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<p>The objective of the study was to estimate nitrogen excretions in urine and faeces of lactating cows from three small dairy farms, representing intensive (IF), semi-intensive (SIF) and extensive management (EF) in the highlands of central México. Farms (treatments) were visited once a month (experimental period (EP)) during six months to record milk yield (MY; kg/cow/day), milk composition (fat, protein and lactose; g/kg), body weight (BW, kg) and body condition score (BCS), of six different cows each time per far, in order to represent average farm nitrogen excretions, rather than cows of specific characteristics. IF and SIF were based on temperate pastures under grazing management, supplementing cows twice a day at milking; whereas the EF was based on tropical pastures under extensive grazing management, supplementing cows at milking once a day. Urine nitrogen excretions (UNE) and faecal nitrogen excretions (FNE) (g/day/cow) were estimated using equations from the literature, based on nitrogen intake as a predictor. Farms were considered as treatments analysed as complete random design, using a Mixed model procedure in SAS. There were significant differences (<i>P</i> &lt; 0.05) of cow’s performance between farms. Dietary crude protein ranged from 136.0 (EF, to 148.0 (SIF) and 153.0 (IF), which are considered moderate to low. Nitrogen intakes of cows from IF and SIF were statistically the same (<i>P</i> &gt; 0.05) with a mean of 440.0&#xa0;g/day, being higher than 314.8&#xa0;g/day of intakes of cows from EF. These low DCP levels and nitrogen intakes, determined low UNE (131.6&#xa0;g/cow/day) and low FNE (139.5&#xa0;g/cow/day). Out of the total manure nitrogen excretions (TMNE), 49 and 51% of nitrogen (N) were excreted in urine and faeces, respectively. Mean nitrogen utilization efficiency (NUE) was 20.3%. The estimated excretions of nitrogen in urine and faeces from dairy cows in small farms in the highlands of central México were low. Cows of farms with high milk yields, had higher nitrogen intakes resulting in higher manure nitrogen excretions. However, much work is needed to increase nitrogen utilization efficiency of cows in small dairy farms.</p>

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Productive performance and estimations of urine and faecal nitrogen excretions of lactating cows in small dairy farms in the highlands of México

  • 期刊论文

  • 发表日期：

    2025年10月13日

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  • Benito Albarrán-Portillo,
  • Anastacio García-Martínez,
  • Nicolás López-Villalobos,
  • María Danae Celis Álvarez,
  • Carlos M. Arriaga-Jordán,
  • Sherezada Esparza-Jiménez

摘要

The objective of the study was to estimate nitrogen excretions in urine and faeces of lactating cows from three small dairy farms, representing intensive (IF), semi-intensive (SIF) and extensive management (EF) in the highlands of central México. Farms (treatments) were visited once a month (experimental period (EP)) during six months to record milk yield (MY; kg/cow/day), milk composition (fat, protein and lactose; g/kg), body weight (BW, kg) and body condition score (BCS), of six different cows each time per far, in order to represent average farm nitrogen excretions, rather than cows of specific characteristics. IF and SIF were based on temperate pastures under grazing management, supplementing cows twice a day at milking; whereas the EF was based on tropical pastures under extensive grazing management, supplementing cows at milking once a day. Urine nitrogen excretions (UNE) and faecal nitrogen excretions (FNE) (g/day/cow) were estimated using equations from the literature, based on nitrogen intake as a predictor. Farms were considered as treatments analysed as complete random design, using a Mixed model procedure in SAS. There were significant differences (P < 0.05) of cow’s performance between farms. Dietary crude protein ranged from 136.0 (EF, to 148.0 (SIF) and 153.0 (IF), which are considered moderate to low. Nitrogen intakes of cows from IF and SIF were statistically the same (P > 0.05) with a mean of 440.0 g/day, being higher than 314.8 g/day of intakes of cows from EF. These low DCP levels and nitrogen intakes, determined low UNE (131.6 g/cow/day) and low FNE (139.5 g/cow/day). Out of the total manure nitrogen excretions (TMNE), 49 and 51% of nitrogen (N) were excreted in urine and faeces, respectively. Mean nitrogen utilization efficiency (NUE) was 20.3%. The estimated excretions of nitrogen in urine and faeces from dairy cows in small farms in the highlands of central México were low. Cows of farms with high milk yields, had higher nitrogen intakes resulting in higher manure nitrogen excretions. However, much work is needed to increase nitrogen utilization efficiency of cows in small dairy farms.