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Ammonium dipropionate in the total mixed ration does not change the ingestive behavior but improves the productive performance of feedlot bulls

Abstract

The objective of the present study was to evaluate the productive performance, the ingestive behavior, the apparent digestibility of the diet, and the carcass characteristics of beef steers finished in confinement under the effect of ammonium dipropionate in the diet, and the fractionation or not in the supply of the diet. The experimental design was completely randomized, in a 2 x 2 factorial scheme, totaling four treatments, as follows: Diet without ammonium dipropionate provided twice a day; Diet without ammonium dipropionate given once daily; Diet with ammonium dipropionate provided twice daily; Ammonium dipropionate diet provided once daily. Thirty-two ½ Angus ½ Nellore bulls were used, with an average age of 11 months. The use of ammonium dipropionate in the overall average increased average daily gain, dry matter intake, and carcass gain. The diet provided twice a day provided, on average, greater weight gain, greater carcass gain, and better feed conversion. When evaluating the association between treatments, the use of dipropionate plus the diet supplied twice a day showed greater daily carcass gain during the experimental period and higher hot carcass weight (1.251 kg, 111.4 kg, and 308.6 kg respectively), as well as ensuring better apparent digestibility of dry matter (74.57%). With the data obtained in the present study, it is possible to state that it is advisable to use ammonium dipropionate while maintaining the fractionation of the diet for beef steers in the finishing phase.

Keywords:
animal performance; carcass characteristics; chemical stabilizer; diet digestibility; feed management

Resumo

O objetivo do presente estudo foi avaliar o desempenho produtivo, o comportamento ingestivo, a digestibilidade aparente da dieta e as características de carcaça de novilhos de corte terminados em confinamento sob efeito do dipropionato de amônio na dieta, e do fracionamento ou não no fornecimento da dieta. O delineamento experimental foi inteiramente casualizado, em um esquema fatorial 2 x 2, totalizando quatro tratamentos, sendo: Dieta sem dipropionato de amônio fornecida duas vezes ao dia; Dieta sem dipropionato de amônio fornecida uma vez ao dia; Dieta com dipropionato de amônio fornecida duas vezes ao dia; Dieta com dipropionato de amônio fornecida uma vez ao dia. Utilizou-se 32 novilhos ½ sangue Angus ½ sangue Nelore, com idade média de 11 meses. O uso do dipropionato de amônio na média geral aumentou o ganho médio diário, a ingestão de matéria seca, e o ganho de carcaça. A dieta fornecida duas vezes ao dia proporcionou na média geral, maior ganho de peso, maior ganho de carcaça e melhor conversão alimentar. Ao avaliar a associação entre os tratamentos, o uso de dipropionato mais a dieta fornecida duas vezes ao dia mostrou maior ganho de carcaça diário, durante o período experimental e maior peso de carcaça quente (1,251 kg, 111,4 kg e 308,6 kg respectivamente), assim como garantiu melhor digestibilidade aparente da matéria seca (74,57%). Com os dados obtidos no presente estudo é possível afirmar que é recomendável utilizar o dipropionato de amônio mantendo o fracionamento da dieta para novilhos de corte em fase de terminação.

Palavras-chave:
características de carcaça; desempenho animal; digestibilidade da dieta; estabilizante químico; manejo alimentar

1. Introduction

Adequate feeding management is essential for a successful production system, and it must guarantee the supply of nutrients compatible with animal requirements. The fractional supply of the total mixed ration (TMR) to the animals is a common practice in many farms, however, the choice of which management to adopt must be thoroughly evaluated. Supplying TMR to cattle in a feedlot system only once a day can be a good strategy in terms of reducing labor costs (11 Mattachini G, Pompe J, Finzi A, Tullo E, Riva E, Provolo G. Effects of Feeding Frequency on the Lying Behavior of Dairy Cows in a Loose Housing with Automatic Feeding and Milking System. Animals, 2019;9(4):121. doi: http://doi.org/10.3390/ani9040121
http://doi.org/10.3390/ani9040121...
), however, when the diet contains silage in its composition, the longer exposure time to oxygen favors the activity of spoilage microorganisms, causing its deterioration that can reach the TMR, deteriorating the other ingredients (22 Borreani G, Tabacco E. Plastics in animal production. In a Guide to the Manufacture, Performance, and Potential of Plastics in Agriculture. Orzolek K. 1st ed. Elssevier, Amsterdan, The Netherlands. 2017. p. 145-185.).

