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Cited by 2 publications
References 17 publications
Technical note: A novel approach to estimate dry matter intake of lactating dairy cows through multiple on-cow accelerometers
The objective of this study was to evaluate the feasibility of using multiple 3-dimensional accelerometers to estimated individual dry matter intake (DMI) of lactating dairy cows. Twenty-four Holstein cows in late lactation were assigned into 2 groups, a calibration group (n = 12) and a validation group (n = 12). All cows were fitted with 3 sensors that recorded 3-dimensional acceleration (i.e., x, y, and z) at 10-s intervals, 1 on the lateral side of the left hind leg and 2 attached directly to a halter over the nose and jaw area on the left side. Then, 3 accelerations were generated from each accelerometer (e.g., Leg-X, Leg-Y, and Leg-Z). Six new variables were created based on the change in acceleration in the nose and jaw accelerometers between 2 consecutive time points (e.g., LagJaw-X). For both groups (i.e., calibration and validation), cows were continuously video recorded while data on acceleration and intake of total mixed ration were collected for 10 consecutive days. Cows were fed once daily using an individual gate system, and individual refusals were recorded next day before morning feeding. Cows were fed a common lactating cow diet (17.9% crude protein; 1.70 Mcal/kg of dry matter). In the calibration group, individual eating bouts were obtained based on video recordings and merged with the corresponding accelerometer data. Then, a stepwise regression analysis was conducted using the REG procedure of SAS (SAS Institute, Cary, NC) to determine the ranges in acceleration that accounted for the highest variation in DMI (highest R 2 ) in each acceleration variable. All 32,767 potential acceleration combinations were tested in the validation group using the acceleration ranges predetermined in the calibration group. The CORR procedure of SAS was used to test the Pearson correlation coefficient (r) between the type of DMI [i.e., based on accelerations (DMI accel ) or actual DMI (DMI actual )]. The MIXED procedure of SAS was used to perform a repeated-measures analysis with type (DMI accel vs. DMI actual ), day, and their interaction (T × D) in the model. From this analysis, 8 candidate acceleration models were selected based on high r and similarity (P > 0.15) in terms of T and T × D between DMI accel and DMI actual . A simulated effect on DMI actual was artificially created in the validation group by dividing this group (n = 12) into high and low intake cows (n = 6/group; DMI of 24.1 vs. 18.7 kg/d), and the candidate models were tested to determine whether they were sensitive enough to detect this effect. From these candidate models, AEN (Leg-X + Jaw-Z + LagJaw-Z) showed a weak correlation (r = 0.36) between DMI accel and DMI actual , but DMI accel and DMI actual were highly similar (21.2 vs. 21.4 kg/d of DMI). In addition, this was the only model that could detect the simulated effect on DMI actual (22.1 vs. 20.3 kg/d of DMI) in the validation group. The fact that the simulated effect on DMI actual was detected based only on accelerations is highly significant, and models such as AEN could be substantial...
Technical note: A novel approach to estimate dry matter intake of lactating dairy cows through multiple on-cow accelerometers
The objective of this study was to evaluate the feasibility of using multiple 3-dimensional accelerometers to estimated individual dry matter intake (DMI) of lactating dairy cows. Twenty-four Holstein cows in late lactation were assigned into 2 groups, a calibration group (n = 12) and a validation group (n = 12). All cows were fitted with 3 sensors that recorded 3-dimensional acceleration (i.e., x, y, and z) at 10-s intervals, 1 on the lateral side of the left hind leg and 2 attached directly to a halter over the nose and jaw area on the left side. Then, 3 accelerations were generated from each accelerometer (e.g., Leg-X, Leg-Y, and Leg-Z). Six new variables were created based on the change in acceleration in the nose and jaw accelerometers between 2 consecutive time points (e.g., LagJaw-X). For both groups (i.e., calibration and validation), cows were continuously video recorded while data on acceleration and intake of total mixed ration were collected for 10 consecutive days. Cows were fed once daily using an individual gate system, and individual refusals were recorded next day before morning feeding. Cows were fed a common lactating cow diet (17.9% crude protein; 1.70 Mcal/kg of dry matter). In the calibration group, individual eating bouts were obtained based on video recordings and merged with the corresponding accelerometer data. Then, a stepwise regression analysis was conducted using the REG procedure of SAS (SAS Institute, Cary, NC) to determine the ranges in acceleration that accounted for the highest variation in DMI (highest R 2 ) in each acceleration variable. All 32,767 potential acceleration combinations were tested in the validation group using the acceleration ranges predetermined in the calibration group. The CORR procedure of SAS was used to test the Pearson correlation coefficient (r) between the type of DMI [i.e., based on accelerations (DMI accel ) or actual DMI (DMI actual )]. The MIXED procedure of SAS was used to perform a repeated-measures analysis with type (DMI accel vs. DMI actual ), day, and their interaction (T × D) in the model. From this analysis, 8 candidate acceleration models were selected based on high r and similarity (P > 0.15) in terms of T and T × D between DMI accel and DMI actual . A simulated effect on DMI actual was artificially created in the validation group by dividing this group (n = 12) into high and low intake cows (n = 6/group; DMI of 24.1 vs. 18.7 kg/d), and the candidate models were tested to determine whether they were sensitive enough to detect this effect. From these candidate models, AEN (Leg-X + Jaw-Z + LagJaw-Z) showed a weak correlation (r = 0.36) between DMI accel and DMI actual , but DMI accel and DMI actual were highly similar (21.2 vs. 21.4 kg/d of DMI). In addition, this was the only model that could detect the simulated effect on DMI actual (22.1 vs. 20.3 kg/d of DMI) in the validation group. The fact that the simulated effect on DMI actual was detected based only on accelerations is highly significant, and models such as AEN could be substantial...
Caracterização dos sistemas de produção de leite bovino em um município no semiárido brasileiro
A realização de diagnósticos das atividades agropecuárias torna-se essencial, principalmente naqueles municípios que dependem do setor para enriquecer o PIB e gerar emprego e renda, uma vez que, essas informações coletadas, direcionam políticas públicas eficientes. Objetivou-se investigar como encontram-se organizados e distribuídos os sistemas de produção de leite bovino do município de Quixeramobim/CE. Realizou-se para isso, uma pesquisa por meio da aplicação de um questionário aos pecuaristas durante a campanha de vacinação contra febre aftosa, tendo sido quantificadas algumas variáveis, tais como: produção de leite (L/dia), total de vacas (cabeças), vacas em lactação (cabeças), área da propriedade (ha), localização geográfica no município e, alguns índices zootécnicos derivados da relação das matrizes com o volume de leite produzido. Observou-se que Quixeramobim produz aproximadamente 151.602 L/dia de leite, com um total de vacas ordenhadas de 15.694 (cabeças), tendo os distritos de Damião Carneiro e Encantado o maior (29.538 L/dia) e menor (5.629 L/dia) volumes produzidos, respectivamente. Notou-se ainda que os distritos de Nenelândia e Encantado, foram os que apresentaram os maiores (17%) e menores (3%) números de produtores em relação ao total, respectivamente do município, sendo que, grande parte destes, de acordo coma condição de uso da terra, são proprietários (43%), e pequena parte (4%) considerados como moradores. Quixeramobim tem a bovinocultura leiteira como uma das principais atividades, tendo sido essa caracterizada pela alta variabilidade em todo o seu território, o que é um indicativo no momento da geração e aplicação de políticas públicas específicas, levando-se em consideração as especificidades de cada local.
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