Abstract
There is some indication that dry matter digestibility (DMD), fertility and peri-natal lamb survival in response to DMD may differ by breed,
which could lead to increased feeding costs that outweigh any production benefit. The aim of the current experiment was to compare the
DMD between Composite, Dorper (shedding breed) and Merino ewes using two different levels of feeding (LoF). Composite (n = 12), Dorper
(n = 12) and Merino (n = 12) ewes were fed at approximately maintenance (low) or twice maintenance (high), calculated on individual liveweight (Charles Sturt University Animal Care and Ethics Committee Protocol number A21216). Ewes were adapted to the pelleted total
mixed ration (estimate M/D = 11.2 MJ/kg DM) for 42 days prior to entering individual metabolism crates. Feed intake, urine and faces were
collected for 7 consecutive days across two periods, with half of the ewes randomly assigned to each period, balanced by breed and LoF.
Composite subsamples of faeces were dried at 80 C to constant weight. A subsample of approximately 200 g feed was dried at 80 C for
24 h. The DMD was determined as follows: ((feed DM – fecal DM)/feed DM)*100). The data was analyzed using the residual maximum likelihood technique and included breed, LoF and their interaction as fixed effects and individual pen and period as random effects. Dry matter
intake (DMI) and DMD did not differ between ewe breeds and the interaction of LoF was also not significant. Mean weight change was
6.9 kg, and +2.2 kg for ewes fed low vs high LoF, respectively. The DMD was significantly greater (P < 0.05) when ewes were fed the
low LoF (59.2 ± 0.7%) compared with the high (55.1 ± 0.8%) LoF. The significant difference in DMD was expected between LoF due to
improved efficiency at lower intake. Although there is anecdotal evidence that DMD may differ between breeds, no difference was found
in the current study. The digestibility of dry matter in dry organic matter will subsequently be determined, and metabolizable energy
intake estimated. Further investigation of urine, rumen, blood samples and weight data are required to determine if breed differences
are apparent at the physiological level.
which could lead to increased feeding costs that outweigh any production benefit. The aim of the current experiment was to compare the
DMD between Composite, Dorper (shedding breed) and Merino ewes using two different levels of feeding (LoF). Composite (n = 12), Dorper
(n = 12) and Merino (n = 12) ewes were fed at approximately maintenance (low) or twice maintenance (high), calculated on individual liveweight (Charles Sturt University Animal Care and Ethics Committee Protocol number A21216). Ewes were adapted to the pelleted total
mixed ration (estimate M/D = 11.2 MJ/kg DM) for 42 days prior to entering individual metabolism crates. Feed intake, urine and faces were
collected for 7 consecutive days across two periods, with half of the ewes randomly assigned to each period, balanced by breed and LoF.
Composite subsamples of faeces were dried at 80 C to constant weight. A subsample of approximately 200 g feed was dried at 80 C for
24 h. The DMD was determined as follows: ((feed DM – fecal DM)/feed DM)*100). The data was analyzed using the residual maximum likelihood technique and included breed, LoF and their interaction as fixed effects and individual pen and period as random effects. Dry matter
intake (DMI) and DMD did not differ between ewe breeds and the interaction of LoF was also not significant. Mean weight change was
6.9 kg, and +2.2 kg for ewes fed low vs high LoF, respectively. The DMD was significantly greater (P < 0.05) when ewes were fed the
low LoF (59.2 ± 0.7%) compared with the high (55.1 ± 0.8%) LoF. The significant difference in DMD was expected between LoF due to
improved efficiency at lower intake. Although there is anecdotal evidence that DMD may differ between breeds, no difference was found
in the current study. The digestibility of dry matter in dry organic matter will subsequently be determined, and metabolizable energy
intake estimated. Further investigation of urine, rumen, blood samples and weight data are required to determine if breed differences
are apparent at the physiological level.
| Original language | English |
|---|---|
| Pages | 613 |
| Number of pages | 1 |
| Publication status | Published - 2023 |
| Event | 11th International Symposium on the Nutrition of Herbivores 2023 - Costão do Santinho Resort, Florianopolis, Brazil Duration: 04 Jun 2023 → 08 Jun 2023 https://symposium-isnh2023.com.br/ (Symposium website) https://symposium-isnh2023.com.br/static/docs/ISNH-2023-full-programme-to-attendees.pdf (Program) https://www.sciencedirect.com/journal/animal-science-proceedings/vol/14/issue/4 (Proceedings) |
Conference
| Conference | 11th International Symposium on the Nutrition of Herbivores 2023 |
|---|---|
| Country/Territory | Brazil |
| City | Florianopolis |
| Period | 04/06/23 → 08/06/23 |
| Other | The International Symposium on Herbivore Nutrition (ISNH) addresses various issues related to herbivore nutrition in natural ecosystems or commercial production systems. It is the world's most important scientific forum on this topic, in which the nutrition of domestic and wild herbivores is discussed from the perspective of agroecology and sustainable intensification. The Symposium was held for the first time in South Africa (1983), later taking place in Australia (1987), Malaysia (1991), France (1995), the USA (1999), Mexico (2003), China (2007), UK (2011) and Australia (2014). In 2018, the 10th and last edition took place in Clermont-Ferrand, France, with ~500 participants from all continents. Unfortunately, due to the Covid-19 pandemic, the sequence of holding a symposium edition every four years has been disrupted. The ISNH is now resumed in its 11th edition in Brazil, for the first time in Latin America. The historical evolution of the different editions denotes the transition from the pure nutrition ecology of the first ones towards a more global contextualization of the role of herbivores in food security - particularly in developing countries - as well as issues related to the role of herbivores in greenhouse gas emissions, human food, and human well-being associated with the different production systems. The most recent editions have boldly expanded the spatial scale of herbivory analysis, which now ranges from the genome to the production system. The Brazilian edition intends to consolidate this evolution by focusing on Brazilian and Latin systems in an atmosphere of a broad exchange of scientific knowledge and cordiality. |
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