When adopting this food management, the inclusion of propionic acid to the TMR at the time of its supply reduces losses due to its potential for microbiological control, and thus, ensures the maintenance of TMR quality, its greater use, improved productive performance, allowing to reduce the number of times the diet will be provided throughout the day (33 Windle M, Kung Jr L. The effect of a feed additive on the feeding value of a silage-based TMR exposed to air. Journal of Dairy Science. 2013;91:16., 44 Gheller LS, Ghizzi LG, Marques JA, Takiya CS, Grigoletto, NT, Dias, MS, Silva TBP, Nunes AT, Silva GG, Fernandes LGX, Rennno LN, Renno, FP. Effects of organic acid-based products added to total mixed ration on performance and ruminal fermentation of dairy cows. Animal Feed Science and Technology. 2020;261(sn):1803-1810. doi: http://doi.org/10.1016/j.anifeed-sci.2020.114406
http://doi.org/10.1016/j.anifeed-sci.202...
). Providing the diet twice a day, even if it is more expensive, makes the TMR stay fresh in the trough for longer, reducing the activity of spoilage microorganisms and can stimulate the intake of dry matter by the animals (55 Crossley RE, Harlander-Matauschek A, Devries TJ. Mitigation of variability between competitively fed dairy cows through increased feed delivery frequency. Journal of dairy Science. 2018;101(1):518-529. doi: http://doi.org/10.3168/jds.2017-12930
http://doi.org/10.3168/jds.2017-12930...
, 11 Mattachini G, Pompe J, Finzi A, Tullo E, Riva E, Provolo G. Effects of Feeding Frequency on the Lying Behavior of Dairy Cows in a Loose Housing with Automatic Feeding and Milking System. Animals, 2019;9(4):121. doi: http://doi.org/10.3390/ani9040121
http://doi.org/10.3390/ani9040121...
). Adding propionic acid to the TMR in management with supply twice a day can further enhance the productive performance and intake, due to its preservative role, as mentioned above, and also enhance favor (66 Quitmann H, Fan R, Czermak P. Acidic organic compounds in beverage, food, and feed production. Biotechnology of Food and Feed Additives. 2013;(143):91-141. doi: http://doi.org/10.1007/10_2013_262
http://doi.org/10.1007/10_2013_262...
).

Some studies using organic acids such as propionic acid have been developed, and these aimed to evaluate their effectiveness in preserving dietary nutrients throughout the day, that is, their potential to reduce losses and deterioration of nutrients from food (77 Santos JP, Souza VC, Barbosa EF, Silva RB, Avila CLS, Pereira RAN, Lobato DN, Pereira MN. Aerobic stability of total mixed ration with added microbial growth inhibitors. Journal of dairy Science. 2019;102(1):204., 44 Gheller LS, Ghizzi LG, Marques JA, Takiya CS, Grigoletto, NT, Dias, MS, Silva TBP, Nunes AT, Silva GG, Fernandes LGX, Rennno LN, Renno, FP. Effects of organic acid-based products added to total mixed ration on performance and ruminal fermentation of dairy cows. Animal Feed Science and Technology. 2020;261(sn):1803-1810. doi: http://doi.org/10.1016/j.anifeed-sci.2020.114406
http://doi.org/10.1016/j.anifeed-sci.202...
). Organic acids are used in the food industry to prevent deterioration and prolong the shelf life due to their antimicrobial activity and are characterized as food additives and preservatives (88 Cheng H. Volatile favor compounds in yogurt: a review. Critical reviews in food science and nutrition. 2010;50(10): 938-950., 99 Jurado-Sánchez B, Ballesteros E, Gallego M. Gas chromatographic determination of 29 organic acids in foodstufs after continuous solid-phase extraction. Talanta. 2011;84(3):924-930. doi: http://doi.org/10.1016/j.talanta.2011.02.031
http://doi.org/10.1016/j.talanta.2011.02...
, 1010 Mohan A, Pohlman F. Role of organic acids and peroxy-acetic acid as antimicrobial intervention for controlling Es-cherichia coli O157: H7 on beef trimmings. LWT-Food Science and Technology. 2016;65:868-873. doi: http://doi.org/10.1016/j.lwt.2015.08.077
http://doi.org/10.1016/j.lwt.2015.08.077...
), which ensures the maintenance of the quality of the TMR for longer periods (1111 Kung Junior L, Sheperd AC, Smagala AM, Endres KM, Bessett CA, Ranjit NK, Glancey JL. The effect of preservatives based on propionic acid on the fermentation and aerobic stability of corn silage and a total mixed ration. Journal of Dairy Science. 1998;81(5):1322-1330. doi: http://doi.org/10.3168/jds.S0022-0302(98)75695-4
http://doi.org/10.3168/jds.S0022-0302(98...
).

Seeking to elucidate gaps on these topics, especially in beef cattle, the present study evaluated the effect of ammonium dipropionate (antimicrobial stabilizer based on propionic acid) on TMR and also evaluated the fractional and non-fractional supply of the diet on the performance, carcass traits, and ingestive behavior of feedlot bulls in the finishing phase. The hypothesis was that the use of the stabilizer reduces the frequency of daily TMR supply, without impairing animal performance.

2. Material and methods

The experiment was carried out at the Laboratory of Food Analysis and Ruminant Nutrition, and at the Didactic, Research, and Extension Unit in Beef Cattle -Feedlot of the Animal Production Center (NUPRAN) along with the Master’s Program in Veterinary Sciences, Agricultural Sciences Sector and Environmental Studies, State University of the Midwest (CEDETEG/ UNICENTRO), located in the municipality of Guarapuava, state of Paraná, Brazil (25º23'02” S and 51º29'43” W). All experimental procedures were previously submitted to the Animal Research Ethics Committee (CEUA/UNICENTRO), having been approved for execution (Oficial Letter 056/2019).

