Othman Alqaisi

In the global dairy production sector, feed ingredient price and availability are highly volatile; they may shape the composition of the feed ration and, in consequence, impact feed cost and enteric methane (CH₄) emissions. The objective of this study is to explore the impact of changes in feed ingredients’ prices and feed ingredients’ availability on dairy ration composition, feed cost and predicted methane yield under different levels of milk production. To meet the research aim, a series of multi-period linear programming models were developed. The models were then used to simulate 14 feed rations formulations, each covering 162 months and three dairy production levels of 10, 25 and 35 kg milk/d, representing a total of 6804 feed rations altogether. Across milk production levels, the inclusion of alfalfa hay into the feed rations declined from 55% to 38% when daily milk production increased from 10 to 35 kg, reflecting the cows’ increased energy requirements. At a daily milk production level of 35 kg, CH₄ production (per kg milk) was 21% and 53% lower than in average and low milk producing cows, respectively, whereas at 10 kg of milk production the potential to reduce CH₄ production varied between 0.6% and 5.5% (average = 3.9%). At all production levels, a reduction in CH₄ output was associated with an increase in feed costs. Overall, and considering feeding scenarios in low milk producing cows, feed cost per kg milk was 30% and 37% higher compared to that of average and high milk production, respectively. The feed ration modeling approach allows us to account for the interaction between feed ingredients over time, taking into consideration volatile global feed prices. Overall, the model provides a decision-making tool to improve the use of feed resources in the dairy sector.

The objective of this study was to investigate the effect of feeding high and low concentrate diets on feed intake and feed efficiency, the morphological characteristics of the rumen papillae, and meat quality of Holstein steers fattened under hot climate conditions in Oman. Ten male Holstein calves, of 5 months of age, were selected for the experiment. The animals were fed concentrate and Rhodes grass hay and were divided into two groups of high concentrate (HC, n = 5) and low concentrate diets (LC, n = 5), in which their feed intake, weight gain, and feed efficiency were evaluated across three growing periods. Feed intake and efficiency and average daily gain (ADG) of the HC group were significantly greater than for the LC group and were affected by the diet ( p < .01) and the period ( p < .001). Across the fattening periods, ADG declined in both groups, with ADG improved by 35% for steers on the HC diet compared to steers on the LC diet. Carcass meat quality was not affected significantly by the dietary concentrate level. In conclusion, our results can be used to make improvements in feed efficiency of Holstein steers under hot climate conditions.

The aim of this study was to evaluate the effect of diet and animal shearing on the feed and nutrient intakes, water intake, in vitro ruminal methane production, and blood parameters of Omani sheep. A pens trial was carried out for 16 days each in March and June of 2017 using 20 Omani non-castrated yearling rams selected from the sheep herd in the research station and randomly assigned to four groups with 5 animals per group. Group 1: sheared animals fed a high concentrate (HC) diet, group 2: fleeced animals fed a HC diet, group 3: sheared animals fed a low concentrate (LC) diet, group 4: fleeced animals fed a LC diet. Furthermore, a metabolic crates trial was carried out in July of 2017 on three animals from each group over a 10-day period. The effect of diet and shearing on the tested parameters was evaluated using the mixed linear model, where animals were fitted as a random effect to account for the individual animal deviation from the overall mean. Results showed that rams fed on the high concentrate diet had a significantly increased organic matter intake of the total diet (62 g/kg ^0.75 Live Weight (LW) in HC group to 54 g/kg ^0.75 LW in LC group), an increased water intake (6.3 L/day vs 4.8 L/day in LC group), and a reduced in vitro methane production (i.e. the invitro ruminal CH₄ was measured and converted to daily CH₄ using the daily feed intake data and was 20.4 g CH₄ per head/day in HC group vs 27.3 g CH₄ per head/day in LC group), compared with rams fed on the low concentrate diet. Furthermore, shearing had a significant effect (P < 0.01) on increased feed and nutrients intake. The apparent and organic matter digestibility was significantly different (P < 0.01) between the experimental groups and was greater for those rams fed on the HC diet. Partial substitution of low-quality Rhodes grass hay by high-quality concentrate significantly improved the total diet organic matter digestibility (P < 0.01) and nutrients digestibility, whereas no significant effects on biochemical blood parameters or animal health were observed. These results show the importance of utilizing effective feeding and shearing plans to improve the productivity and reduce the methane emission of Omani sheep.

Data of milk production and performance under Oman climatic conditions are limited. The current study presents a 9-year analysis of daily milk performance of Holstein and Jersey cattle breeds born and raised in Oman and fed similar diets of concentrate and Rhodes grass hay. Data on the daily cow’s milk production, during the entire lactation period for nine consecutive milking years between 2009 and 2018, were collected. The data was introduced to a linear mixed model and was analyzed to evaluate the breed variations in milk production across lactations and across years. Holstein Friesian (HF) cows had significantly (P < 0.001) higher daily milk production of 17.6 ± 0.4 kg/cow/day compared to 11.7 ± 0.8 kg/cow/day for Jersey cows. Across years, we observed a gradual annual improvement in total milk production in both HF and Jersey breeds of 5% and 6%, respectively. The highest daily milk production was in the third and fourth lactations for HF cows and in the second and third lactations for Jersey cows. In a region where much of the expected demand in milk will be met by exotic breeds and importation, our results provide an insight into the performance of temperate breeds in hot and arid climatic conditions. As such, our results shall be useful for dairy producers seeking to maximize milk production under such conditions.

Objective: The aim of this study was to evaluate the effect of thermally processed Prosopis juliflora pods (PJP) on the growth performance of broiler chickens. Methodology: Two experiments were conducted. In experiment 1, the nutritive value of raw or thermally processed PJP was evaluated through an ileal digestibility assay. Apparent metabolizable energy (AME) and ileal digestibility of crude fibre in the formulated diet (corn, raw and thermally processed PJP) were determined. The second experiment (a growth study) was designed to test the effect of thermal processing on the nutritive value of PJP (p<0.001). Seven dietary treatments were evaluated in experiment 2, namely, the basal diet, three levels of inclusion of raw PJP-based diets (5, 10 and 15%) and three levels of inclusion of processed PJP-based diets (5, 10 and 15%). Results: The results of experiment 1 showed that the AME of processed PJP was higher (24%) than that of raw PJP. The raw PJP had significantly lower AME content (10.16 vs 13.41 and 15.26 MJ kg–1) and lower apparent ileal digestibility coefficients of crude fibre (0.27 vs 0.46-0.65) compared to processed PJP and corn, respectively (p<0.001). The results of experiment 2, indicated that substitution of corn by 10% processed PJP significantly improved the crude fibre digestibility and AME (p<0.001) compared to the other dietary treatments. The weight gain of birds fed 10% processed PJP (55.13 g/bird/day) was similar to those of birds fed a basal diet (55.68 g/bird/day). Conclusion: Processed PJP can replace corn up to the level of 10% in broilers diets without affecting growth performance.