Browsing by Subject "Milk production"

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The adoption potential of extended lactation as a strategy to reduce excess calf numbers in dairy farming
(2024) Gresham, Josephine; Reiber, Christoph; Chagunda, Mizeck G. G.
Dairy production relies predominantly on a few, selectively bred, high-yielding dairy breeds, resulting in a surplus of low-value male offspring. This situation leads to a conflict between a growing demand for milk and low appreciation for dairy calves. Extending lactation could reduce the number of calves born. This study aimed to assess the current use of extended lactation in dairy production in Southern Germany, identify the perceived potential, and determine the biological potential extended lactation has to reduce calf numbers. A survey from 2020 with 310 farmers was analysed. A total of 145 (46.8%) farmers used extended lactation. The use of extended lactation on farms correlated significantly with breed, milk yield, interest in continuing or implementing the use of extended lactation, and the indicated feasibility of extended lactation. The perceived potential was assessed by 39.8% of farmers as “high” to “very high”. A total of 17 (12.8%) farmers currently not using extended lactation were identified as potential adopters. Together with existing adopters, this could result in 52.3% of farms using extended lactation, which could biologically reduce calf numbers by 7.3% or 14.1% p.a., when extended by three or six months, respectively. This adoption potential shows that extended lactation can reduce calf numbers considerably, addressing both ethical and economic concerns in dairy farming and benefiting farmers as well as society.
Potential for quantifying general environmental resilience of dairy cattle in sub-Saharan Africa using deviations in milk yield
(2023) Oloo, Richard D.; Mrode, Raphael; Bennewitz, Jörn; Ekine-Dzivenu, Chinyere C.; Ojango, Julie M. K.; Gebreyohanes, Gebregziabher; Mwai, Okeyo A.; Chagunda, Mizeck G. G.
Introduction: Genetic improvement of general resilience of dairy cattle is deemed as a part of the solution to low dairy productivity and poor cattle adaptability in sub-Saharan Africa (SSA). While indicators of general resilience have been proposed and evaluated in other regions, their applicability in SSA remains unexplored. This study sought to test the viability of utilizing log-transformed variance (LnVar), autocorrelation (rauto), and skewness (Skew) of deviations in milk yield as indicators of general resilience of dairy cows performing in the tropical environment of Kenya. Methods: Test-day milk yield records of 2,670 first-parity cows performing in three distinct agroecological zones of Kenya were used. To predict expected milk yield, quantile regression was used to model lactation curve for each cow. Subsequently, resilience indicators were defined based on actual and standardized deviations of observed milk yield from the expected milk yield. The genetic parameters of these indicators were estimated, and their associations with longevity and average test-day milk yield were examined. Results: All indicators were heritable except skewness of actual and standardized deviation. The log-transformed variance of actual (LnVar1) and standardized (LnVar2) deviations had the highest heritabilities of 0.19 ± 0.04 and 0.17 ± 0.04, respectively. Auto-correlation of actual (rauto1) and standardized (rauto2) deviations had heritabilities of 0.05 ± 0.03 and 0.07 ± 0.03, respectively. Weak to moderate genetic correlations were observed among resilience indicators. Both rauto and Skew indicators had negligible genetic correlations with both longevity and average test-day milk yield. LnVar1 and LnVar2 were genetically associated with better longevity (rg = −0.47 ± 0.26 and −0.49 ± 0.26, respectively). Whereas LnVar1 suggested that resilient animals produce lower average test-day milk yield, LnVar2 revealed a genetic association between resilience and higher average test-day milk yield. Discussion: Log transformed variance of deviations in milk yield holds a significant potential as a robust resilience indicator for dairy animals performing in SSA. Moreover, standardized as opposed to actual deviations should be employed in defining resilience indicators because the resultant indicator does not inaccurately infer that low-producing animals are inherently resilient. This study offers an opportunity for enhancing the productivity of dairy cattle performing in SSA through selective breeding for resilience to environmental stressors.