Experimental animals were 32 bulls, ½ Angus and ½ Nellore, from the same herd, with an average age of 11 ± 2 months, an initial average body weight of 350 ± 5 kg, previously dewormed. This was a 2 x 2 factorial completely randomized experimental design, aiming to evaluate the inclusion of ammonium dipropionate in the diet combined with fractional and non-fractional supply, constituting four treatments: Diet without ammonium dipropionate supplied twice a day; Diet without ammonium dipropionate once a day; Diet with ammonium dipropionate twice a day; Diet with ammonium dipropionate diet once a day.

The facilities consisted of 16 feedlot pens, with 15 m2 each (2.5 m x 6.0 m). Each pen had a concrete trough measuring 2.30 m long, 0.60 m wide, and 0.35 m high, and a metal trough equipped with a foat for automatic water replenishment. The experimental period lasted 105 days, with 16 days for adaptation to diets and facilities, plus 89 days for data collection, divided into 3 periods, with two evaluation periods of 28 days each and a third period of 33 days.

The ammonium dipropionate used was the commercial product Mold-Zap® 55, registered with the Ministry of Agriculture, Livestock and Food Supply (MAPA) by the company Alltech, under number PR-05224 00049, REV.03.11 TB/REV1013PF, and is classified as a preservative additive based on propionic acid at a dose of 550 g kg-1, ammonium hydroxide at a dose of 120 g kg-1 and water. Animals assigned to treatments that received the fractional diet were fed at 06h00 and 17h00, and the animals that did not receive the fractional diet were fed only at 17h00. All diets were provided “ad libitum”. At the time of feeding, ammonium dipropionate was applied and homogenized. The dose used was 1.25 mL kg-1 TMR, which is recommended by the manufacturer.

Voluntary intake was recorded daily, by weighing the amount ofered and the leftovers from the previous day, considering the adjustment of daily intake, to allow leftovers at 5% of the total supplied. Diets consisted of 40% corn silage and 60% concentrate. The concentrate was prepared in the commercial feed factory of Cooperativa Agrária (Guarapuava, Paraná, Brazil), based on soybean meal, wheat bran, corn grain, malt radicle, calcitic limestone, dicalcium phosphate, livestock urea, common salt, mineral vitamin premix, as pellets. Samples of corn silage and concentrate were dried in a forced air oven at 50°C for 72 hours, to determine the partially dry matter. The pre-dried samples were ground in a Wiley mill with a 1mm diameter sieve and subsequently sent for chemical analysis.

The pre-dried samples of corn silage and concentrate were analyzed for contents of dry matter (DM), mineral matter (MM), ether extract (EE), and crude protein (CP), according to techniques described in AOAC(1212 Association Of Official Analytical Chemists -A.O.A.C.Official methods of analysis. 16.ed. Washington, D.C. 1995.). The content of neutral detergent fiber (NDF) was obtained according to Van Soest et al.(1313 Van Soest P.J, Robertson J.B, Lewis B.A. Carbohydrate methodology, metabolism, and nutritional implications in dairy cattle. Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science. 1991;74(10):3583-3597. doi: http://doi.org/10.3168/jds.S0022-0302(91)78551-2
http://doi.org/10.3168/jds.S0022-0302(91...
), using thermostable α-amylase and acid detergent fiber (ADF), according to Goering and Van Soest(1414 Goering HK, Van Soest PJ. Forage fiber analyses: (apparatus, reagents, procedures, and some applications). Washington, D.C.: Agricultural Research Service, U.S. Dept. of Agriculture; 1970. Disponível em: https://handle.nal.usda.gov/10113/CAT87209099
https://handle.nal.usda.gov/10113/CAT872...
). Total digestible nutrient (TDN) contents were calculated according to equations proposed by Weiss et al.(1515 Weiss WP, Conrad HR, St. Pierre NR. A theoretically-based model for predicting total digestible nutrient values of forages and concentrates. Animal Feed Science and Technology. 1992 Nov;39(1-2):95–110. doi: http://doi.org/10.1016/0377-8401(92)90034-4
http://doi.org/10.1016/0377-8401(92)9003...
). To determine the total dry matter, samples were oven-dried at 105ºC (1616 Silva DJ, Queiroz AC. Análise de Alimentos, métodos químicos e biológicos. 3rd ed. - 4ª reimpressão. Viçosa: Universidade Federal de Viçosa, 2009.), and to determine the P and Ca contents, analyses were carried out according to Tedesco et al.(1717 Tedesco MJ, Gianello C, Bissani CA, Bohnen H, Volhweiss SJ. Análises de solo, plantas e outros materiais. 2 ed. Porto Alegre: Universidade Federal do Rio Grande do Sul; 1995. 173p.).

