulted in intermediate annual productions and the lowest (P ≤ 0.05) was recorded for the herbicide treatment. Differences in production caused by different tillage methods were significant (P ≤ 0.05) and changed the botanical composition. Kikuyu over-sown with ryegrass using a mulcher and minimum-till planter was the most viable option to manage cultivated pastures. © 2014, Copyright © NISC (Pty) Ltd. Source

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