Smallholder milk production in the Punjab of Pakistan and the evaluation of potential interventions
(2007) Teufel, Nils; Gall, Christian
The potential offered by milk production and marketing to increase rural income has long been recognised. Yet, milk production by smallholder households, the great majority of the 4.1 million households with dairy animals in the Punjab of Pakistan, has remained practically unchanged. In order to facilitate improved decisions on the allocation of limited development resources, this study analyses smallholder milk production, determines the effects of a variety of technical improvements and evaluates these by their household effects. For this, a linear programming model simulates household decisions based on identified objectives, recorded resources and technical characteristics. Multiple objectives are considered through compromise programming. Ten improvement scenarios are formulated. These include the introduction of new feeds (maize grain, commercial concentrates, molasses and hybrid sorghum), improved reproductive performance (reduced age at first calving and reduced inter-calving period), improved veterinary health (reduced mortality of calves and of adult females) and the introduction of genetically improved animals, through selective breeding (buffalo and cattle) or crossbreeding (cattle). Model data were collected during a cross-sectional survey of 322 randomly selected households and a 13-month longitudinal survey of 64 specifically selected smallholders in the central region of the irrigated Punjab of Pakistan. Cluster analysis identifies seven household classes in the cross-sectional sample. The three largest are considered in the model, characterised as "smallholders with marginal land resources" (class 1), "smallholders with subsistence orientated milk production" (class 2) and "smallholders with market orientated milk production" (class 3). The classification is applied to the longitudinal survey sample by discriminant analysis, identifying 9, 23, and 31 households in classes 1 to 3, respectively. Herd sizes are similar in household classes 1 and 2, with 2.1 and 2.3 adult female buffaloes respectively, while 3.6 are kept in class 3. Only 0.5 adult female cattle are kept in all classes. Land availability is similar for classes 2 and 3 (2.4 ha), but only 1.0 ha in class 1. Cropping patterns are dominated by wheat and rice. Berseem (Egyptian clover) and sorghum plus maize are important fodder crops. The nutrient supply calculated from feeding records corresponds well to estimated livestock nutrient requirements. Nevertheless, feed shortage periods in spring and early winter demand attention. Feed energy constrains livestock nutrition throughout the year in all classes. In addition to maximising family income, households also aim at maintaining their welfare against negative shocks. Also, opportunity costs of family labour are difficult to determine. Thus, maximising farm income and livestock assets (for insurance) as well as minimising loan requirements and family labour use are defined as model objectives in this order of importance. Food requirements are formulated as constraints. The activity levels produced by the base household model correspond well to longitudinal survey data. However, milk marketing is not only determined by the milk price but also by the reliability of marketing systems. Therefore, the milk price within the model is reduced to simulate recorded milk marketing levels. The price reduction is interpreted as the ?perceived? risk associated with milk marketing at village level. Model results of the ten improvement scenarios show positive effects for most interventions. Cheap high-energy feeds ("molasses", "hybrid sorghum") provide the greatest benefits for all classes. Increasing annual milk output ("inter-calving period", "selective breeding") is mainly effective in households selling substantial amounts of milk. Reducing replacement requirements ("adult mortality", "age at first calving") does not considerably improve the attractiveness of milk production. High-value concentrates (?maize grain?, ?commercial concentrates?) are unattractive as long as alternatives (e.g. wheat grain) are self-produced at current opportunity costs of land and labour. Finally, reducing calf mortality has practically no effect and crossbred cattle are only attractive under good marketing conditions with effective institutions. Including only income as objective indicates rising incomes when herd sizes are reduced in favour of cash crops. In a third model version, the effects of higher "perceived" milk prices simulate reactions to improved milk marketing. Despite considerable improvements in the adjusted base model, low-cost feeds still manage to produce considerable benefits. The study shows that introducing targeted interventions, such as providing cheap high-energy feeds, to smallholder milk production and improving market access are effective approaches for decreasing rural poverty.
The effects of rumen nitrogen balance on nutrient digestion, protein metabolism, and performance of dairy cows as influenced by diet composition
(2021) Kand, Deepashree Dilip; Dickhöfer, Uta
Feeding excess dietary crude protein (CP) beyond the requirements of dairy cattle and microbes in the rumen increases production costs for farmers, excretion of nitrogen (N) to the environment, and has negative effects on the cows’ health and reproductive performance. Researchers have been interested in exploring the effects that diets with negative rumen nitrogen balance (RNB) may have on the dairy cattle and their rumen function. Results so far have been inconsistent may be due to the performance level of the animal with high-yielding dairy cows being more sensitive than low performing ones. Moreover, it may be supposed that variable responses to negative RNB in different studies may at least partly be related to varying ingredient composition and the type of main carbohydrate or N sources in the animals’ diets. The overall objective of the thesis was to generate a comprehensive understanding on the effects of interactions between the RNB levels and carbohydrate and N sources in cattle diets on rumen fermentation, the efficiency of microbial CP synthesis, and on N use efficiency in vitro and in vivo. The results of the present thesis indicate that the effects of negative RNB levels may vary with dietary composition in dairy cows. Therefore, outlining a single minimum RNB balance threshold for dairy cattle diets may not be appropriate when optimizing N utilization in dairy cows, because several animal and dietary factors modify the requirements of rumen microbes.