Table 1 Chemical composition of silages and experimental diets
Composition Corn silage Concentrate TMR
Dry matter, % 28.99 90.40 59.70
Mineral matter, % DM 2.85 8.43 5.64
Crude protein, % DM 7.54 21.35 14.45
Ether extract, % DM 2.99 2.92 2.96
Neutral detergent fiber, % DM 47.05 24.72 35.89
Acid detergent fiber, % DM 26.61 8.65 17.63
Lignin, % DM 3.68 1.40 2.54
Ca, % 0.15 1.49 0.82
P, % 0.23 0.51 0.37
Total digestible nutrients, % 69.21 80.90 75.06
  • Premix guaranteed level per kg concentrate:16,000 IU vit. A; 2,000 IU vit. D3; 25 IU vit. E, 0.36 g S; 0.74 g Mg; 3.6 g Na; 0.52 mg Co; 22.01 mg Cu; 1.07 mg I; 72.80 mg Mn; 0.64 mg Se; 95.20 mg Zn and 40 mg sodium monensin.
  • Bulls were individually weighed at the end of each experimental period, after solid fasting for 10 hours. For animal performance, body weight (BW), dry matter intake, expressed in kg animal day-1 (DMI), dry matter intake, expressed as a percentage of body weight (DMI, % BW), average daily weight gain (ADG, kg day-1) and feed conversion (FC, kg kg-1). DMI was measured through the difference between the daily amount of food supplied and the amount of leftovers from the previous day. DMI, % BW was obtained by the ratio of DMI to the mean BW for the period, multiplied by 100 (DMI, % BW= DMI/BW*100). ADG was considered as the difference between the final (BWf) and initial BW (BWi) of the experimental period divided by the evaluated days (ADG = BWf - BWi/28 and/or 33). FC was obtained by the ratio of DMI to ADG (FC= DMI/ADG).

    During the experiment, feces of each pen were daily scored, by visual inspection. This evaluation followed the methodology adapted from Looper et al.(1818 Looper ML, Stokes SR, Waldner DN, Jordan ER. Managing Milk Composition: Evaluating Herd Potential. Cooperative Extension Service College of Agriculture and Home Economics. 2001;104(sn). Disponível em: http://AgriLifebookstore.org
    http://AgriLifebookstore.org...
    ) and Ferreira et al.(1919 Ferreira, SF, Guimarães, TP, Moreira, KKG, Alves, VA, Lemos, BJM, Souza, FM. Caracterização fecal de bovinos. Revista Científica Eletrônica de Medicina Veterinária. 2013;11(20):1-22.). The ingestive behavior was analyzed during the second evaluation period (day 42 of the experimental period), in a continuous time of 48 hours, starting at noon on the first day and ending at noon on the third day of evaluation. Observations were taken by seven observers per shift, for 48 hours, in a rotation system every 6 hours, with readings taken at regular intervals of 3 minutes.

    Animal behavior data, represented by idleness, rumination, and liquid and solid intake, were expressed in hours day-1. On the same occasion, following the same methodology, the frequency of occurrence of feeding, watering, urination, and defecation activities, expressed in number of times per day, was observed. For nocturnal observations, the environment was maintained with artificial lighting, a condition kept since the beginning of the experimental period.

    The apparent digestibility of the diet was evaluated in two moments, also in a continuous time of 48 hours, one at the end of the first (initial phase) and another at the end of the third (final phase) experimental period; and from these two evaluations, the mean values were obtained. For this analysis, a homogeneous sample of the produced feces was taken and stored under refrigeration at intervals of six hours. After two consecutive days of collection, these were homogenized to form a composite sample for laboratory analysis. At the end of each shift, the total volume produced was estimated and the fecal pH was determined.

    Concomitantly, food was collected once a day during the apparent digestibility test, which was freezer-stored. After the end of the evaluation, samples were thawed, and homogenized to form a composite sample, per pen and treatment. The daily intake of food and leftovers was determined. Samples of diets and feces were dried in a forced air oven at 55°C to constant weight, and corrected for the total dry matter at 105°C, for determination of dry matter content. DM of leftovers and feces of each experimental unit was determined by the same procedures adopted in diet analysis.

    The DM digestibility coefficient (DC) of the experimental diets was calculated using the equation: DC (%) = [(g ingested nutrient – g excreted nutrient) / g ingested nutrient] x 100. At the end of the experimental period, animals were fasted for solids for 10 hours for weighing relative to the last evaluation period, and after that, animals were fed and weighed before transportation to the slaughterhouse, obtaining the farm weight.

    Carcass gain in the feedlot period (CG) expressed in kg was obtained by the difference between hot carcass weight at slaughter and the initial body weight (BW) of the animals under a theoretical carcass yield of 50%. Taking the feedlot period of 89 days as a basis, the average carcass gain (ACG) was also calculated, expressed in kg day-1, which is obtained by the ratio of CG to BW, as well as the efficiency of transformation of the dry matter ingested into carcass (ETC), expressed in kg DM kg carcass and the efficiency of transformation of weight gain into carcass, obtained by the ratio of ACG to ADG (ACG / ADG), expressed in %. For the calculations, hot carcass weights were used.

    Five development measures were taken in the carcasses: carcass length, leg length, arm length, arm perimeter, and round thickness according to the methodologies suggested by Muller (2020 Muller L. Normas para avaliação de carcaças e concurso de carcaça de novilhos. 2 ed. Santa Maria: Universidade Federal de Santa Maria, 1987. 31p.). At the time of slaughter, non-carcass components were weighed (head, tongue, tail, leather, paws, and testicle, which are called external components; and empty heart, kidneys, liver, lungs, spleen, full and empty rumen-reticulum, full and empty abomasum, full and empty omasum, full and empty intestines, which are called vital organs).

    Data collected for each variable were tested by analysis of variance with comparison of means at 5% significance, using the SAS statistical software(2121 SAS INSTITUTE. SAS/STAT user’s Guide: statistics, version 6. 4.ed. North Caroline, v.2, 1993. 943 p.). The analysis of each variable followed the statistical model: Yij = µ + DFi + ADj + (DFi*ADj)ijk + Eijkl; where: Yij = dependent variables; µ = Overall mean of all observations; DFi = diet fractionation effect of order “i”; ADj = Effect of ammonium dipropionate of order “j”; DFi*ADj = effect of the interaction between diet fractionation of order “i” and the use of ammonium dipropionate of order “j”; and Eijkl = Residual random effect.

    3. Results and discussion

    There was no interaction (P>0.05) between the inclusion of ammonium dipropionate and diet fractionation, on the performance of feedlot finished bulls (Table 2). For ADG kg day-1, DMI kg day-1, and DMI % BW, there was a significant difference (P<0.05) between the inclusion or not of ammonium dipropionate in the diet in both evaluation periods, whereas the FC showed a difference only in the first period (0 to 28 days). For both parameters, the use of ammonium dipropionate was better than not using it, that is, it increased daily intake and weight gain, and improved FC in the first period.As for fractionating or not the diet supply, there was a significant difference (P<0.05) for ADG kg day-1 and FC. Animals that received the diet twice a day showed greater weight gain and better FC compared to the animals that received the diet once a day in both evaluation periods.

    Table 2
    Performance of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    According to Kung et al.(1111 Kung Junior L, Sheperd AC, Smagala AM, Endres KM, Bessett CA, Ranjit NK, Glancey JL. The effect of preservatives based on propionic acid on the fermentation and aerobic stability of corn silage and a total mixed ration. Journal of Dairy Science. 1998;81(5):1322-1330. doi: http://doi.org/10.3168/jds.S0022-0302(98)75695-4
    http://doi.org/10.3168/jds.S0022-0302(98...
    ), the addition of propionic acid to TMR at the time of supply delayed food spoilage in the trough, reducing pH and temperature after 24 hours of exposure to O2. In addition, these authors state that one of the main objectives in using a stabilizer like ammonium dipropionate is to guarantee the potential of animal performance due to the provision of a stable and quality diet. Given this, although TMR stability was not evaluated in the present study, a better performance was observed, in the average daily gain of animals receiving food with better aerobic stability. This was achieved by the presence of ammonium dipropionate that preserved the TMR, or the fractional supply of the diet, which shortened the time the TMR remained in the trough, and animals had access to smaller portions with higher quality twice a day.

    Preserved foods exposed to O2 for longer tend to show the proliferation of microorganisms that cause heating and loss of nutritional value, generating a food of dubious quality, and reduced consumption by the animals(2222 Lindgren S, Pettersson K, Kaspersson A, Jonsson A, Lingvall P. Microbial dynamics during aerobic deterioration of silages. Journal of the Science of Food and Agriculture. 1985;36(9):765-774. doi: http://doi.org/10.1002/js-fa.2740360902
    http://doi.org/10.1002/js-fa.2740360902...
    ). Propionic acid guarantees greater stability to the TMR and enhances the favor (66 Quitmann H, Fan R, Czermak P. Acidic organic compounds in beverage, food, and feed production. Biotechnology of Food and Feed Additives. 2013;(143):91-141. doi: http://doi.org/10.1007/10_2013_262
    http://doi.org/10.1007/10_2013_262...
    ), thus these may have been the factors that influenced the increase in dry matter intake, both expressed in % body weight and in kg day-1, which ensured greater average daily weight gain, kg day-1 when ammonium dipropionate was used.

    The use of additives to inhibit undesirable fermentation favors the aerobic stability of preserved foods and results in food with reduced losses caused by exposure to O2, maintaining its nutritional value (2323 Bernardes TF, De Souza NSDS, Da Silva JSLP, Santos IAP, Faturi C, Domingues F. Uso de inoculante bacteriano e melaço na ensilagem de capim-elefante. Revista de Ciências Agrárias. 2013;56(2):173-178. doi: http://doi.org/10.4322/rca.2013.026.
    http://doi.org/10.4322/rca.2013.026....
    ). Propionic acid-based products can improve the aerobic stability of preserved foods after exposure to O2 (1111 Kung Junior L, Sheperd AC, Smagala AM, Endres KM, Bessett CA, Ranjit NK, Glancey JL. The effect of preservatives based on propionic acid on the fermentation and aerobic stability of corn silage and a total mixed ration. Journal of Dairy Science. 1998;81(5):1322-1330. doi: http://doi.org/10.3168/jds.S0022-0302(98)75695-4
    http://doi.org/10.3168/jds.S0022-0302(98...
    , 2424 Kung Jr L, Robinson J, Ranjit N, Chen J, Golt CM, Pesek JD. Microbial populations, fermentation end products, and aerobic stability of corn silage treated with ammonia or a propionic acid based preservative. Journal of dairy Science. 2000;83(7): 1479-1486. doi: http://doi.org/10.3168/jds.S0022-0302(00)75020-X
    http://doi.org/10.3168/jds.S0022-0302(00...
    ), thus the inclusion of ammonium dipropionate at the time of feeding the animals reduced losses in nutritional quality due to the good stability of the TMR, explaining the better FC compared to the group that did not receive ammonium dipropionate. The same may have occurred concerning diet fractionation, where the animals that were given two meals during the day, reached a better FC due to the time in which the diet remained exposed to O2.

    Table 3 lists data on carcass gain and efficiency of the transformation of the dry matter ingested into carcass. For CG, kg, and ACG, kg day-1, there was an interaction between the inclusion of ammonium dipropionate and diet fractionation. Animals that received two meals with the inclusion of ammonium dipropionate showed the highest mean values for CG, kg and ACG, kg day-1 (111.4 kg and 1.251 kg, respectively), but did not differ from animals fed once or twice a day without the inclusion of ammonium dipropionate in the diet, whereas the animals that were fed once a day with the inclusion of ammonium dipropionate had the lowest mean values for CG, kg and ACG, kg day-1 (91.7 kg and 1.030 kg, respectively). Regarding the parameters of ETC and ACG ADG-1, there was no interaction between the use of ammonium dipropionate and fractionation or not of the feeding. Only the ETC showed a statistical difference (P<0.05), where animals fed twice a day, on average, were more efficient.

    Table 3
    Gain and efficiency of carcass gain of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    The best ETC, as well as the highest mean value of GC and ACG of animals fed twice a day, is positive since the greater weight gain of these animals (Table 2) was converted into carcass and not into viscera, which in some cases may occur. The reduction in the frequency of supplying the diet to the animals may imply variations in ruminal functions (uniformity of rumen fermentation, reduced fiber digestion, and pH instability) throughout the day, and to obtain the best animal performance, such variations need to be avoided (2525 Snifen C.; Robinson P. Nutritional strategy. Canadian Journal of Animal Science. 1984;64(3): 529-542., 2626 French N, Kennelly J. Effects of feeding frequency on rumi-nal parameters, plasma insulin, milk yield, and milk composition in Holstein cows. Journal of Dairy Science. 1990;73(7):1857-1863., 2727 Kaufmann W. Influence of the composition of the ration and the feeding frequency on ph-regulation in the rumen and on feed in-take in ruminants. Livestock Production Science. 1976;3(2):103-114., 2828 Robinson P, Snifen C. Forestomach and whole tract digestibility for lactating dairy cows as influenced by feeding frequency. Journal of Dairy Science. 1985;68(4): 857-867.). Therefore, these variations probably did not occur in the animals fed twice a day, ensuring better performance. In addition, the inclusion of ammonium dipropionate in the TMR is advantageous, when combined with the fractional supply of the feed, since it resulted in an increase of 17.68% in carcass gain, compared to the group that received ammonium dipropionate along with the non-fractional supply.

    Table 4 lists results on farm body weight and the quantitative characterization of carcasses at slaughter. There was an interaction (P<0.05) between the inclusion or not of ammonium dipropionate and the fractional or non-fractional supply of the diet, for farm body weight, hot carcass weight, and carcass length, where the animals fed a diet with ammonium dipropionate twice a day were superior to the others (557.5 kg, 308.6 kg and 133.25 cm, respectively). The other parameters in Table 4 showed no interaction, however when analyzing the individual effect of the treatments, a significant difference (P<0.05) was detected for fat thickness, where the animals that received ammonium dipropionate in the diet were superior to those that did not receive it (5.50 mm versus 4.94 mm, respectively). The other evaluated parameters showed no statistical difference (P>0.05).

    Table 4
    Farm body weight and carcass traits of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    The greatest thickness of subcutaneous fat for animals receiving ammonium dipropionate in the diet may be related to greater preservation of soluble carbohydrates in the diet. A higher concentration of these carbohydrates and a possible association with ammonium dipropionate may favor the production of propionic acid in the rumen, and according to Kozloski (2929 Kozloski, GV. Bioquímica dos ruminantes. 2.ed. Santa Maria: Ed. Da UFSM, 2009. 216p) and Gonçalves et al. (3030 Gonçalves MF, Martins JMS, Oliveira MV, Carvalho CCM, Antunes MM, Ferreira IC, Olivalves, L. C. Ionóforos na alimentação de bovinos. Veterinária Notícias. 2012;18(2):131-146.), when propionic acid enters the gluconeogenesis cycle, it becomes a glucose precursor, stimulates insulin production, and when the animal is in a positive energy balance, this hormone is responsible for activating lipogenesis

    Values of fat thickness found in the present study are satisfactory, and important, because when there is little fat covering the carcass, qualitative losses may occur during carcass cooling, darkening its external face and shortening muscle fibers, which impair the visual pattern and the tenderness of the meat, leading to a commercial devaluation (2020 Muller L. Normas para avaliação de carcaças e concurso de carcaça de novilhos. 2 ed. Santa Maria: Universidade Federal de Santa Maria, 1987. 31p., 3131 Lawrie RA. Ciência da carne. Porto Alegre: Artmed; 2005. 384p.). In this context, it is worth emphasizing the importance of adding the antimicrobial in the TMR, as it improved performance (Table 3 and Table 4), and resulted in better carcass finishing. Even with no significant effect, the carcass yield deserves attention, because regardless of the fractional supply of the diet or the inclusion of the antimicrobial agent, carcass yield was greater than 54%, which is considered satisfactory. Carcass yields of this magnitude become attractive for meatpacking industries as they generate greater profitability (3232 Pinto AP, Abrahão JJDS, Marques JD, Nascimento WGD, Perotto D, Lugão SMB. Desempenho e características de carcaça de tourinhos mestiços terminados em confinamento com dietas à base de cana-de-açúcar em substituição à silagem de sorgo. Revista Brasileira de Zootecnia. 2010;39(1): 198-203. doi: http://doi.org/10.1590/S1516-35982010000100026
    http://doi.org/10.1590/S1516-35982010000...
    ).

    Non-carcass components represented by internal organs showed no interaction between the use of ammonium dipropionate and diet fractionation (Table 5). When evaluating the non-carcass components considering the inclusion or not of ammonium dipropionate, only the liver weight showed a difference (P<0.05), where the animals that received ammonium dipropionate in the diet had greater liver weights compared to those that did not receive it (1.07 kg against 0.93 kg, respectively). Therefore, when evaluating the non-carcass components considering the fractional or non-fractional supply of the diet, there was no significant difference (P>0.05).

    Table 5
    Mean proportion of non-carcass components of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    The liver plays an essential role in metabolic pathways. Food intake, energy requirements for maintenance, and weight gain directly influence the development of this organ (3333 Cumby Jennifer. Visceral organ development during restriction and re-alimentation. In: Cant, J. Proceedings of the course in ruminant digestion and metabolism –ANSC. Guelph: University of Guelph. 2000;23-29p.). Therefore, the heaviest livers were those of the animals that consumed the most DM (Table 2). The external components of the carcass, represented by the head, tongue, paws, tail, leather, and testicles (Table 6), showed no interaction (P>0.05) between the presence or absence of ammonium dipropionate in the feed and fractional or non-fractional supply of the diet, and likewise, when analyzing these components separately, there was no significant difference (P>0.05).

    Table 6
    Mean proportion of external components of the carcass of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    Studies of non-carcass components represented by the internal (Table 5) and external (Table 6) organs of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet are scarce in the literature. However, the lack of differences for these components is important from the producers’ point of view, since they are not remunerated for non-carcass components.

    The fecal score (Table 7) showed no differences (P>0.05) between treatments or periods evaluated. This lack of difference is a good result and demonstrates that regardless of the fractional supply of the diet or the inclusion of ammonium dipropionate, animals maintained an ideal score according to the classification by Kononof et al. (3434 Kononof P, Heinrichs J, Varga G. Using manure evaluation to enhance dairy cattle nutrition. Penn State College of Agricultural Sciences. Department of Dairy and Animal Science, 2002.), where the feces had a pasty consistency, producing piles from 2.54 to 5.08 cm in height, which according to these authors is normal and demonstrates adequate healthofthe animals.

    Table 7
    Fecal score of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    Table 8 lists the data on fecal output, fecal dry matter content, and fecal pH, in addition to the apparent digestibility of dry matter. Of these, there was interaction (P<0.05) between treatments only for fecal output and apparent dry matter digestibility. Fecal output in both natural and dry matter was higher for animals fed twice a day that received ammonium dipropionate in the diet (16.68 kg and 2.84 kg, respectively). The higher fecal output is justified due to higher DM intake (Table 2). The apparent digestibility of DM was higher in animals fed twice a day that received ammonium dipropionate in the diet, followed by animals fed once a day that received ammonium dipropionate in the diet (74.57% and 73.66%, respectively).

    Table 8
    Fecal output, dry matter content, apparent digestibility of dry matter, and fecal pH of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    The greater apparent digestibility for the diets with ammonium dipropionate may be a consequence of lower deterioration that occurs in the silage after exposure to O2. According to Horst et al. (3535 Horst EH, Junior V B, Neumann M, Souza AM, Junior ESS, Dochowat A. Carbohydrate fractionation, fermentation and aerobic stability of silages with different maize hybrids. Revista de Ciências Agrárias. 2019;42(4):1071-1077. doi: http://doi.org/10.19084/rca.17723
    http://doi.org/10.19084/rca.17723...
    ), when there is food degradation after its exposure to O2, molds emerge, DM reduces and digestibility decreases. When evaluating the effect of including or not a propionic acid-based additive in the TMR combined with the number of meals (1 or 2 times) to dairy cows, Dias et al. (3636 Dias MSS, Ghizzi LG, Marques JA, Nunes AT, Grigoletto NT, Gheller LS, Silva, TBP, Silva GG, Lobato DN, Silva LFC, Rennó, FP. Effects of organic acids in total mixed ration and feeding frequency on productive performance of dairy cows. Journal of Dairy Science, 2021;104(5):5405-5416. doi: http://doi.org/10.3168/jds.2020-19419
    http://doi.org/10.3168/jds.2020-19419...
    ) observed no significant differences (P<0.05) in fecal analysis, citing only a trend towards higher NDF digestibility.

    Table 9 lists the parameters of ingestive behavior represented by idleness, rumination, water, and food consumption expressed in hours day-1, under the effect of the presence or absence of ammonium dipropionate in the diet combined with the fractional or non-fractional supply of the diet, according to the feedlot phase, and there was no statistical difference (P>0.05) for the parameters.

    Table 9
    Ingestive behavior of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply of the diet.

    According to Bürger et al. (3737 Bürger PJ, Pereira JC, Queiroz ACD, Coelho Da Silva JF, Valadares Filho SC, Cecon PR, Casali ADP. Comportamento ingestivo em bezerros holandeses alimentados com dietas contendo diferentes níveis de concentrado. Revista Brasileira de Zootecnia. 2000;29(1):236-242. doi: http://doi.org/10.1590/S1516-35982000000100031
    http://doi.org/10.1590/S1516-35982000000...
    ) and Pinto et al. (3838 Pinto A, Marques J, Abrahão J, Nascimento W, Costa, MAT, Lugão SMB. Comportamento e eficiência ingestiva de tourinhos mestiços confinados com três dietas diferentes. Archivos de Zootecnia. 2010;59(227):427-434.), ingestive behavior is mainly influenced by the type and concentration of energy in the diet offered to the animals. Therefore, the lack of differences in behavioral parameters is important, as it shows that there were no variations between the diets tested in the present study. Table 10 presents the ingestive behavior parameters represented by the frequency of occurrence of feeding, drinking, urination, and defecation, expressed in times per day, under the effect of the presence or absence of ammonium dipropionate in the diet combined with the fractional or non-fractional supply of the diet, according to the feedlot period, and there was also no statistical difference (P>0.05) for the parameters.

    Table 10
    Ingestive behavior of feedlot finished bulls under the effect of the presence or absence of ammonium dipropionate in the feed combined with the fractional or non-fractional supply

    The results in Tables 9 and 10 indicated that adding or not adding ammonium dipropionate and/or fractioning or not the supply of the diet does not interfere with the ingestive behavior, but reinforces the idea that the main factor of change in the ingestive behavior of cattle is the composition of the diet these animals were given, that is, the forage: concentrate ratio, digestibility of dietary constituents, energy level and particle size (3939 Van Soest, P.J. Nutritional ecology of the ruminant. 2nd ed. Ithaca: Cornell University Press; 1994., 4040 De Barros RC, Júnior VRR, Saraiva EP, Mendes GA, Meneses, GCC, Oliveira CR, Rocha WJB, Aguiar ACR, Santos CCR. Comportamento ingestivo de bovinos nelore confinados com diferentes níveis de substituição de silagem de sorgo por cana-de-açúcar ou bagaço de cana amonizado com uréia. Revista Brasileira de Ciência Veterinária. 2011;18(1):6-13. doi: http://doi.org/10.4322/rbcv.2014.112
    http://doi.org/10.4322/rbcv.2014.112...
    , 4141 Rode L, Weakley D, Satter L. Effect of forage amount and particle size in diets of lactating dairy cows on site of digestion and microbial protein synthesis. Canadian Journal of Animal Science. 1985;65(1):101-111.).

    4. Conclusions

    The inclusion of ammonium dipropionate caused an overall average increase in weight gain, dry matter intake, and carcass gains. The supply of the diet twice a day also promoted, in the overall average, an increase in the average weight gain and carcass gains, as well as improved the feed conversion of the animals. The combination of ammonium dipropionate with the supply of the diet twice a day improved the carcass parameters and resulted in better apparent digestibility of dry matter.

    Acknowledgments

    Coordination for the Improvement of Higher Education Personnel (CAPES)

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    Publication Dates

    • Publication in this collection
      29 May 2023
    • Date of issue
      2023

    History

    • Received
      16 Nov 2022
    • Accepted
      14 Mar 2023
    • Published
      26 Apr 2023
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